Temperature and Scattering Contrast Dependences of Thickness Fluctuations in Surfactant Membranes

Published

August 19, 2011

Author(s)

Michihiro Nagao

Abstract

Temperature and scattering contrast dependences of thickness fluctuations have been investigated using neutron spin echo spectroscopy in a swollen lamellar phase com- posed of nonionic surfactant, water, and oil. In the present study, two contrast condi- tions are examined; one is the bulk contrast, which probes two surfactant monolayers with an oil layer as a membrane, and the other is the film contrast, which emphasizes an individual surfactant monolayer. The thickness fluctuations, as enhanced dynam- ics to the bending fluctuations are observed in a similar manner from both contrast conditions. The thickness fluctuation amplitude is constant over the measured tem- perature range, including in the vicinity of the phase boundary between the lamellar and micellar phases at low temperature and the boundary between the lamellar and bicontinuous phases at high temperature. The damping frequency of the thickness fluctuations is well scaled using viscosity within the membranes at low temperature. On the other hand, in the vicinity of the phase boundary at high temperature, thick- ness fluctuations become faster with no changes in the mode amplitude.

Citation

Journal of Chemical Physics

Volume

135

Issue

7

Pub Type

Journals

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Keywords

surfactant, membrane, neutron spin echo, small-angle neutron scattering, dynamics

Citation

Nagao, M. (2011), Temperature and Scattering Contrast Dependences of Thickness Fluctuations in Surfactant Membranes, Journal of Chemical Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=908574 (Accessed December 6, 2024)