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  • 1.
    Abdelhamid, Hani Nasser
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Assiut University, Egypt.
    Surfactant assisted synthesis of hierarchical porous metal-organic frameworks nanosheets2019Inngår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 30, nr 43, artikkel-id 435601Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two-dimensional metal-organic frameworks show increasing research attention due to their unique properties including tunable thickness, simple packing into a film and membrane, and high surface-to-volume atom ratios. A bottom-up synthesis strategy using cetyltrimethylammonium bromide for the synthesis of copper-benzenedicarboxylate (Cu(BDC)) nanosheets is reported. The method offers the synthesis of hierarchical porous Cu(BDC) lamellae with micrometer lateral dimensions, and nanometer thickness (100-150 nm). Electron microscope (scanning and transmission), and N-2 adsorption isotherms confirm the formation of lamellae Cu(BDC) with mesopore size of 5-80 nm. The material has thermal stability up to 400 degrees C with good chemical stability in several organic solvents. However, the material transforms to another phase (Cu(BDC)(H2O)(2)) when soaked in water and alcohols. The transformation reduces crystal size and offers the formation of hydrogen bond resulting in an increase in the sorption of CO2 by similar to 10% compared to the pristine material Cu(BDC).

  • 2.
    Abdelhamid, Hani Nasser
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Assiut University, Egypt.
    Mathew, Aji P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Cellulose-Based Materials for Water Remediation: Adsorption, Catalysis, and Antifouling2021Inngår i: Frontiers in Chemical Engineering, E-ISSN 2673-2718, Vol. 3, artikkel-id 790314Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Cellulose-based materials have been advanced technologies that used in water remediation. They exhibit several advantages being the most abundant biopolymer in nature, high biocompatibility, and contain several functional groups. Cellulose can be prepared in several derivatives including nanomaterials such as cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidized cellulose nanofibrils (TOCNF). The presence of functional groups such as carboxylic and hydroxyls groups can be modified or grafted with organic moieties offering extra functional groups customizing for specific applications. These functional groups ensure the capability of cellulose biopolymers to be modified with nanoparticles such as metal-organic frameworks (MOFs), graphene oxide (GO), silver (Ag) nanoparticles, and zinc oxide (ZnO) nanoparticles. Thus, they can be applied for water remediation via removing water pollutants including heavy metal ions, organic dyes, drugs, and microbial species. Cellulose-based materials can be also used for removing microorganisms being active as membranes or antibacterial agents. They can proceed into various forms such as membranes, sheets, papers, foams, aerogels, and filters. This review summarized the applications of cellulose-based materials for water remediation via methods such as adsorption, catalysis, and antifouling. The high performance of cellulose-based materials as well as their simple processing methods ensure the high potential for water remediation.

     

  • 3.
    Abdelhamid, Hani Nasser
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Assiut University, Egypt; The British University in Egypt (BUE), Egypt.
    Sultan, Sahar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Wallenberg Wood Science Center, Sweden.
    Mathew, Aji P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Wallenberg Wood Science Center, Sweden.
    Three-Dimensional Printing of Cellulose/Covalent Organic Frameworks (CelloCOFs) for CO2 Adsorption and Water Treatment2023Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 15, nr 51, s. 59795-59805Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development of porous organic polymers, specifically covalent organic frameworks (COFs), has facilitated the advancement of numerous applications. Nevertheless, the limited availability of COFs solely in powder form imposes constraints on their potential applications. Furthermore, it is worth noting that COFs tend to undergo aggregation, leading to a decrease in the number of active sites available within the material. This work presents a comprehensive methodology for the transformation of a COF into three-dimensional (3D) scaffolds using the technique of 3D printing. As part of the 3D printing process, a composite material called CelloCOF was created by combining cellulose nanofibrils (CNF), sodium alginate, and COF materials (i.e., COF-1 and COF-2). The intervention successfully mitigated the agglomeration of the COF nanoparticles, resulting in the creation of abundant active sites that can be effectively utilized for adsorption purposes. The method of 3D printing can be described as a simple and basic procedure that can be adapted to accommodate hierarchical porous materials with distinct micro- and macropore regimes. This technology demonstrates versatility in its use across a range of COF materials. The adsorption capacities of 3D CelloCOF materials were evaluated for three different adsorbates: carbon dioxide (CO2), heavy metal ions, and perfluorooctanesulfonic acid (PFOS). The results showed that the materials exhibited adsorption capabilities of 19.9, 7.4–34, and 118.5–410.8 mg/g for CO2, PFOS, and heavy metals, respectively. The adsorption properties of the material were found to be outstanding, exhibiting a high degree of recyclability and exceptional selectivity. Based on our research findings, it is conceivable that the utilization of custom-designed composites based on COFs could present new opportunities in the realm of water and air purification.

  • 4. Abdullah, Omed Gh.
    et al.
    Tahir, Dana A.
    Kadir, K.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Kurdistan Institution for Strategic Studies and Scientific Research, Iraq.
    Optical and structural investigation of synthesized PVA/PbS nanocomposites2015Inngår i: Journal of materials science. Materials in electronics, ISSN 0957-4522, E-ISSN 1573-482X, Vol. 26, nr 9, s. 6939-6944Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Polymer nanocomposite based on polyvinyl alcohol (PVA) and lead sulfide (PbS) in the average radius of (1.88-2.23) nm, have been synthesized using the chemical reduction rote and solution casting technique for different concentrations of PbS. The characterization of the polymer nanocomposite films were carried out using UV-visible spectroscopy, SEM, and XRD. The effect of various concentration of PbS NP on the optical properties of the composite has been studied to understand the optimum conditions for the synthesis process. The nanocomposite film shows high UV and visible light absorptions in the wavelength range of (200-500) nm, which correspond to the characteristics of the PbS NPs. The significant decreasing trend of the direct allowed band gap of the nanocomposite was observed upon increasing the Pb source concentration, from (6.27 eV) for pure PVA to (2.34 eV) for 0.04 M PbS concentration, which is much higher than the energy gap of bulk PbS value (0.41 eV). The calculated values of the static refractive index of Cauchy dispersion model were in the range of (1.09-1.20). X-ray diffraction analysis confirmed the cubic nanocrystalline PbS phase formation.

  • 5.
    Abebe, Mihret
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Hedin, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Bacsik, Zoltan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Spherical and Porous Particles of Calcium Carbonate Synthesized with Food Friendly Polymer Additives2015Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 15, nr 8, s. 3609-3616Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Porous calcium carbonate particles were synthesized by adding solutions of Ca2+ to solutions of CO32- containing polymeric additives. Under optimized conditions well-defined aggregates of the anhydrous polymorph vaterite formed. A typical sample of these micrometer-sized aggregates had: a pore volume of 0.1 cm(3)/g, a pore width of similar to 10 nm, and a specific surface area of similar to 25-30 m(2)/ g. Only one mixing Order (calcium to carbonate) allowed the formation of vaterite, which was ascribed to the buffering capacity and relatively high pH of the CO32- solution. Rapid addition of the calcium chloride solution and rapid stirring promoted the formation of vaterite, due to the high supersaturation levels achieved. With xanthan gum, porous and micrometer-sized vaterite aggregates could be synthesized over a wide range of synthetic conditions. For the Other food grade polymers, hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), and sodium carboxyl methylcellulose, several intensive and extensive synthetic parameters had to be optimized to obtain pure vaterite and porous aggregates. HPMC and MC allowed well-defined spherical micrometer-sited particles to form. We expect that these spherical and porous particles of vaterite could be relevant to model studies as well as a controlled delivery of particularly large molecules.

  • 6. Abram, Emese
    et al.
    Gajdatsy, Gabor
    Hermann, Peter
    Ujhelyi, Ferenc
    Borbely, Judit
    Shen, James Zhijian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    The colour of monolithic zirconia restorations determined by spectrophotometric examination2019Inngår i: Advances in Applied Ceramics: Structural, Functional and Bioceramics, ISSN 1743-6753, E-ISSN 1743-6761, Vol. 118, nr 1-2, s. 3-8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective: The aim of this in vitro study is to examine the optical effects of monolithic zirconia of different translucency and thickness, combined with substrates of different colours. Materials and methods: Zirconia specimens of two colours (A2P1, WHITE) were used for the study, three try-in pastes (Variolink Esthetic); substrates were prepared from nine types of materials (six VITA SIMULATE, three metals). Measurements were carried out at the Faculty of Atomic Physics of the Technical University of Budapest with the state-of-the-art PerkinElmer (R) Lambda 1050 spectrophotometer. Results: The colouring of zirconia has a major effect on dE values resulting in different colour perceptibility and acceptability. Try-in pastes, however, have no significant effects overall. Conclusion: Applying coloured zirconia is highly eligible for preparing aesthetic crowns as their substrate-covering effect makes it possible to reproduce the desired colour. Uncoloured zirconia nonetheless is unaffected by the substrate material, especially above a certain layer thickness.

