We propose specular NR measurements on PEDOT films exposed to a novel room temperature ionic liquid, the deep eutectic solvent Propaline. The fundamental interest is that PEDOT redox switching (¿doping¿) in this medium shows a very unusual mechanism for electroneutrality maintenance: cation expulsion from the film followed by a sharp transition to anion entry. This implies a reservoir of ionic liquid in the film, whose scale and spatial distribution are unknown. It also raises the possibility of spatially segregated layers in the film, each with a single ion transfer mechanism, rather than a homogeneous structure with a mixed mechanism. While electrochemical techniques provide the net charge transfer characteristics and gravimetric acoustic wave (QCM) measurements can distinguish changes in ion populations, only NR can provide absolute ion populations and their spatial distributions.