Dynamics of bulk fluctuations in a lamellar phase studied by coherent x-ray scattering

TL;DR

This study uses x-ray photon correlation spectroscopy to analyze layer fluctuations in a lamellar phase, determining elastic constants and viscosity, and validating the technique against light-scattering data.

Contribution

It demonstrates the effectiveness of coherent x-ray scattering in measuring dynamic properties of lamellar phases, providing a new approach for characterizing ordered soft matter systems.

Findings

Measured relaxation rates of in-plane fluctuations

Determined elastic constants and viscosity of the lamellar phase

Validated x-ray scattering technique against light-scattering data

Abstract

Using x-ray photon correlation spectroscopy, we studied the layer fluctuations in the lamellar phase of an ionic lyotropic system. We measured the relaxation rate of in-plane (undulation) fluctuations as a function of the wave vector. Static and dynamic results obtained during the same experiment were combined to yield the values of both elastic constants of the lamellar phase (compression and bending moduli) as well as that of the sliding viscosity. The results are in very good agreement with dynamic light-scattering data, validating the use of the technique in ordered phases.