Chain dynamics of surfactants in mesoporous silica
2013 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, no 42, 18620-18626 p.Article in journal (Refereed) Published
Mesostructured porous materials possess unique surface, structural, and bulk properties that lead to important practical applications. By retaining structure-directing species in the product material, mesostructured organic-inorganic composites are obtained which are of broad interest for fundamental studies of confinement effects and surface interaction on structural and dynamic properties of organic molecules. In the present study, solid state dipolar C-13-H-1 NMR spectroscopy is applied to quantitatively characterize the conformational dynamics of organic surfactants in the mesostructured composite CTAB-MCM41. Such an approach does not require assumptions and adjustable parameters and reflects the changes in conformational dynamics without relying on specific motional models. The conformational dynamics of the surfactant confined in solid hexagonal arrays is compared to that in hexagonal aggregates formed in a concentrated aqueous solution. The study showed that in cylindrical pores of hexagonal mesoporous silica the order parameter gradually decreases towards the end of the chain. The degree of order and the order parameter profile is similar to that observed in hexagonal liquid crystalline phases. However, the mobility of segments close to the head group is more restricted compared to that in the mesophase, as the result of interaction with the solid silica interface.
Place, publisher, year, edition, pages
2013. Vol. 15, no 42, 18620-18626 p.
Solid-State Nmr, Heteronuclear Dipolar Couplings, Mesostructured Materials, Polarization Transfer, C-13 Nmr, Liquid-Crystals, Lipid-Bilayers, Fast Mas, Spectroscopy, Diffusion
Other Chemistry Topics
IdentifiersURN: urn:nbn:se:kth:diva-133672DOI: 10.1039/c3cp52562gISI: 000325728400034ScopusID: 2-s2.0-84885589136OAI: oai:DiVA.org:kth-133672DiVA: diva2:662715
FunderSwedish Research Council
QC 201311082013-11-082013-11-082015-02-25Bibliographically approved