Hydration-Induced Phase Transitions in Surfactant and Lipid Films

DSpace Repository

Hydration-Induced Phase Transitions in Surfactant and Lipid Films

Details

Files for download

Find Full text There are no files associated with this item..

Overview of item record
Publication Article, peer reviewed scientific
Title Hydration-Induced Phase Transitions in Surfactant and Lipid Films
Author Björklund, Sebastian ; Kocherbitov, Vitaly
Research Centre Biofilms - Research Center for Biointerfaces
Date 2016
English abstract
For several surfactant and lipid systems, it is crucial to understand how hydration influences the physical and chemical properties. When humidity changes, it affects the degree of hydration by adding or removing water molecules. In many cases, this process induces transitions between liquid crystalline phases. This phenomenon is of general interest for numerous applications simply because of the fact that humidity variations are ubiquitous. Of particular interest are hydration-induced phase transitions in amphiphilic films, which in many cases appear as the frontier toward a vapor phase with changing humidity. Considering this, it is important to characterize the film thickness needed for the formation of 3D liquid crystalline phases and the lyotropic phase behavior of this kind of film. In this work, we study this issue by employing a recently developed method based on the humidity scanning quartz crystal microbalance with dissipation monitoring (HS QCM-D), which enables continuous scanning of the film hydration. We investigate five surfactants films (DDAO, DTAC, CTAC, SDS, and n-octyl beta-D-glucoside) and one lipid film (monoolein) and show that HS QCM-D enables the fast characterization of hydration-induced phase transitions with small samples. Film thicknesses range from tens to hundreds of nanometers, and clear phase transitions are observed in all cases. It is shown that phase transitions in films occur at the same water activities as for corresponding bulk samples. This allows us to conclude that surfactant and lipid films, with a thickness of as low as 50 nm, are in fact assembled as 3D-structured liquid crystalline phases. Furthermore, liquid crystalline phases of surfactant films show liquidlike behavior, which decreases the accuracy of the absorbed water mass measurement. On the other hand, the monoolein lipid forms more rigid liquid crystalline films, allowing for an accurate determination of the water sorption isotherm, which is also true for the sorption isotherms corresponding to the solid surfactant phases.
DOI https://doi.org/10.1021/acs.langmuir.6b00452 (link to publisher's fulltext.)
Publisher ACS
Host/Issue LANGMUIR;21
Volume 32
ISSN 0743-7463
Pages 5223-5232
Language eng (iso)
Subject Chemistry, Multidisciplinary
Chemistry, Physical
Materials Science,
Multidisciplinary
Sciences
Research Subject Categories::NATURAL SCIENCES
Handle http://hdl.handle.net/2043/21874 Permalink to this page
Facebook

This item appears in the following Collection(s)

Details

Search


Browse

My Account

Statistics