Maghemite nanocrystal impregnation by hydrophobic surface modification of mesoporous silica
2007 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 23, no 17, 8838-8844 p.Article in journal (Refereed) Published
Here, we report the design of a hybrid inorganic/organic mesoporous material through simultaneous pore engineering and hydrophobic surface modification of the intramesochannels to improve the uptake of superparamagnetic maghemite nanocrystals via impregnation techniques. The mesoporous material of the SBA-15 type was functionalized in situ with thiol organo-siloxane groups. Restricting the addition of the thiol organo-siloxane to 2 mol % yielded an inorganic/organic hybrid material characterized by large pores and a well-ordered hexagonal p6mm mesophase. The hydrophobic surface modification promoted the incorporation of 7.5 nm maghemite (gamma-Fe2O3) nanocrystals, prepared through temperature-control led decomposition of iron pentacarbonyl in organic solvents. The hydrophobic, oleic acid capped superparamagnetic maghemite nanocrystals were incorporated into the porous network via wet impregnation from organic suspensions. Combining diffraction, microscopy, and adsorption data confirmed the uptake of the nanocrystals within the intramesochannels of the silica host. Magnetization dependencies on magnetic field at different temperatures show a constriction in the loop around the origin, which indicates immobilization of maghemite nanocrystals inside the thiol-functionalized silica host.
Place, publisher, year, edition, pages
2007. Vol. 23, no 17, 8838-8844 p.
molecular-sieves, semiconductor nanocrystals, magnetic nanocrystals, nonionic triblock, nanoparticles, sba-15, carbon, transformation, chemistry, catalysts
IdentifiersURN: urn:nbn:se:su:diva-55890DOI: 10.1021/la063395uISI: 000248730500035OAI: oai:DiVA.org:su-55890DiVA: diva2:407622
authorCount :52011-03-312011-03-302011-03-31Bibliographically approved