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Publications (10 of 150) Show all publications
Hadi, S. E., Yeprem, H. A., Åhl, A., Morsali, M., Kapuscinski, M., Kriechbaum, K., . . . Bergström, L. (2023). Highly magnetic hybrid foams based on aligned tannic acid-coated iron oxide nanoparticles and TEMPO-oxidized cellulose nanofibers. RSC Advances, 13(20), 13919-13927
Open this publication in new window or tab >>Highly magnetic hybrid foams based on aligned tannic acid-coated iron oxide nanoparticles and TEMPO-oxidized cellulose nanofibers
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2023 (English)In: RSC Advances, E-ISSN 2046-2069, Vol. 13, no 20, p. 13919-13927Article in journal (Refereed) Published
Abstract [en]

Lightweight iron oxide nanoparticle (IONP)/TEMPO-oxidized cellulose nanofibril (TOCNF) hybrid foams with an anisotropic structure and a high IONP content were produced using magnetic field-enhanced unidirectional ice-templating. Coating the IONP with tannic acid (TA) improved the processability, the mechanical performance, and the thermal stability of the hybrid foams. Increasing the IONP content (and density) increased the Young's modulus and toughness probed in compression, and hybrid foams with the highest IONP content were relatively flexible and could recover 14% axial compression. Application of a magnetic field in the freezing direction resulted in the formation of IONP chains that decorated the foam walls and the foams displayed a higher magnetization saturation, remanence, and coercivity compared to the ice-templated hybrid foams. The hybrid foam with an IONP content of 87% displayed a saturation magnetization of 83.2 emu g−1, which is 95% of the value for bulk magnetite. Highly magnetic hybrid foams are of potential interest for environmental remediation, energy storage, and electromagnetic interference shielding.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-218047 (URN)10.1039/d3ra01896b (DOI)000984061400001 ()37181513 (PubMedID)2-s2.0-85159295692 (Scopus ID)
Available from: 2023-07-26 Created: 2023-07-26 Last updated: 2024-02-21Bibliographically approved
Di, A., Schiele, C., Hadi, S. E. & Bergström, L. (2023). Thermally Insulating and Moisture-Resilient Foams Based on Upcycled Aramid Nanofibers and Nanocellulose. Advanced Materials, 35(48), Article ID 2305195.
Open this publication in new window or tab >>Thermally Insulating and Moisture-Resilient Foams Based on Upcycled Aramid Nanofibers and Nanocellulose
2023 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 35, no 48, article id 2305195Article in journal (Refereed) Published
Abstract [en]

Low-density foams and aerogels based on upcycled and bio-based nanofibers and additives are promising alternatives to fossil-based thermal insulation materials. Super-insulating foams are prepared from upcycled acid-treated aramid nanofibers (upANFA) obtained from Kevlar yarn and tempo-oxidized cellulose nanofibers (CNF) from wood. The ice-templated hybrid upANFA/CNF-based foams with an upANFA content of up to 40 wt% display high thermal stability and a very low thermal conductivity of 18–23 mW m−1 K−1 perpendicular to the aligned nanofibrils over a wide relative humidity (RH) range of 20% to 80%. The thermal conductivity of the hybrid upANFA/CNF foams is found to decrease with increasing upANFA content (5–20 wt%). The super-insulating properties of the CNF-upANFA hybrid foams are related to the low density of the foams and the strong interfacial phonon scattering between the very thin and partially branched upANFA and CNF in the hybrid foam walls. Defibrillated nanofibers from textiles are not limited to Kevlar, and this study can hopefully inspire efforts to upcycle textile waste into high-performance products.

Keywords
aramid nanofibers, foams, Kevlar, phonon scattering, thermal insulation, upcycling
National Category
Materials Chemistry
Identifiers
urn:nbn:se:su:diva-223889 (URN)10.1002/adma.202305195 (DOI)001087976800001 ()37735848 (PubMedID)2-s2.0-85174610762 (Scopus ID)
Available from: 2023-11-21 Created: 2023-11-21 Last updated: 2024-01-16Bibliographically approved
Di, A., Xu, J., Zinn, T., Sztucki, M., Deng, W., Ashok, A., . . . Bergström, L. (2023). Tunable Ordered Nanostructured Phases by Co-assembly of Amphiphilic Polyoxometalates and Pluronic Block Copolymers. Nano Letters, 23(5), 1645-1651
Open this publication in new window or tab >>Tunable Ordered Nanostructured Phases by Co-assembly of Amphiphilic Polyoxometalates and Pluronic Block Copolymers
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2023 (English)In: Nano Letters, ISSN 1530-6984, E-ISSN 1530-6992, Vol. 23, no 5, p. 1645-1651Article in journal (Refereed) Published
Abstract [en]