  • 7. Abram, Emese
    et al.
    Gajtdatsy, Gabor
    Feher, Dora
    Salata, Jozsef
    Beleznai, Szabolcs
    Hermann, Peter
    Borbely, Judit
    Shen, Zhijian James
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Spectrophotometric examination of the optical effects of monolithic multilayered zirconia with different substrates2020Inngår i: Advances in Applied Ceramics: Structural, Functional and Bioceramics, ISSN 1743-6753, E-ISSN 1743-6761, Vol. 119, nr 5-6, s. 261-266Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The goal of this study is to examine specific optical effects of multilayered and coloured monolithic zirconia considering thickness and substrates of different colours using one of the most advanced spectrophotometers of the world. Multilayered zirconia specimens were used for the study with the thickness range of 0.5-2.5 mm and six types of substrate materials and three types of metal substrates. Measurements were carried out at Budapest Technical University with a PerkinElmer (R) Lambda1050UV/Vis/NIR spectrophotometer. The substrate colour and the thickness of zirconia affects the optical results, with special regard to colour perceptibility and acceptability. Monochromatic and multilayer zirconia show both similarities and discrepancies in behaviour, i.e. spectral reflectance and Delta E. Owing to the multi-coloured characteristics of multilayered zirconia the optical effect of the substrate less predictable than in the case of monochromatic zirconia thus requiring more detailed planning and implementation.

  • 8. Abu-Omar, Mahdi M.
    et al.
    Barta, Katalin
    Beckham, Gregg T.
    Luterbacher, Jeremy S.
    Ralph, John
    Rinaldi, Roberto
    Román-Leshkov, Yuriy
    Samec, Joseph S. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sels, Bert F.
    Wang, Feng
    Guidelines for performing lignin-first biorefining2021Inngår i: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 14, nr 1, s. 262-292Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The valorisation of the plant biopolymer lignin is now recognised as essential to enabling the economic viability of the lignocellulosic biorefining industry. In this context, the lignin-first biorefining approach, in which lignin valorisation is considered in the design phase, has demonstrated the fullest utilisation of lignocellulose. We define lignin-first methods as active stabilisation approaches that solubilise lignin from native lignocellulosic biomass while avoiding condensation reactions that lead to more recalcitrant lignin polymers. This active stabilisation can be accomplished by solvolysis and catalytic conversion of reactive intermediates to stable products or by protection-group chemistry of lignin oligomers or reactive monomers. Across the growing body of literature in this field, there are disparate approaches to report and analyse the results from lignin-first approaches, thus making quantitative comparisons between studies challenging. To that end, we present herein a set of guidelines for analysing critical data from lignin-first approaches, including feedstock analysis and process parameters, with the ambition of uniting the lignin-first research community around a common set of reportable metrics. These guidelines comprise standards and best practices or minimum requirements for feedstock analysis, stressing reporting of the fractionation efficiency, product yields, solvent mass balances, catalyst efficiency, and the requirements for additional reagents such as reducing, oxidising, or capping agents. Our goal is to establish best practices for the research community at large primarily to enable direct comparisons between studies from different laboratories. The use of these guidelines will be helpful for the newcomers to this field and pivotal for further progress in this exciting research area.

  • 9. Adak, Vivekananda
    et al.
    Roychowdhury, Krishanu
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Cornell University, USA.
    Das, Sourin
    Spin Berry phase in a helical edge state: S-z nonconservation and transport signatures2020Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 102, nr 3, artikkel-id 035423Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Topological protection of edge state in quantum spin Hall systems relies only on time-reversal symmetry. Hence, S-z conservation on the edge can be relaxed which can have an interferometric manifestation in terms of spin Berry phase. Primarily it could lead to the generation of spin Berry phase arising from a closed loop dynamics of electrons. Our work provides a minimal framework to generate and detect these effects by employing both spin-unpolarized and spin-polarized leads. We show that spin-polarized leads could lead to resonances or antiresonances in the two-terminal conductance of the interferometer. We further show that the positions of these antiresonances (as a function of energy of the incident electron) get shifted owing to the presence of spin Berry phase. Finally, we present simulations of a device setup using KWANT package which put our theoretical predictions on a firm footing.

  • 10. Adnan, Mohammed Mostafa
    et al.
    Nylund, Inger-Emma
    Jaworski, Aleksander
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Hvidsten, Sverre
    Glomm Ese, Marit-Helen
    Glaum, Julia
    Einarsrud, Mari-Ann
    The Structure, Morphology, and Complex Permittivity of Epoxy Nanodielectrics with In Situ Synthesized Surface-Functionalized SiO22021Inngår i: Polymers, E-ISSN 2073-4360, Vol. 13, nr 9, artikkel-id 1469Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Epoxy nanocomposites have demonstrated promising properties for high-voltage insulation applications. An in situ approach to the synthesis of epoxy-SiO2 nanocomposites was employed, where surface-functionalized SiO2 (up to 5 wt.%) is synthesized directly in the epoxy. The dispersion of SiO2 was found to be affected by both the pH and the coupling agent used in the synthesis. Hierarchical clusters of SiO2 (10–60 nm) formed with free-space lengths of 53–105 nm (increasing with pH or SiO2 content), exhibiting both mass and surface-fractal structures. Reducing the amount of coupling agent resulted in an increase in the cluster size (~110 nm) and the free-space length (205 nm). At room temperature, nanocomposites prepared at pH 7 exhibited up to a 4% increase in the real relative permittivity with increasing SiO2 content, whereas those prepared at pH 11 showed up to a 5% decrease with increasing SiO2 content. Above the glass transition, all the materials exhibited low-frequency dispersion effect resulting in electrode polarization, which was amplified in the nanocomposites. Improvements in the dielectric properties were found to be not only dependent on the state of dispersion, but also the structure and morphology of the inorganic nanoparticles. 

  • 11. Adolphsen, Jens Q.
    et al.
    Gil, Vanesa
    Sudireddy, Bhaskar R.
    Bergström, Lennart
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Characterisation and processing of aqueous LaNi0.6Fe0.4O3 Suspensions into Porous Electrode Layers for Alkaline Water Electrolysis2019Inngår i: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 39, nr 4, s. 1271-1278Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The colloidal properties and processing of aqueous LaNi0.6.Fe0.4O3 suspensions into electrode layers with hierarchical pore sizes has been investigated by light scattering, electron microscopy and rheology. We found that the colloidal stability of the oxide particles and the resulting microstructure of the electrode layers were similar when dispersing the particles at their intrinsic pH, or when adding polyvinylpyrrolidone. The addition of the ammonium salt of poly(methaacrylic acid) resulted in a poor colloidal stability and the concentrated suspensions became viscoelastic during processing. Addition of rice starch resulted in an increase of the porosity but the cast electrode layers cracked and delaminated.

  • 12. Afzal, Muhammad
    et al.
    Saleemi, Mohsin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). KTH Royal Institute of Technology, Sweden.
    Wang, Baoyuan
    Xia, Chen
    Zhang, Wei
    He, Yunjuan
    Jayasuriya, Jeevan
    Zhu, Bin
    Fabrication of novel electrolyte-layer free fuel cell with semi-ionic conductor (Ba0.5Sr0.5Co0.8Fe0.2O3-delta- Sm0.2Ce0.8O1.9) and Schottky barrier2016Inngår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 328, s. 136-142Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Perovskite Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) is synthesized via a chemical co-precipitation technique for a low temperature solid oxide fuel cell (LTSOFC) (300-600 degrees C) and electrolyte-layer free fuel cell (EFFC) in a comprehensive study. The EFFC with a homogeneous mixture of samarium doped ceria (SDC): BSCF (60%:40% by weight) which is rather similar to the cathode (SDC: BSCF in 50%:50% by weight) used for a three layer SOFC demonstrates peak power densities up to 655 mW/cm(2), while a three layer (anode/ electrolyte/cathode) SOFC has reached only 425 mW/cm(2) at 550 degrees C. Chemical phase, crystal structure and morphology of the as-prepared sample are characterized by X-ray diffraction and field emission scanning electron microscopy coupled with energy dispersive spectroscopy. The electrochemical performances of 3-layer SOFC and EFFC are studied by electrochemical impedance spectroscopy (EIS). As-prepared BSCF has exhibited a maximum conductivity above 300 S/cm at 550 degrees C. High performance of the EFFC device corresponds to a balanced combination between ionic and electronic (holes) conduction characteristic. The Schottky barrier prevents the EFFC from the electronic short circuiting problem which also enhances power output. The results provide a new way to produce highly effective cathode materials for LTSOFC and semiconductor designs for EFFC functions using a semiconducting-ionic material.

