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Effect of Dissolved Polymer on the Elasticity and Plasticity of a Lyotropic Lamellar Mesophase
Author(s) -
Herrmann Laure,
Kékicheff Patrick
Publication year - 2016
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.201400175
Subject(s) - materials science , aqueous solution , polymer , mesophase , lamellar structure , chemical engineering , dissolution , elastic modulus , mica , lyotropic , composite material , liquid crystal , chemistry , organic chemistry , liquid crystalline , optoelectronics , engineering
Summary Using the Surface Force Apparatus (SFA) technique, direct force–distance measurements between mica surfaces immersed in a polymer‐doped lamellar phase are presented. In the aqueous layers separating the charged and undulating bilayers of sodium dodecyl sulfate (SDS)/octanol, water is replaced by a polyethylene glycol aqueous solution (PEG, M w ∼ 20000 g/mol). As the mesophases align with the layers parallel to the solid mica surfaces the measurements yield structural information on the confined mesophases as well as bulk elastic properties. Keeping the membrane volume fraction constant the PEG dissolution results in a marked decrease in the elastic compressibility modulus,B ¯ . This indicates a softening of the repulsive interactions between the lamellae mediated by polymer adsorption on the bilayers/aqueous solution interface. Insights into the behavior of the mesophases in confined geometries and thereby their stabilization mechanism are gained by noting a plastic contribution due to the presence of edge dislocations in the wedge‐like confinement geometry.