Recent developments of surface light scattering as a tool for optical-rheology of polymer monolayers

Surface quasi-elastic light scattering (SQELS) is an application of dynamic light scattering to measure the dynamics of the thermal roughness of liquid surfaces. An analysis of the spectrum of thermal fluctuations provides information on surface properties like tension and elasticity. In this work we will focus particularly on its use to study polymer or polymer-like Langmuir monolayers. We review work in this area and give an up-to-date overview of the method. Important advances have very recently taken place in the theoretical understanding of this problem, and this has allowed improvements in the analysis of the experimental data. A practical method to estimate the region of physical parameters that can be reliably measured is presented.