Interfacial glass transition profiles in ultrathin, spin cast polymer films

Abstract

Shear-modulated scanning force microscopy was used for the investigation of the effect of spin casting on the glass transition of amorphous atactic polystyrene films. The transitions measured as a function of film thickness, molecular weight and crosslinking density were found to deviate nonmonotonically. Based on the combined effects of shear-induced structuring and thermally activated interdiffusion the observed rheological anisotropy was interpreted. The results show that crosslinking the precast films elevate the glass transition values but have no effect on the spatial length scale.