The assembly of polyoxometalate (POM) metal–oxygen clusters into ordered nanostructures is attracting a growing interest for catalytic and sensing applications. However, assembly of ordered nanostructured POMs from solution can be impaired by aggregation, and the structural diversity is poorly understood. Here, we present a time-resolved small-angle X-ray scattering (SAXS) study of the co-assembly in aqueous solutions of amphiphilic organo-functionalized Wells-Dawson-type POMs with a Pluronic block copolymer over a wide concentration range in levitating droplets. SAXS analysis revealed the formation and subsequent transformation with increasing concentration of large vesicles, a lamellar phase, a mixture of two cubic phases that evolved into one dominating cubic phase, and eventually a hexagonal phase formed at concentrations above 110 mM. The structural versatility of co-assembled amphiphilic POMs and Pluronic block copolymers was supported by dissipative particle dynamics simulations and cryo-TEM. 

Keywords
Amphiphilic polyoxometalate, Co-assembly, Ordered nanostructure, Catalysis
National Category
Physical Chemistry
Identifiers
urn:nbn:se:su:diva-215940 (URN)10.1021/acs.nanolett.2c03068 (DOI)000934883000001 ()36795963 (PubMedID)2-s2.0-85148945436 (Scopus ID)
Available from: 2023-03-29 Created: 2023-03-29 Last updated: 2023-05-11Bibliographically approved
Church, T. L., Kriechbaum, K., Schiele, C., Apostolopoulou-Kalkavoura, V., Hadi, S. E. & Bergström, L. (2022). A Stiff, Tough, and Thermally Insulating Air- and Ice-Templated Plant-Based Foam. Biomacromolecules, 23(6), 2595-2602
Open this publication in new window or tab >>A Stiff, Tough, and Thermally Insulating Air- and Ice-Templated Plant-Based Foam
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2022 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 23, no 6, p. 2595-2602Article in journal (Refereed) Published
Abstract [en]

By forming and directionally freezing an aqueous foam containing cellulose nanofibrils, methylcellulose, and tannic acid, we produced a stiff and tough anisotropic solid foam with low radial thermal conductivity. Along the ice-templating direction, the foam was as stiff as nanocellulose–clay composites, despite being primarily methylcellulose by mass. The foam was also stiff perpendicular to the direction of ice growth, while maintaining λr < 25 mW m–1 K–1 for a relative humidity (RH) up to 65% and <30 mW m–1 K–1 at 80% RH. This work introduces the tandem use of two practical techniques, foam formation and directional freezing, to generate a low-density anisotropic material, and this strategy could be applied to other aqueous systems where foam formation is possible. 

National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-206856 (URN)10.1021/acs.biomac.2c00313 (DOI)000811374000001 ()35621041 (PubMedID)
Available from: 2022-07-01 Created: 2022-07-01 Last updated: 2022-07-01Bibliographically approved
Héraly, F., Zhang, M., Åhl, A., Cao, W., Bergström, L. & Yuan, J. (2022). Nanodancing with Moisture: Humidity-Sensitive Bilayer Actuator Derived from Cellulose Nanofibrils and Reduced Graphene Oxide. Advanced Intelligent Systems, 4(1), Article ID 2100084.
Open this publication in new window or tab >>Nanodancing with Moisture: Humidity-Sensitive Bilayer Actuator Derived from Cellulose Nanofibrils and Reduced Graphene Oxide
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2022 (English)In: Advanced Intelligent Systems, E-ISSN 2640-4567, Vol. 4, no 1, article id 2100084Article in journal (Refereed) Published
Abstract [en]

Bilayer actuators, traditionally consisting of two laminated materials, are the most common types of soft or hybrid actuators. Herein, a nanomaterial-based organic–inorganic humidity-sensitive bilayer actuator composed of TEMPO-oxidized cellulose nanofibrils (TCNF-Na+) and reduced graphene oxide (rGO) sheets is presented. The hybrid actuator displays a large humidity-driven locomotion with an atypical fast unbending. Cationic exchange of the anionically charged TCNF-Na+ and control of the layer thickness is used to tune and dictate the locomotion and actuator's response to humidity variations. Assembly of a self-oscillating electrical circuit, that includes a conductive rGO layer, displays autonomous on-and-off lighting in response to actuation-driven alternating electrical heating.