  • 13.
    Agthe, Michael
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Wetterskog, Erik
    Bergström, Lennart
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Following the Assembly of Iron Oxide Nanocubes by Video Microscopy and Quartz Crystal Microbalance with Dissipation Monitoring2017Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 33, nr 1, s. 303-310Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have studied the growth of ordered arrays by evaporation-induced self-assembly of iron oxide nanocubes with edge lengths of 6.8 and 10.1 nm using video microscopy (VM) and quartz crystal microbalance with dissipation monitoring (QCM-D). Ex situ electron diffraction of the ordered arrays demonstrates that the crystal axes of the nanocubes are coaligned and confirms that the ordered arrays are mesocrystals. Time-resolved video microscopy shows that growth of the highly ordered arrays at slow solvent evaporation is controlled by particle diffusion and can be described by a simple growth model. The growth of each mesocrystal depends only on the number of nanoparticles within the accessible region irrespective of the relative time of formation. The mass of the dried mesocrystals estimated from the analysis of the bandwidth-shift-to-frequency-shift ratio correlates well with the total mass of the oleate-coated nanoparticles in the deposited dispersion drop.

  • 14.
    Aguilar Sánchez, Andrea
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Jalvo, Blanca
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Mathew, Aji P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Nano-cellulose coatings for antifouling polyethersulfone (PES) membranes2019Konferansepaper (Fagfellevurdert)
  • 15.
    Aguilar-Sanchez, Andrea
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Li, Jing
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Mautner, Andreas
    Jalvo, Blanca
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap.
    Pesquet, Edouard
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Mathew, Aji P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Revealing the interaction between nanopolysaccharides and E.Coli by biological studies and atomic force microscopyManuskript (preprint) (Annet vitenskapelig)
  • 16.
    Aguilar-Sánchez, Andrea
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Jalvo, Blanca
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Mathew, Aji P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Nano-cellulose coatings for antifouling and mechanically enhanced polyethersulfone (PES) membranes2019Inngår i: Nordic Polymer Days 2019: Book of Abstracts / [ed] Rita de Sousa Dias, Sulalit Bandyopadhyay, 2019, s. 92-92Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Membrane technology is commonly used for filtration processes of industrial wastewater. Using membranes for water filtration is a safe and energy efficient solution. One of the main problems that arises during the usage of membranes is the fouling effects. Fouling increases the membrane separation resistance, reduces productivity due to a flux decline and affect membrane selectivity. These effects can be avoid by modifying the surface of the membranes using bio-based materials such as nano-cellulose. Nano-cellulose is a great example of a material obtained from renewable resources, which provides high reinforcement and antifouling properties to membranes.

    The aim of this work was the development of coatings with cellulose nano-crystals (CNC) and Tempooxidized cellulose nano-fribrils (T-CNF) using polyvinyl-alcohol (PVOH), as binding phase to enhance mechanical and antifouling properties over pure commercial PES membranes. The coatings were chemically crosslinked to increase mechanical properties and to improve stability of the coating and avoid swelling. It is expected that by avoiding swelling, permeability remains stable through time. All coating formulations remained stable after 10 hours of crossflow filtration. Mechanical properties of the coated membranes were improved in both dry and wet conditions, showing higher values of tensile strenght and E modulus compared to the uncoated ones. In addition, coated membranes showed high hydrophilicity and low adherence of bovine serum albumin (BSA).

    The coatings developed showed stability over PES membranes and provide them with a nanostructured surface which showed an extended durability in use. The modified surface membranes presented good mechanical properties in dry and wet conditions, high flux, high hydrophilicity, resistance to BSA fouling and to different pH environments. Moreover, these modified membranes showed promising results for fast upscaling at industrial level due to the simplicity of the coating process and the availability of the materials in the market.

  • 17. Ahmed, Shafique
    et al.
    Zhang, Man
    Koval, Vladimir
    Zou, Lifong
    Shen, Zhijian James
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Chen, Riqing
    Yang, Bin
    Yan, Haixue
    Terahertz probing of low-temperature degradation in zirconia bioceramics2022Inngår i: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 105, nr 2, s. 1106-1115Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    ZrO2-based ceramics are widely used in biomedical applications due to its color, biocompatibility, and excellent mechanical properties. However, low-temperature degradation (LTD) introduces a potential risk for long-term reliability of these materials. The development of innovative nondestructive techniques, which can explore LTD in zirconia-derived compounds, is strongly required. Yttria stabilized zirconia, 3Y-TZP, is one of the well-developed ZrO2-based ceramics with improved resistance to LTD for dental crown and implant applications. Here, 3Y-TZP ceramic powders were pressed and sintered to study the LTD phenomenon by phase transition behavior. The LTD-driven tetragonal-to-monoclinic phase transition was confirmed by XRD. XPS analysis demonstrated that induced LTD reduced the oxygen vacancies which supports these findings. It is proved that after the degradation, the 3Y-TZP ceramics show the decreased dielectric permittivity at terahertz frequencies due to the crystallographic phase transformation. Terahertz nondestructive probe is a promising method to investigate LTD in zirconia ceramics.

  • 18. Ait Benhamou, Anass
    et al.
    Boukind, Soumia
    Khalili, Houssine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för materialkemi.
    Moubarik, Amine
    El Achaby, Mounir
    Kassab, Zineb
    Sehaqui, Houssine
    Strong and Flame-Resistant Nanocellulose Sheets Derived from Agrowastes via a Papermaking-Assisted Process2024Inngår i: acs applied polymer materials, ISSN 2637-6105, Vol. 6, nr 5, s. 2763-2776Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In recent decades, the production of nanocellulose has gained significant attention. Nanocellulose-based film materials have found widespread applications in various high-end sectors owing to their remarkable characteristics. Nevertheless, the limitation of certain functional properties, such as resistance to water and fire, has posed challenges to their broader utilization. In this study, we conducted a comparative investigation on the impact of two distinct chemical modifications, namely, TEMPO-mediated oxidation and phosphorylation, on the production of nanocellulose sheets via a papermaking-assisted process. This approach explores the synergistic effects of these modifications in enhancing the properties of cellulose nanofibers for nanopaper production. To achieve this, we proposed utilizing Henna stems as an alternative source of cellulosic material, aiming to harness untapped agricultural residues as a sustainable alternative to conventional sources such as wood and cotton. The phosphorylated Henna nanopaper exhibited substantial enhancements in terms of mechanical properties, wettability, fire resistance, and water vapor permeability when compared to the TEMPO-modified Henna nanopaper. In conclusion, our findings underscore the potential of Henna stems as an environmentally sustainable source of cellulose for nanofiber production, positioning it as a promising alternative to wood and other lignocellulosic sources for advanced applications.

  • 19.
    Akhtar, Farid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Luleå University of Technology, Sweden.
    Ogunwumi, Steven
    Bergström, Lennart
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Thin zeolite laminates for rapid and energy-efficient carbon capture2017Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 7, artikkel-id 10988Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thin, binder-less zeolite NaX laminates, with thicknesses ranging between 310 to 750 mu m and widths exceeding 50 mm and biaxial tensile strength in excess of 3 MPa, were produced by pulsed current processing. The NaX laminates displayed a high CO2 adsorption capacity and high binary CO2-over-N-2 and CO2-over-CH4 selectivity, suitable for CO2 capture from flue gas and upgrading of raw biogas. The thin laminates displayed a rapid CO2 uptake; NaX laminates with a thickness of 310 mu m were saturated to 40% of their CO2 capacity within 24 seconds. The structured laminates of 310 mu m thickness and 50 mm thickness would offer low pressure drop and efficient carbon capture performance in a laminate-based swing adsorption technology.

  • 20. Alammar, Tarek
    et al.
    Smetana, Volodymyr
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Pei, Hanwen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Hamm, Ines
    Wark, Michael
    Mudring, Anja-Verena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Ruhr-Universität Bochum, Germany.
    The Power of Ionic Liquids: Crystal Facet Engineering of SrTiO3 Nanoparticles for Tailored Photocatalytic Applications2021Inngår i: Advanced Sustainable Systems, ISSN 2366-7486, Vol. 5, nr 2, artikkel-id 2000180Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sonochemical synthesis of nano-sized SrTiO3 carried out at close to room temperature, in ionic liquids (ILs) allows the tuning of particle size and particle morphology, that is, tracht and habitus, as well as particle aggregation via the choice of the ionic liquids (ILs) as the reaction medium. The nanoparticles demonstrate high performance for photocatalytic water splitting and photodecomposition of organic material. To this end bis(trifluoromethanesulfonyl)amide ([Tf2N](-))-based ILs with cations of different properties with respect to specific interactions with the target material are investigated. Isolated, 15 +/- 1 nm sized nano-spheres of SrTiO3 are observed to form in [C(3)mimOH][Tf2N] ([C(3)mimOH](+) = 1-(3-hydroxypropyl)-3-methylimidazolium). Aggregation of small sized nanoparticles are observed to around 250 +/- 100 nm large cube-like formations in [C(4)mim][Tf2N] ([C(4)mim](+) = 1-butyl-3-methylimidazolium), raspberry-like in [C4Py][Tf2N] ([C4Py](+) butylpyridinium), and ball-like in [P-66614][Tf2N] ([P-66614](+) tetradecyltrihexyl phosphonium). Importantly, the different materials show different performance as photocatalysts. SrTiO3 prepared in [C(4)mim][Tf2N] shows the highest photocatalytic activity for H-2 evolution (1115.4 mu mol h(-1)) when using 0.025 wt% Rh as the co-catalyst, whereas the material prepared in [C(3)mimOH][Tf2N] shows the highest activity for the photocatalytic degradation of methylene blue (88%) under UV irradiation. The different photocatalytic activities can be correlated with the different crystal surface facets expressed in the respective nanosized SrTiO3 material, {110} for material obtained from [C(4)mim][Tf2N], and {100} for material from [C(3)mimOH][Tf2N]. First-principles density functional theory (DFT) calculations are used to support the experimental findings.

