Soft diffuse interfaces in electrokinetics - theory and experiment for transport in charged diffuse layers

Charged and uncharged soft interfaces are present in a variety of microfluidic and biological systems. The electrokinetic properties of these fixed-diffuse-charge systems are dependent on (1) the components of the working fluid, (2) the bounding surface of the diffuse charge layer, and (3) the chemical and mechanical properties of the film itself. Here, we describe recent and past literature to provide a framework for the interpretation of data, utilizing the electrokinetic coupling matrix, and a description of the experimental techniques relevant for microfluidic systems. In this work, we focus on experiments on, and models for, flat surfaces with constant film mass.