Coupled Chemical Reactions in Dynamic Nanometric Confinement: VI. Neutron Depth Profiling Studies of Nanofluidic Behaviour During Track Etching in Polymers

In recent papers it was shown (by current/voltage (I/V) recordings, Bode plots and Ion Transmission Spectrometry) that the formation of precipitates from solutions in swift heavy ion tracks in thin polymer foils, if coupled with polymer foil etching, eventually leads to the formation of membranes within the etched tracks. Such structures open promising perspectives for the creation of novel biosensors. In this paper we report on Neutron Depth Profiling (NDP) studies of samples where such coupled chemical reactions were initiated in the presence of Li+ and F- ions. Whereas I/V spectroscopy gave us clues about the different migration speeds of both Li+ and F- ions in latent and etched tracks, NDP revealed that Li was always most abundant at the etched track entrances, especially on the track side where the precipitation-forming ions are applied.