  • 21.
    Ali, Hasan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Uppsala University, Sweden; Forschungszentrum Jülich, Germany.
    Rusz, Jan
    Bürgler, Daniel E.
    Adam, Roman
    Schneider, Claus M.
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Thersleff, Thomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Noise-dependent bias in quantitative STEM-EMCD experiments revealed by bootstrapping2024Inngår i: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 257, artikkel-id 113891Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electron magnetic circular dichroism (EMCD) is a powerful technique for estimating element-specific magnetic moments of materials on nanoscale with the potential to reach atomic resolution in transmission electron microscopes. However, the fundamentally weak EMCD signal strength complicates quantification of magnetic moments, as this requires very high precision, especially in the denominator of the sum rules. Here, we employ a statistical resampling technique known as bootstrapping to an experimental EMCD dataset to produce an empirical estimate of the noise-dependent error distribution resulting from application of EMCD sum rules to bcc iron in a 3-beam orientation. We observe clear experimental evidence that noisy EMCD signals preferentially bias the estimation of magnetic moments, further supporting this with error distributions produced by Monte-Carlo simulations. Finally, we propose guidelines for the recognition and minimization of this bias in the estimation of magnetic moments.

  • 22. Ali, Sharafat
    et al.
    Ellison, Adam
    Luo, Jian
    Edén, Mattias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Composition-structure-property relationships of transparent Ca-Al-Si-O-N oxynitride glasses: The roles of nitrogen and aluminum2023Inngår i: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 106, nr 3, s. 1748-1765Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We explore the formation and composition–structure–property correlations of transparent Ca–Al–Si–O–N glasses, which were prepared by a standard melt-quenching technique using AlN as the nitrogen source and incorporating up to 8 at.% of N. Their measured physical properties of density, molar volume, compactness, refractive index, and hardness—along with the Young, shear, and bulk elastic moduli—depended roughly linearly on the N content. These effects are attributed primarily to the improved glass-network cross-linking from N compared to O, rather than the formation of higher-coordination AlO5 and AlO6 groups, where 27Al magic-angle-spinning nuclear magnetic resonance experimentation revealed that aluminum is predominately present in tetrahedral coordination as AlO4 units. Yet, several physical properties, such as the refractive index along with the bulk, shear, and Young's elastic moduli, increase concomitantly with the Al content of the glass. We discuss the incompletely understood mechanical–property boosting role of Al as observed both herein and in previous reports on oxynitride glasses, moreover suggesting glass-composition domains that are likely to offer optimal mechanical properties. 

  • 23. Ali, Sharafat
    et al.
    Hakeem, Abbas Saeed
    Eriksson, Mirva
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Wójcik, Natalia Anna
    A novel approach for processing CaAlSiON glass-ceramics by spark plasma sintering: Mechanical and electrical properties2022Inngår i: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 42, nr 1, s. 96-104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lithium containing glassy materials can be used as solid electrolytes or electrode materials for lithium-ion batteries due to their high energy density. Conventional melt-quenched Ca11Al14Si16O49N10 glass powder containing 24 e/o N, doped with Li-ions (1, 3, and 6 wt. %) and sintered by spark plasma sintering technique (SPS) was studied. The benefits of using SPS to produce glass-ceramics are rapid heating rates compared to conventional consolidation techniques and tuning of properties, adjusting the temperature, holding time (closed to Tg temperature), heating rate (solidification), and pressure (densification) profile during the heat treatment using SPS. Pure glass and glass-ceramic were obtained under identical SPS conditions and compared with pristine oxynitride and soda-lime-silicate (float) glasses. XRD and SEM analysis confirmed that increasing the amount of Li increases the crystallinity in the glass matrix. Nano-indentation analysis showed a decreased hardness and reduced elastic modulus values with the addition of Li-ions. The direct current conductivity increases with the addition of Li due to the high mobility of Li-ions. However, the float glass sample doped with 6 wt.% of Li exhibits even higher values of D.C. conductivity, than the analogously doped Ca11Al14Si16O49N10 glass. The magnitude of activation energy (more than 1 eV) is typical for an ion hopping mechanism and the D.C. conduction mechanism is dominated by Li+ hopping.

  • 24.
    Ali, Sk Imran
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). University of Kalyani, India.
    Lidin, Sven
    Johnsson, Mats
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Crystal Structure of the Disordered Non-Centrosymmetric Compound Fe0.43Mo2.56SbO9.52019Inngår i: Crystals, ISSN 2073-4352, Vol. 9, nr 1, artikkel-id 40Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Single crystals of Fe0.43Mo2.56SbO9.5 were obtained by hydrothermal techniques at 230 degrees C. The crystal structure was determined from single crystal X-ray diffraction data. The compound crystallizes in the non-centrosymmetric space group Pc with unit cell parameters a = 4.0003(2) angstrom, b = 7.3355(3) angstrom, c = 12.6985(6) angstrom, = 90 degrees. The crystal structure comprises five crystallographically independent M atoms and one Sb3+ atom, M atoms are of two kinds of partially occupied sites Mo6+ and Fe3+. The building blocks consist of [SbO3O0.5O0.5E] octahedra (E = lone electron pair) and [(Mo/Fe)O-6] octahedra. The M = (Mo, Fe) and O atoms are arranged in a distorted hexagonal 2D-net, not the Sb atoms. The distortion of the net and consequently the symmetry reduction results mainly from the location of the Sb atoms. Disorder manifests itself as a splitting of the metal sites and as a consequent shortening of the Mo-Fe distances. Six (Mo/Fe)O-6 octahedra are connected to form a pseudohexagonal channel. The Sb3+ atom is displaced from the pseudo-six-fold axis.

  • 25. Amaya, Andrew J.
    et al.
    Pathak, Harshad
    Modak, Viraj P.
    Laksmono, Hartawan
    Loh, N. Duane
    Sellberg, Jonas A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. SLAC National Accelerator Laboratory, United States; KTH Royal Institute of Technology, Sweden.
    Sierra, Raymond G.
    McQueen, Trevor A.
    Hayes, Matt J.
    Williams, Garth J.
    Messerschmidt, Marc
    Boutet, Sebastien
    Bogan, Michael J.
    Nilsson, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. SLAC National Acceleratory Laboratory, United States.
    Stan, Claudiu A.
    Wyslouzil, Barbara E.
    How Cubic Can Ice Be?2017Inngår i: The Journal of Physical Chemistry Letters, E-ISSN 1948-7185, Vol. 8, nr 14, s. 3216-3222Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using an X-ray laser, we investigated the crystal structure of ice formed by homogeneous ice nucleation in deeply supercooled water nanodrops (r approximate to 10 nm) at similar to 225 K The nanodrops were formed by condensation of vapor in a supersonic nozzle, and the ice was probed within 100 mu s of freezing using femtosecond wide-angle X-ray scattering at the Linac Coherent Light Source free-electron X-ray laser. The X-ray diffraction spectra indicate that this ice has a metastable, predominantly cubic structure; the shape of the first ice diffraction peak suggests stacking-disordered ice with a cubicity value, chi, in the range of 0.78 +/- 0.05. The cubicity value determined here is higher than those determined in experiments with micron-sized drops but comparable to those found in molecular dynamics simulations. The high cubicity is most likely caused by the extremely low freezing temperatures and by the rapid freezing, which occurs on a similar to 1 mu s time scale in single nanodroplets.

  • 26. An, Di
    et al.
    Li, Hezhen
    Xie, Zhipeng
    Zhu, Tianbin
    Luo, Xudong
    Shen, Zhijian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Tsinghua University, China.
    Ma, Jing
    Additive manufacturing and characterization of complex Al2O3 parts based on a novel stereolithography method2017Inngår i: International Journal of Applied Ceramic Technology, ISSN 1546-542X, E-ISSN 1744-7402, Vol. 14, nr 5, s. 836-844Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, we prepared Al2O3 ceramic green parts with complex geometry and architecture using an additive manufacturing process based on stereolithography. The rheological and thermal behavior of Al2O3 slurry was firstly examined and used to establish the conditions for molding and debinding. As opposed to previous researches that only focused on manufacture techniques, the sintering behavior and densification process were systematically investigated. In addition, special attentions were paid to the evolution of microstructure between green bodies and sintered parts. The results showed that debound parts were equipped with uniform particle packing and narrow pore size distribution. The dimensions of the Al2O3 parts changed anisotropically with the different processing steps. The densification process was greatly accelerated by the decrease in pore size and annihilating of interconnected pores in which significant grain growth was observed above 1450 degrees C. The sintered part also had a homogeneous microstructure and no interface between adjacent layers. High densification (relative density of 99.1%) and much desirable Vickers hardness (17.9 GPa) of Al2O3 parts were achieved at the sintering temperature of 1650 degrees C.

