Issue 43, 2013

Interaction of adsorbed polymers with supported cationic bilayers

Abstract

The interaction forces between bilayers of the cationic surfactant di(tallow ethyl ester)dimethyl ammonium chloride (DEEDMAC) were measured using a Surface Forces Apparatus (SFA) with and without an adsorbing polymer, polyacrylamide (PAM). In the absence of PAM, the forces measured between the bilayer surfaces were purely repulsive on approach and separation and is charge regulated. Addition of PAM induced structural changes to the bilayer interfaces, and resulted in the formation of bilayer-like patches of DEEDMAC decorated PAM (hydrated) on the mica surface. The interaction potential between these surfaces showed a modified DLVO interaction with an additional monotonic steric hydration repulsion on approach with an exponential force decay length of Dsteric ∼ 1 nm consistent with the measurements of hydration forces. On separating the surfaces, interdigitated polymers bridge between the two surfaces, resulting in a weak adhesion (adhesion energy, W0 ∼ 0.1 mJ m−2). Our results provide a picture of the complex molecular structure and interactions between uncharged adsorbing water soluble polymers and supported charged bilayers, and highlight the effects of adsorbing polymers on the structure of bilayers. Implications for the stability of vesicles in dispersions have been also discussed.

Graphical abstract: Interaction of adsorbed polymers with supported cationic bilayers

Supplementary files

Article information

Article type
Paper
Submitted
10 Jul 2013
Accepted
21 Aug 2013
First published
22 Aug 2013

RSC Adv., 2013,3, 20405-20411

Interaction of adsorbed polymers with supported cationic bilayers

S. Das, S. H. Donaldson Jr., Y. Kaufman and J. N. Israelachvili, RSC Adv., 2013, 3, 20405 DOI: 10.1039/C3RA43500H

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