Anomalous increase in dielectric susceptibility during isothermal aging of ultrathin polymer films

Abstract

The aging dynamics of poly(2-chlorostyrene) (P2CS) ultrathin films with thicknesses less than 10 nm were investigated using dielectric relaxation spectroscopy. The imaginary part of the dielectric susceptibility ϵ″ for P2CS ultrathin films with a thickness of 3.7 nm increased with an increase in isothermal aging time, while this was not the case for P2CS thin films thicker than 9.0 nm. This anomalous increase in ϵ″ for the ultrathin films is strongly correlated with the presence of a mobile liquidlike layer within the thin films.