  • 27.
    Andersson, David
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Simple Models for Complex Nonequilibrium Problems in Nanoscale Friction and Network Dynamics2020Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This doctoral thesis investigates three different topics: How friction evolves in atomically thin layered materials (2D materials); How social dynamics can be used to model grand scale common-pool resource games; Benchmarking of various image reconstruction algorithms in atomic force microscopy experiments. While these topics are diverse, they share being complex out-of-equilibrium systems. Furthermore, our approach to these topics will be the same: using simple models to obtain qualitative information about a system's dynamics. In the case of atomically thin layered materials, we will be expanding on the influential Prandtl-Tomlinson model and obtain an improved model constituting a substantial improvement in the theoretical description of friction in these systems. In the context of social dynamics, we will introduce a novel model representing a new approach to consensus rates on social networks in relation to society spanning coordination problems. For the image reconstruction project, our ambition is to investigate a new method for recreating free-energy surfaces based on AFM experiment, however, for this project only preliminary results are included.

    Fulltekst (pdf)
    Simple Models for Complex Nonequilibrium Problems in Nanoscale Friction and Network Dynamics
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  • 28.
    Andersson, Linnéa
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Larsson, Per Tomas
    Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, Royal Institute of Technology.
    Wågberg, Lars
    Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, Royal Institute of Technology.
    Bergström, Lennart
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Wallenberg Wood Science Center, Stockholm.
    Evaluating pore space in macroporous ceramics with water-based porosimetry2013Inngår i: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 96, nr 6, s. 1916-1922Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We show that water-based porosimetry (WBP), a facile, simple, and nondestructive porosimetry technique, accurately evaluates both the pore size distribution and throat size distribution of sacrificially templated macroporous alumina. The pore size distribution and throat size distribution derived from the WBP evaluation in uptake (imbibition) and release (drainage) mode, respectively, were corroborated by mercury porosimetry and X-ray micro-computed tomography (μ-CT). In contrast with mercury porosimetry, the WBP also provided information on the presence of “dead-end pores” in the macroporous alumina.

  • 29. Anil, Athira
    et al.
    White, Jai
    dos Santos, Egon Campos
    Terekhina, Irina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Johnsson, Mats
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Pettersson, Lars Gunnar Moody
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cornell, Ann
    Salazar-Alvarez, German
    Effect of pore mesostructure on the electrooxidation of glycerol on Pt mesoporous catalysts2023Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 11, nr 31, s. 16570-16577Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Glycerol is a renewable chemical that has become widely available and inexpensive due to the increased production of biodiesel. Noble metal materials have shown to be effective catalysts for the production of hydrogen and value-added products through the electrooxidation of glycerol. In this work we develop three platinum systems with distinct pore mesostructures, e.g., hierarchical pores (HP), cubic pores (CP) and linear pores (LP); all with high electrochemically active surface area (ECSA). The ECSA-normalized GEOR catalytic activity of the systems follows HPC > LPC > CPC > commercial Pt/C. Regarding the oxidation products, we observe glyceric acid as the main three-carbon product (3C), with oxalic acids as the main two-carbon oxidation product. DFT-based theoretical calculations support the glyceraldehyde route going through tartronic acid towards oxalic acid and also help understanding why the dihydroxyacetone (DHA) route is active despite the absence of DHA amongst the observed oxidation products.

  • 30.
    Apostolopoulou Kalkavoura, Varvara
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Fijoł, Natalia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Wallenberg Wood Science Center, Sweden.
    Lombardo, Salvatore
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Ruiz-Caldas, Maria-Ximena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Mathew, Aji P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Wallenberg Wood Science Center, Sweden.
    In Situ Functionalisation and Upcycling of Post-Consumer Textile Blends into 3D Printable Nanocomposite Filaments2024Inngår i: Advanced Sustainable Systems, ISSN 2366-7486Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The linear lifecycle of the textile industry contributes to the enormous waste generation of post-consumer garments. Recycling or repurposing of post-consumer garments typically requires separation of the individual components. This study describes a novel and facile chemo-thermo-mechanical method for producing extrudable pellets, involving one-pot, 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation of post-consumer polycotton textiles, followed by mild mechanical treatment, all without isolating the constituents of the polycotton blend. The oxidized blend with high cellulose and carboxylate content of 1221 ± 82 mmol COO− per kg of cotton, is pelletised into a masterbatch and further in situ extruded into nanocomposite filaments for 3D printing. The carboxyl groups introduced on the polycotton-based filters enable cotton fibrillation into nanoscaled fibers during mechanical treatment and extrusion resulting to a variety of functional and high surface-finish quality models, including filters and fashion accessories. The electrostatic interactions with positively charged species, such as methylene blue (MB), facilitate their adsorption from water while exhibiting promising adsorption capacities. The adsorption of MB follows the Freundlich model and depends on the printed porosity of the filter. A “trash to treasure” concept for textile waste is further corroborated through the use of the developed 3D printing filament into commodity products.

  • 31.
    Apostolopoulou-Kalkavoura, Varvara
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Thermal Conductivity of Hygroscopic Foams Based on Cellulose Nanomaterials2021Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Biobased super-insulating materials could mitigate climate change by minimizing the use of petroleum-based materials, creating artificial carbon sinks and minimizing the energy needed to maintain pleasant interior conditions. Cellulose nanomaterials (CNM) produced from abundantly available cellulose sources constitute versatile, highly anisotropic raw materials with tunable surface chemistry and high strength. This thesis includes the evaluation of the thermal conductivity of isotropic and anisotropic CNM-based foams and aerogels and analysis of the dominant heat transfer mechanisms. 

    We have developed a customized measurement cell for hygroscopic materials in which the humidity and temperature are carefully controlled while the thermal conductivity is measured. Anisotropic cellulose nanofibrils (CNF) foams with varying diameters showed a super-insulating behavior perpendicular (radial) to the nanofibril direction, that depended non-linearly on the relative humidity (RH) and foam density. Molecular simulations revealed that the very low thermal conductivity is related to phonon scattering due to the increase of the inter-fibrillar gap with increasing RH that resulted in a 6-fold decrease of the thermal boundary conductance. The moisture-induced swelling exceeds the thermal conductivity increase due to water uptake at low and intermediate RH and resulted in a minimum thermal conductivity of 14 mW m-1 K-1 at 35% RH and 295 K for the foams based on the thinnest CNF.

    The density-dependency of the thermal conductivity of cellulose nanocrystal (CNC) foams with densities of 25 to 129 kg m-3 was investigated and a volume-weighted modelling of the solid and gas thermal conductivity contributions suggested that phonon scattering was essential to explain the low radial thermal conductivity, whereas the replacement of air with water and the Knudsen effect related to the nanoporosity in the foam walls had a small effect. Intermediate-density CNC foams (34 kg m-3) exhibited a radial thermal conductivity of 24 mW m-1 K-1 at 295 K and 20% RH, which is below the value for air.

    The moisture uptake of foams based on CNMs with different degree of crystallinity and surface modifications decreased significantly with increasing crystallinity and temperature. Molecular simulations showed that the narrow pore size distribution of the amorphous cellulose film, and the relatively low water adsorption in the hydration cell around the oxygen of the carboxyl group play an important role for the moisture uptake of amorphous and crystalline CNM-based materials.

    Isotropic CNF- and polyoxamer based foams as well as CNF-AL-MIL-53 (an aluminum‑based metal-organic framework) foams were both moderately insulating (>40 mW m-1 K-1) and comparable with commercial expanded polystyrene. The thermal conductivity of CNF and polyoxamer foams displayed a very strong RH dependency that was modelled with a modified Künzel’s model. The presence of hydrophobic AL-MIL-53 decreased the moisture uptake of CNF-AL-MIL-53 aerogels by 42% compared to CNF-polyoxamer foams.

    Solid and gas conduction are the main heat transfer mechanisms in hygroscopic nanofibrillar foams and aerogels that depend on the interfacial phonon scattering, Knudsen effect and water uptake. It is essential that the thermal conductivity measurements of hygroscopic CNM-based foams and aerogels are determined at controlled RH and that parameters such as the temperature, density, nanoporosity, fibril dimensions and alignment are characterized and controlled for systematic development and upscaling of biobased foams for applications in building insulation and packaging.

