In situ small angle x-ray scattering measurements of the filling process of polyisobutylene and poly-ϵ-caprolactone in ion track etched polycarbonate nanopores

We present results of in situ measurements of the filling process of polymer melts in nanopores. After accurate characterization of the empty nanopores, they are filled with the hydrophobic polyisobutylene and the hydrophilic poly-epsilon-caprolactone. The filling process is investigated in situ with small angle x-ray scattering. The time-dependent scattering intensity is investigated with a model function based on the Lucas-Washburn equation for the filling process of liquids in cylindrical pores. The model function describes the data qualitatively well in terms of a t-dependency of the filling height, but deviates clearly from the expected quantitative values of the bulk material properties. Furthermore, the occurrence of a precursor film wetting the nanopore surface on a short time scale is observed.