Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/318818
Type: research-article
Title: Structural Parameters of Lamellar Phases Formed by the Self-Assembly of Dialkyldimethylammonium Bromides in Aqueous Solution
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Author: Ferreira
Guilherme A.; Loh
Watson
Abstract: Phase behavior of didodecyl and dioctadecydimethylammonium bromide (DDAB and DODAB) in water was studied using X-ray techniques, differential scanning calorimetry and deuterium nuclear magnetic resonance measurements. Both surfactants self-assemble into lamellar liquid crystalline, either L? (fluid) and L? (gel), phases. The gel-to-fluid phase transition temperature (Tm) in DDAB lamellae was found to be higher than that observed for its vesicles, due to the formation of a stabilized gel phase. In addition, the lamellar phases formed by both amphiphiles differ in their swelling degree and bilayer thickness. DODAB in water formed rather thin bilayers, if compared with the length of the tails, suggesting effective chain interdigitation. These bilayers also presented higher swelling degree than those formed by the shorter-chain homologue DDAB. We propose that these structural properties are strongly influenced by the electrostatic repulsive forces acting on the system.
Rights: aberto
Identifier DOI: 10.5935/0103-5053.20150297
Address: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532016000200392
Date Issue: 2016
Appears in Collections:Unicamp - Artigos e Outros Documentos

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