    Fulltekst (pdf)
    Thermal Conductivity of Hygroscopic Foams Based on Cellulose Nanomaterials
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  • 32.
    Apostolopoulou-Kalkavoura, Varvara
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Gordeyeva, Korneliya
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Lavoine, Nathalie
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Bergström, Lennart
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Thermal conductivity of hygroscopic foams based on cellulose nanofibrils and a nonionic polyoxamer2018Inngår i: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 2, s. 1117-1126Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanocellulose-based lightweight foams are promising alternatives to fossil-based insulation materials for energy-efficient buildings. The properties of cellulose-based materials are strongly influenced by moisture and there is a need to assess and better understand how the thermal conductivity of nanocellulose-based foams depends on the relative humidity and temperature. Here, we report a customized setup for measuring the thermal conductivity of hydrophilic materials under controlled temperature and relative humidity conditions. The thermal conductivity of isotropic foams based on cellulose nanofibrils and a nonionic polyoxamer, and an expanded polystyrene foam was measured over a wide range of temperatures and relative humidity. We show that a previously developed model is unable to capture the strong relative humidity dependence of the thermal conductivity of the hygroscopic, low-density nanocellulose- and nonionic polyoxamer-based foam. Analysis of the moisture uptake and moisture transport was used to develop an empirical model that takes into consideration the moisture content and the wet density of the investigated foam. The new empirical model could predict the thermal conductivity of a foam with a similar composition but almost 3 times higher density. Accurate measurements of the thermal conductivity at controlled temperature and relative humidity and availability of simple models to better predict the thermal conductivity of hygroscopic, low-density foams are necessary for the development of nanocellulose-based insulation materials.

  • 33.
    Apostolopoulou-Kalkavoura, Varvara
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för materialkemi.
    Hu, Shiqian
    Lavoine, Nathalie
    Garg, Mohit
    Linares, Mathieu
    Munier, Pierre
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för materialkemi.
    Zozoulenko, Igor
    Shiomi, Junichiro
    Bergström, Lennart
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för materialkemi.
    Humidity-Dependent Thermal Boundary Conductance Controls Heat Transport of Super-Insulating Nanofibrillar Foams2021Inngår i: Matter, ISSN 2590-2393, E-ISSN 2590-2385, Vol. 4, nr 1, s. 276-289Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cellulose nanomaterial (CNM)-based foams and aerogels with thermal conductivities substantially below the value for air attract significant interest as super-insulating materials in energy-efficient green buildings. However, the moisture dependence of the thermal conductivity of hygroscopic CNM-based materials is poorly understood, and the importance of phonon scattering in nanofibrillar foams remains unexplored. Here, we show that the thermal conductivity perpendicular to the aligned nanofibrils in super-insulating ice-templated nanocellulose foams is lower for thinner fibrils and depends strongly on relative humidity (RH), with the lowest thermal conductivity (14 mW m−1 K−1) attained at 35% RH. Molecular simulations show that the thermal boundary conductance is reduced by the moisture-uptake-controlled increase of the fibril-fibril separation distance and increased by the replacement of air with water in the foam walls. Controlling the heat transport of hygroscopic super-insulating nanofibrillar foams by moisture uptake and release is of potential interest in packaging and building applications.

  • 34.
    Apostolopoulou-Kalkavoura, Varvara
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Munier, Pierre
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Bergström, Lennart
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Thermally Insulating Nanocellulose-Based Materials2021Inngår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 33, nr 28, artikkel-id 2001839Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Thermally insulating materials based on renewable nanomaterials such as nanocellulose could reduce the energy consumption and the environmental impact of the building sector. Recent reports of superinsulating cellulose nanomaterial (CNM)-based aerogels and foams with significantly better heat transport properties than the commercially dominating materials, such as expanded polystyrene, polyurethane foams, and glass wool, have resulted in a rapidly increasing research activity. Herein, the fundamental basis of thermal conductivity of porous materials is described, and the anisotropic heat transfer properties of CNMs and films with aligned CNMs and the processing and structure of novel CNM-based aerogels and foams with low thermal conductivities are presented and discussed. The extraordinarily low thermal conductivity of anisotropic porous architectures and multicomponent approaches are highlighted and related to the contributions of the Knudsen effect and phonon scattering.

  • 35. Apostolopoulou-Kalkavoura, Varvara
    et al.
    Munier, Pierre
    Dlugozima, Lukasz
    Heuthe, Veit-Lorenz
    Bergström, Lennart
    Effect of density, phonon scattering and nanoporosity on the thermal conductivity of anisotropic cellulose nanocrystal foamsManuskript (preprint) (Annet vitenskapelig)
  • 36. Argyropoulos, Dimitris D. S.
    et al.
    Crestini, Claudia
    Dahlstrand, Christian
    Furusjö, Erik
    Gioia, Claudio
    Jedvert, Kerstin
    Henriksson, Gunnar
    Hulteberg, Christian
    Lawoko, Martin
    Pierrou, Clara
    Samec, Joseph S. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Ren Fuel K2B AB, Sweden; RenFuel Materials AB, Sweden; Chulalongkorn University, Thailand.
    Subbotina, Elena
    Wallmo, Henrik
    Wimby, Martin
    Kraft Lignin: A Valuable, Sustainable Resource, Opportunities and Challenges2023Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 16, nr 23, artikkel-id e202300492Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Kraft lignin, a by-product from the production of pulp, is currently incinerated in the recovery boiler during the chemical recovery cycle, generating valuable bioenergy and recycling inorganic chemicals to the pulping process operation. Removing lignin from the black liquor or its gasification lowers the recovery boiler load enabling increased pulp production. During the past ten years, lignin separation technologies have emerged and the interest of the research community to valorize this underutilized resource has been invigorated. The aim of this Review is to give (1) a dedicated overview of the kraft process with a focus on the lignin, (2) an overview of applications that are being developed, and (3) a techno-economic and life cycle asseeements of value chains from black liquor to different products. Overall, it is anticipated that this effort will inspire further work for developing and using kraft lignin as a commodity raw material for new applications undeniably promoting pivotal global sustainability concerns.

  • 37. Babizhetskyy, Volodymyr
    et al.
    Köhler, Jürgen
    Myakush, Oksana
    Smetana, Volodymyr
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Levytskyi, Volodymyr
    Mudring, Anja-Verena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    New intermetallics R1+xZr1−xNi (R = Er–Tm, x ~ 0.5) with the TiNiSi type of structure2021Inngår i: Intermetallics (Barking), ISSN 0966-9795, E-ISSN 1879-0216, Vol. 137, artikkel-id 107279Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new series of isostructural rare earth compounds R1+xZr1−xNi (R = Er, Tm, Lu; x ~ 0.5) was synthesized from the elements by arc melting and subsequent annealing at 870 K for 1400 h. The crystal structures of the intermetallic compounds were investigated by means of single-crystal X-ray diffraction. They all crystallize in the TiNiSi structure type (space group Pnma, No. 62, oP12). In R1+xZr1−xNi, the R/Zr statistical mixture leading to nonequiatomic compositions occupies the position corresponding to the nickel site of the TiNiSi structure type. The calculated shortest interatomic distances are close to the sums of the single-bond covalent radii of respective elements. Electronic structure calculations performed with the tight-binding LMTO method revealed the non-zero density of states at the Fermi level and suggest metallic character. R1+xZr1−xNi (R = Er, Tm, Lu; x ~ 0.5) undergoes no long-range magnetic ordering down to 2 K.

  • 38.
    Bacsik, Zoltán
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Hedin, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Adsorption of Carbonyl Sulfide on Propylamine Tethered to Porous Silica2018Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 34, nr 26, s. 7708-7713Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Carbonyl sulfide (COS) reacts slowly with amines in the aqueous solutions used to absorb CO2 from natural gas and flue gas and can also deactivate certain aqueous amines. The effects of COS on amines tethered to porous silica, however, have not been investigated before. Hence, the adsorption of COS on aminopropyl groups tethered to porous silica was studied using in situ IR spectroscopy. COS chemisorbed mainly and reversibly as propylammonium propylthiocarbamate ion pairs [R-NH(C= O)S- +H3N-R] under dry conditions. In addition, a small amount of another chemisorbed species formed slowly and irreversibly. Nevertheless, the CO2 capacities of the adsorbents were fully retained after COS was desorbed.

  • 39. Balafendiev, Rustam
    et al.
    Simovski, Constantin
    Millar, Alexander J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC). Stockholms universitet, Nordiska institutet för teoretisk fysik (Nordita).
    Belov, Pavel
    Wire metamaterial filled metallic resonators2022Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 106, nr 7, artikkel-id 075106Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work we study electromagnetic properties of a resonator recently suggested for the search of axions—a hypothetical candidate to explain dark matter. A wire medium loaded resonator (called a plasma haloscope when used to search for dark matter) consists of a box filled with a dense array of parallel wires electrically connected to top and bottom walls. We show that the homogenization model of a wire medium works for this resonator without mesoscopic corrections, and that the resonator quality factor Q at the frequency of our interest drops versus the growth of the resonator volume V until it is dominated by resistive losses in the wires. We find that even at room temperature metals like copper can give quality factors in the thousands—an order of magnitude higher than originally assumed. Our theoretical results for both loaded and unloaded resonator quality factors were confirmed by building an experimental prototype. We discuss ways to further improve wire medium loaded resonators.