Keywords
bilayer actuators, cellulose nanofibrils, humidity sensors, reduced graphene oxide, smart materials
National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-198677 (URN)10.1002/aisy.202100084 (DOI)000700058800001 ()
Available from: 2021-11-15 Created: 2021-11-15 Last updated: 2023-12-17Bibliographically approved
Ménard, D., Blaschek, L., Kriechbaum, K., Lee, C. C., Serk, H., Zhu, C., . . . Pesquet, E. (2022). Plant biomechanics and resilience to environmental changes are controlled by specific lignin chemistries in each vascular cell type and morphotype. The Plant Cell, 34(12), 4877-4896
Open this publication in new window or tab >>Plant biomechanics and resilience to environmental changes are controlled by specific lignin chemistries in each vascular cell type and morphotype
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2022 (English)In: The Plant Cell, ISSN 1040-4651, E-ISSN 1532-298X, Vol. 34, no 12, p. 4877-4896Article in journal (Refereed) Published
Abstract [en]

The biopolymer lignin is deposited in the cell walls of vascular cells and is essential for long-distance water conduction and structural support in plants. Different vascular cell types contain distinct and conserved lignin chemistries, each with specific aromatic and aliphatic substitutions. Yet, the biological role of this conserved and specific lignin chemistry in each cell type remains unclear. Here, we investigated the roles of this lignin biochemical specificity for cellular functions by producing single cell analyses for three cell morphotypes of tracheary elements, which all allow sap conduction but differ in their morphology. We determined that specific lignin chemistries accumulate in each cell type. Moreover, lignin accumulated dynamically, increasing in quantity and changing in composition, to alter the cell wall biomechanics during cell maturation. For similar aromatic substitutions, residues with alcohol aliphatic functions increased stiffness whereas aldehydes increased flexibility of the cell wall. Modifying this lignin biochemical specificity and the sequence of its formation impaired the cell wall biomechanics of each morphotype and consequently hindered sap conduction and drought recovery. Together, our results demonstrate that each sap-conducting vascular cell type distinctly controls their lignin biochemistry to adjust their biomechanics and hydraulic properties to face developmental and environmental constraints. 

National Category
Biological Sciences
Identifiers
urn:nbn:se:su:diva-210649 (URN)10.1093/plcell/koac284 (DOI)000922798100019 ()36215679 (PubMedID)
Available from: 2022-10-25 Created: 2022-10-25 Last updated: 2023-02-28Bibliographically approved
Munier, P., Hadi, S. E., Segad, M. & Bergström, L. (2022). Rheo-SAXS study of shear-induced orientation and relaxation of cellulose nanocrystal and montmorillonite nanoplatelet dispersions. Soft Matter, 18(2), 390-396
Open this publication in new window or tab >>Rheo-SAXS study of shear-induced orientation and relaxation of cellulose nanocrystal and montmorillonite nanoplatelet dispersions
2022 (English)In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 18, no 2, p. 390-396Article in journal (Refereed) Published
Abstract [en]

The development of robust production processes is essential for the introduction of advanced materials based on renewable and Earth-abundant resources. Cellulose nanomaterials have been combined with other highly available nanoparticles, in particular clays, to generate multifunctional films and foams. Here, the structure of dispersions of rod-like cellulose nanocrystals (CNC) and montmorillonite nanoplatelets (MNT) was probed using small-angle X-ray scattering within a rheological cell (Rheo-SAXS). Shear induced a high degree of particle orientation in both the CNC-only and CNC:MNT composite dispersions. Relaxation of the shear-induced orientation in the CNC-only dispersion decayed exponentially and reached a steady-state within 20 seconds, while the relaxation of the CNC:MNT composite dispersion was found to be strongly retarded and partially inhibited. Viscoelastic measurements and Guinier analysis of dispersions at the shear rate of 0.1 s(-1) showed that the addition of MNT promotes gel formation of the CNC:MNT composite dispersions. A better understanding of shear-dependent assembly and orientation of multi-component nanoparticle dispersions can be used to process materials with improved mechanical and functional properties.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-200553 (URN)10.1039/d1sm00837d (DOI)000729560900001 ()34901987 (PubMedID)
Available from: 2022-01-07 Created: 2022-01-07 Last updated: 2024-02-21Bibliographically approved
Bender, P., Wetterskog, E., Salazar-Alvarez, G., Bergström, L., Hermann, R. P., Brückel, T., . . . Disch, S. (2022). Shape-induced superstructure formation in concentrated ferrofluids under applied magnetic fields. Journal of applied crystallography, 55(6), 1613-1621
Open this publication in new window or tab >>Shape-induced superstructure formation in concentrated ferrofluids under applied magnetic fields
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2022 (English)In: Journal of applied crystallography, ISSN 0021-8898, E-ISSN 1600-5767, Vol. 55, no 6, p. 1613-1621Article in journal (Refereed) Published
Abstract [en]

