Effect of charge on the mechanical properties of surfactant bilayers. Issue 46 (10th November 2016)

• Record Type: Journal Article
• Authors: Bradbury, Robert; Nagao, Michihiro
• Is Part Of: Soft matter. Volume 12:Issue 46(2016)
• Page Start: 9383
• Page End: 9390
• Publication Date: 2016-11-10
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c6sm01686c
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : Charge interactions are shown to impact the internal membrane dynamics of surfactant bilayers which are controlled by their mechanical properties. Abstract : Charge effects on the mechanical properties of surfactant bilayers have been measured, for a system with a low ionic strength, using small-angle neutron scattering and neutron spin echo spectroscopy. We report that, not only does increasing the surface charge density lead to greater structural ordering and a stiffening of the membrane, which is consistent with classical theory of charge effects on membranes, but also that the relaxation rate of the membrane thickness fluctuations decreases without affecting the fluctuation amplitude. From the relaxation rate we demonstrate, using recent theory, that the viscosity of the surfactant membrane is increased with surface charge density, which suggests that the amount of charge controls the diffusion behavior of inclusions inside the membrane. The present results confirm that the thickness fluctuation relaxation rate and amplitude are tuned independently since the membrane viscosity is only influencing the relaxation rate. This work demonstrates that charge stabilization of lamellar bilayers is not merely affected by intermembrane interactions and structural ordering but that intramembrane dynamics also have a significant contribution.