  • 40. Bastien, G.
    et al.
    Roslova, Maria
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Technische Universität Dresden, Germany.
    Haghighi, M. H.
    Mehlawat, K.
    Hunger, J.
    Isaeva, A.
    Doert, T.
    Vojta, M.
    Büchner, B.
    Wolter, A. U. B.
    Spin-glass state and reversed magnetic anisotropy induced by Cr doping in the Kitaev magnet alpha-RuCl32019Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, nr 21, artikkel-id 214410Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Magnetic properties of the substitution series Ru1-xCrxCl3 were investigated to determine the evolution from the anisotropic Kitaev magnet alpha-RuCl3 with J(eff) = 1/2 magnetic Ru(3+ )ions to the isotropic Heisenberg magnet CrCl3 with S = 3/2 magnetic Cr3+ ions. Magnetization measurements on single crystals revealed a reversal of the magnetic anisotropy under doping, which we argue to arise from the competition between anisotropic Kitaev and off-diagonal interactions on the Ru-Ru links and approximately isotropic Cr-Ru and isotropic Cr-Cr interactions. In addition, combined magnetization, ac susceptibility, and specific-heat measurements clearly show the destabilization of the long-range magnetic order of alpha-RuCl3 in favor of a spin-glass state of Ru1-xCrxCl3 for a low doping of x similar or equal to 0.1. The corresponding freezing temperature as a function of Cr content shows a broad maximum around x similar or equal to 0.45.

  • 41. Battiston, S.
    et al.
    Boldrini, S.
    Saleemi, Mohsin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). KTH Royal Institute of Technology, Sweden.
    Famengo, A.
    Fiameni, S.
    Toprak, M. S.
    Fabrizio, M.
    Influence of Al and Mg Addition on Thermoelectric Properties of Higher Manganese Silicides Obtained by Reactive Sintering2017Inngår i: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 17, nr 3, s. 1668-1673Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Higher manganese silicides (HMS), represented by MnSix (x = 1.71-1.75), are promising p-type candidates for thermoelectric (TE) energy harvesting systems at intermediate temperature range. The materials are very attractive as they may replace lead based compounds due to their nontoxicity, low cost of starting materials, and high thermal and chemical stability. Dense pellets were obtained through fast reactive sintering by spark plasma sintering (SPS). The addition -or nanoinclusion, of Al and Mg permitted the figure of merit enhancement of the material obtained with this technique, reaching the highest value of 0.40 at 600 degrees C. Morphology, composition and crystal structure of the samples were characterized by electron microscopies, energy dispersive X-ray spectroscopy, and X-ray diffraction analyses, respectively.

  • 42. Bazuev, Gennady V.
    et al.
    Tyutyunnik, Alexander P.
    Korolev, Alexander V.
    Suard, Emmanuelle
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Tarakina, Nadezda V.
    The effect of manganese oxidation state on antiferromagnetic order in SrMn1-xSbxO3 (0 < x < 0.5) perovskite solid solutions2019Inngår i: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 7, nr 7, s. 2085-2095Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mixed-valence manganese (Mn3+/Mn4+) solid solution, SrMn1-xSbxO3, was prepared for the first time. Two ranges of solid solutions were found: (1) SrMn1-xSbxO3 (0.025 x 0.09) with monoclinically distorted 6H-SrMnO3 polytype (sp. gr. C/2c) and (2) SrMn1-xSbxO3 (0.17 x 0.50) with a tetragonal unit cell (sp. gr. I4/mcm). Crystal structure refinement using X-ray and neutron powder diffraction data showed that the structure of the monoclinic solid solution consists of corner-sharing octahedra around sites occupied by manganese and antimony ions and face-sharing octahedra around sites occupied by manganese ions only, while the tetragonal solid solution has a random distribution of B-site cations. The presence of long-range antiferromagnetic order with a Neel temperature of about 148 K for SrMn0.80Sb0.20O3 and about 280 K for SrMn0.925Sb0.075O3 was found from the results of DC and AC susceptibility and neutron diffraction experiments at 5 K and 80 K.

  • 43. Beal, Rachel E.
    et al.
    Zhou Hagström, Nanna
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. SLAC National Accelerator Laboratory, USA.
    Barrier, Julien
    Gold-Parker, Aryeh
    Prasanna, Rohit
    Bush, Kevin A.
    Passarello, Donata
    Schelhas, Laura T.
    Brüning, Karsten
    Tassone, Christopher J.
    Steinrück, Hans-Georg
    McGehee, Michael D.
    Toney, Michael F.
    Nogueira, Ana Flávia
    Structural Origins of Light-Induced Phase Segregation in Organic-Inorganic Halide Perovskite Photovoltaic Materials2020Inngår i: Matter, ISSN 2590-2393, E-ISSN 2590-2385, Vol. 2, nr 1, s. 207-219Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Organic-inorganic metal-halide perovskite materials offer a promising route to reducing the dollars-per-watt cost of solar energy due to their good optoelectronic properties and facile, scalable processing. Compositional tuning allows for the preparation of absorbers with band gaps tailor-made for specific tandem and single-junction applications, but photoinduced phase segregation in mixed-halide materials leads to the formation of low-band-gap regions that reduce the voltage of devices. This work explores the structural origins of photoinduced phase segregation in FA(y)Cs(1-y)Pb(BrxI1-x)(3) perovskite alloys. We use synchrotron X- ray diffraction to map the solvus between the cubic and cubic-tetragonal mixed-phase region and time-dependent photoluminescence to assess stability under illumination. We show that the correlation between crystallographic phase and phase-segregation behavior is imperfect, so phase is not the sole determinant of optical stability. Instead, we consider several possible mechanisms that could underlie the dependence of optical stability on perovskite composition.

  • 44. Bejhed, Rebecca S.
    et al.
    Strömme, Maria
    Svedlindh, Peter
    Ahlford, Annika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik. Stockholms universitet, Science for Life Laboratory (SciLifeLab).
    Strömberg, Mattias
    Magnetic nanobeads present during enzymatic amplification and labeling for a simplified DNA detection protocol based on AC susceptometry2015Inngår i: AIP Advances, E-ISSN 2158-3226, Vol. 5, nr 12, artikkel-id 127139Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Magnetic biosensors are promising candidates for low-cost point-of-care biodiagnostic devices. For optimal efficiency it is crucial to minimize the time and complexity of the assay protocol including target recognition, amplification, labeling and read-out. In this work, possibilities for protocol simplifications for a DNA biodetection principle relying on hybridization of magnetic nanobeads to rolling circle amplification (RCA) products are investigated. The target DNA is recognized through a padlock ligation assay resulting in DNA circles serving as templates for the RCA process. It is found that beads can be present during amplification without noticeably interfering with the enzyme used for RCA (phi29 polymerase). As a result, the bead-coil hybridization can be performed immediately after amplification in a one-step manner at elevated temperature within a few minutes prior to read-out in an AC susceptometer setup, i.e. a combined protocol approach. Moreover, by recording the phase angle xi = arctan(chi ''/chi'), where chi and chi '' are the in-phase and out-of-phase components of the AC susceptibility, respectively, at one single frequency the total assay time for the optimized combined protocol would be no more than 1.5 hours, often a relevant time frame for diagnosis of cancer and infectious disease. Also, applying the phase angle method normalization of AC susceptibility data is not needed. These findings are useful for the development of point-of-care biodiagnostic devices relying on bead-coil binding and magnetic AC susceptometry.

  • 45. Bejhed, Rebecca S.
    et al.
    Tian, Bo
    Eriksson, Kristofer
    Brucas, Rimantas
    Oscarsson, Sven
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Strömberg, Mattias
    Svedlindh, Peter
    Gunnarsson, Klas
    Magnetophoretic Transport Line System for Rapid On-Chip Attomole Protein Detection2015Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, nr 37, s. 10296-10302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A lab-on-a-chip traveling wave magnetophoresis approach for sensitive and rapid protein detection is reported. In this method, a chip-based magnetic microarray comprising lines of micrometer-sized thin film magnetic elements was used to control the movement of magnetic beads (MBs). The MBs and the chip were functionalized, forming a sandwich-type assay. The MBs were transported across a detection area, and the presence of target molecules resulted in the immobilization of MBs within this area. Target quantification was accomplished by MB counting in the detection area using an optical microscope. In order to demonstrate the versatility of the microarray, biotinylated antiavidin was selected as the target protein. In this case, avidin-functionalized MBs and an avidin-functionalized detection area were used. With a total assay time of 1 to 1.5 h (depending on the labeling approach used), a limit of detection in the attomole range was achieved. Compared to on-chip surface plasmon resonance biodetection systems, our method has a larger dynamic range and is about a factor of 500 times more sensitive. Furthermore, our MB transportation system can operate in any chip-based biosensor platform, thereby significantly improving traditional biosensors.