The field-induced ordering of concentrated ferrofluids based on spherical and cuboidal maghemite nanoparticles is studied using small-angle neutron scattering, revealing a qualitative effect of the faceted shape on the interparticle interactions as shown in the structure factor and correlation lengths. Whereas a spatially disordered hard-sphere interaction potential with a short correlation length is found for ∼9 nm spherical nanoparticles, nanocubes of a comparable particle size exhibit a more pronounced interparticle interaction and the formation of linear arrangements. Analysis of the anisotropic two-dimensional pair distance correlation function gives insight into the real-space arrangement of the nanoparticles. On the basis of the short interparticle distances found here, oriented attachment, i.e. a face-to-face arrangement of the nanocubes, is likely. The unusual field dependence of the interparticle correlations suggests a field-induced structural rearrangement.

Keywords
ferrofluids, nanocubes, dipolar interactions, small-angle neutron scattering, magnetic SANS
National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-213416 (URN)10.1107/S1600576722010093 (DOI)000892394500021 ()36570658 (PubMedID)
Available from: 2023-01-04 Created: 2023-01-04 Last updated: 2023-01-04Bibliographically approved
Lv, Z.-P., Kapuscinski, M., Járvás, G., Yu, S. & Bergström, L. (2022). Time-Resolved SAXS Study of Polarity- and Surfactant-Controlled Superlattice Transformations of Oleate-Capped Nanocubes During Solvent Removal. Small, 18(22), Article ID 2106768.
Open this publication in new window or tab >>Time-Resolved SAXS Study of Polarity- and Surfactant-Controlled Superlattice Transformations of Oleate-Capped Nanocubes During Solvent Removal
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2022 (English)In: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 18, no 22, article id 2106768Article in journal (Refereed) Published
Abstract [en]

Structural transformations and lattice expansion of oleate-capped iron oxide nanocube superlattices are studied by time-resolved small-angle X-ray scattering (SAXS) during solvent removal. The combination of conductor-like screening model for real solvents (COSMO-RS) theory with computational fluid dynamics (CFD) modeling provides information on the solvent composition and polarity during droplet evaporation. Evaporation-driven poor-solvent enrichment in the presence of free oleic acid results in the formation of superlattices with a tilted face-centered cubic (fcc) structure when the polarity reaches its maximum. The tilted fcc lattice expands subsequently during the removal of the poor solvent and eventually transforms to a regular simple cubic (sc) lattice during the final evaporation stage when only free oleic acid remains. Comparative studies show that both the increase in polarity as the poor solvent is enriched and the presence of a sufficient amount of added oleic acid is required to promote the formation of structurally diverse superlattices with large domain sizes. 

Keywords
anisotropic nanoparticles, small angle X-ray scattering, superlattice transformation, time-dependent measurements
National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-204670 (URN)10.1002/smll.202106768 (DOI)000791543400001 ()35523733 (PubMedID)2-s2.0-85129362737 (Scopus ID)
Available from: 2022-05-20 Created: 2022-05-20 Last updated: 2022-06-10Bibliographically approved
Munier, P., Di, A., Hadi, S. E., Kapuscinski, M., Segad, M. & Bergström, L. (2021). Assembly of cellulose nanocrystals and clay nanoplatelets studied by time-resolved X-ray scattering. Soft Matter, 17(23), 5747-5755
Open this publication in new window or tab >>Assembly of cellulose nanocrystals and clay nanoplatelets studied by time-resolved X-ray scattering
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2021 (English)In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 17, no 23, p. 5747-5755Article in journal (Refereed) Published
Abstract [en]

Time-resolved small-angle X-ray scattering (SAXS) was used to probe the assembly of cellulose nanocrystals (CNC) and montmorillonite (MNT) over a wide concentration range in aqueous levitating droplets. Analysis of the SAXS curves of the one-component and mixed dispersions shows that co-assembly of rod-like CNC and MNT nanoplatelets is dominated by the interactions between the dispersed CNC particles and that MNT promotes gelation and assembly of CNC, which occurred at lower total volume fractions in the CNC:MNT than in the CNC-only dispersions. The CNC dispersions displayed a d proportional to phi(-1/2) scaling and a low-q power-law exponent of 2.0-2.2 for volume fractions up to 35%, which indicates that liquid crystal assembly co-exists and competes with gelation.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-195089 (URN)10.1039/d1sm00251a (DOI)000652676200001 ()34019065 (PubMedID)
Available from: 2021-08-06 Created: 2021-08-06 Last updated: 2022-02-25Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-5702-0681

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