  • 46. Berastegui, Pedro
    et al.
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Valvo, Mario
    Electrochemical reactions of AgFeO2 as negative electrode in Li- and Na-ion batteries2018Inngår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 401, s. 386-396Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    AgFeO2 nanoparticles synthesized via precipitation at room temperature are investigated in Li- and Na-ion cells through electrode coatings with an alginate binder. The electrochemical reactions of AgFeO2 with Li+ and Na+ ions, as well as its role as alternative negative electrode in these cell systems are carefully evaluated. Initial Li uptake causes irreversible amorphization of the AgFeO2 structure with concomitant formation of Ag-0 nano particles. Further Li incorporation results in conversion into Fe nanoparticles and Li2O, together with Li-alloying of these Ag-0 clusters. Similar mechanisms are also found upon Na uptake, although such processes are hindered by overpotentials, the capacity and reversibility of the reactions with Na+ ions being not comparable with those of their Li+ counterparts. The behaviour of AgFeO2 at low potentials vs. Li+ /Li displays a synergic pseudo-capacitive charge storage overlapping Li-Ag alloying/de-alloying. This feature is exploited in full cells having deeply lithiated AgFeO2 and LiFePO4 as negative and positive electrodes, respectively. These environmentally friendly iron-based full cells exhibit attractive cycle performances with approximate to 80% capacity retention after 1000 cycles without any electrolyte additive, average round trip efficiency of approximate to 89% and operational voltage of 3.0 V combined with built-in pseudo-capacitive characteristics that enable high cycling rates up to approximate to 25C.

  • 47.
    Biendicho, Jordi Jacas
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). STFC Rutherford Appleton Laboratory, England.
    Roberts, Matthew
    Noréus, Dag
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Lagerqvist, Ulrika
    Smith, Ronald I.
    Svensson, Gunnar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Norberg, Stefan T.
    Eriksson, Sten G.
    Hull, Stephen
    In situ investigation of commercial Ni(OH)(2) and LaNi5-based electrodes by neutron powder diffraction2015Inngår i: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 30, nr 3, s. 407-416Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrochemical reactions at both positive and negative electrodes in a nickel metal hydride (Ni-MH) battery during charge have been investigated by in situ neutron powder diffraction. Commercially available beta-Ni(OH)(2) and LaNi5-based powders were used in this experiment as positive and negative electrodes, respectively. Exchange of hydrogen by deuterium for the beta-Ni(OH)(2) electrode was achieved by ex situ cycling of the cell prior to in situ measurements. Neutron diffraction data collected in situ show that the largest amount of deuterium contained at the positive electrode is de-intercalated from the electrode with no phase transformation involved up to similar to 100 mA h/g and, in addition, the 110 peak width for the positive electrode increases on charge. The negative electrode of composition MmNi(3.6)Al(0.4)Mn(0.3)Co(0.7), where Mm = Mischmetal, exhibits a phase transformation to an intermediate hydride gamma phase first and then to the beta phase on charge. Unit cell dimensions and phase fractions have been investigated by Rietveld refinement of the crystal structure.

  • 48. Bischak, Connor G.
    et al.
    Lai, Minliang
    Fan, Zhaochuan
    Lu, Dylan
    David, Philippe
    Dong, Dengpan
    Chen, Hong
    Etman, Ahmed S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Alexandria University, Egypt.
    Lei, Teng
    Sun, Junliang
    Grünwald, Michael
    Limmer, David T.
    Yang, Peidong
    Ginsberg, Naomi S.
    Liquid-like Interfaces Mediate Structural Phase Transitions in Lead Halide Perovskites2020Inngår i: Matter, ISSN 2590-2393, E-ISSN 2590-2385, Vol. 3, nr 2, s. 534-545Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Microscopic pathways of structural phase transitions inmetal halide perovskites are difficult to probe because they occur over disparate time and length scales and because electron-based microscopies typically used to directly probe nanoscale dynamics of phase transitions often damage metal halide perovskite materials. Using in situ nanoscale cathodoluminescence microscopy with low electron beam exposure, we visualize nucleation and growth in the thermally driven transition to the perovskite phase in hundreds of non-perovskite phase nanowires. In combination with molecular dynamics simulations, we reveal that the transformation does not follow a simple martensitic mechanism, but proceeds despite a substantial energy barrier via ion diffusion through a liquid-like interface between the two structures. While cations are disordered in this liquid-like region, the halide ions retain substantial spatial correlations. This detailed picture not only reveals how phase transitions between disparate structures can proceed, but also opens the possibility to control such processes.

  • 49. Boily, Jean-Francois
    et al.
    Yesilbas, Merve
    Uddin, Munshi Md. Musleh
    Lu, Baiqing
    Trushkina, Yulia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Salazar-Alvarez, German
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Thin Water Films at Multifaceted Hematite Particle Surfaces2015Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, nr 48, s. 13127-13137Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Mineral surfaces exposed to moist air stabilize nanometer- to micrometer-thick water films. This study resolves the nature of thin water film formation at multifaceted hematite (alpha-Fe2O3) nanoparticle surfaces with crystallographic faces resolved by selected area electron diffraction. Dynamic vapor adsorption (DVA) in the 0-19 Torr range at 298 K showed that these particles stabilize water films consisting of up to 4-5 monolayers. Modeling of these data predicts water loadings in terms of an adsorption regime (up to 16 H2O/nm(2)) involving direct water binding to hematite surface sites, and of a condensation regime (up to 34 H2O/nm(2)) involving water binding to hematite-bound water nanodusters. Vibration spectroscopy identified the predominant hematite surface hydroxo groups (-OH, mu-OH, mu(3)-OH) through which first layer water molecules formed hydrogen bonds, as well as surface iron sites directly coordinating water molecules (i.e., as geminal eta-(OH2)(2) sites). Chemometric analyses of the vibration spectra also revealed a strong correspondence in the response of hematite surface hydroxo groups to DVA-derived water loadings. These findings point to a near-saturation of the hydrogen-bonding environment of surface hydroxo groups at a partial water vapor pressure of similar to 8 Torr (similar to 40% relative humidity). Classical molecular dynamics (MD) resolved the interfacial water structures and hydrogen bonding populations at five representative crystallographic faces expressed in these nanoparticles. Simulations of single oriented slabs underscored the individual roles of all (hydro)oxo groups in donating and accepting hydrogen bonds with first layer water in the adsorption regime. These analyses pointed to the preponderance of hydrogen bond-donating -OH groups in the stabilization of thin water films. Contributions of mu-OH and mu(3)-OH groups are secondary, yet remain essential in the stabilization of thin water films. MD simulations also helped resolve crystallographic controls on water water interactions occurring in the condensation regime. Water water hydrogen bond populations are greatest on the (001) face, and decrease in importance in the order (001) > (012) approximate to (110) > (014) >> (100). Simulations of a single (similar to 5 nm x similar to 6 nm x similar to 6 nm) nanometric hematite particle terminated by the (001), (110), (012), and (100) faces also highlighted the key roles that sites at particle edges play in interconnecting thin water films grown along contiguous crystallographic faces. Hydroxo water hydrogen bond populations showed that edges were the preferential loci of binding. These simulations also suggested that equilibration times for water binding at edges were slower than on crystallographic faces. In this regard, edges, and by extension roughened surfaces, are expected to play commanding roles in the stabilization of thin water films. Thus, in focusing on the properties of nanometric-thick water layers at hematite surfaces, this study revealed the nature of interactions between water and multifaced particle surfaces. Our results pave the way for furthering our understanding of mineral-thin water film interfacial structure and reactivity on a broader range of materials.

  • 50.
    Borysov, Stanislav S.
    et al.
    Stockholms universitet, Nordiska institutet för teoretisk fysik (Nordita).
    Olsthoorn, Bart
    Stockholms universitet, Nordiska institutet för teoretisk fysik (Nordita). Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Gedik, Mehmet Berk
    Stockholms universitet, Nordiska institutet för teoretisk fysik (Nordita). KTH Royal Institute of Technology, Sweden.
    Geilhufe, R. Matthias
    Stockholms universitet, Nordiska institutet för teoretisk fysik (Nordita).
    Balatsky, Alexander V.
    Stockholms universitet, Nordiska institutet för teoretisk fysik (Nordita). University of Connecticut, USA.
    Online search tool for graphical patterns in electronic band structures2018Inngår i: npj Computational Materials, E-ISSN 2057-3960, Vol. 4, artikkel-id 46Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many functional materials can be characterized by a specific pattern in their electronic band structure, for example, Dirac materials, characterized by a linear crossing of bands; topological insulators, characterized by a Mexican hat pattern or an effectively free electron gas, characterized by a parabolic dispersion. To find material realizations of these features, manual inspection of electronic band structures represents a relatively easy task for a small number of materials. However, the growing amount of data contained within modern electronic band structure databases makes this approach impracticable. To address this problem, we present an automatic graphical pattern search tool implemented for the electronic band structures contained within the Organic Materials Database. The tool is capable of finding user-specified graphical patterns in the collection of thousands of band structures from high-throughput calculations in the online regime. Using this tool, it only takes a few seconds to find an arbitrary graphical pattern within the ten electronic bands near the Fermi level for 26,739 organic crystals. The source code of the developed tool is freely available and can be adapted to any other electronic band structure database.

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