Statistical analysis of micro-domain ensembles at the surface of polyamic acid films during their conversion to polyimide

Abstract

The surface morphology of polyamic acid films evolving to polyimide films is investigated using transmission electron microscopy. Two methods of film conversion, thermal and chemical, are studied. The micro-domains at the surface of the films are shown to form thermodynamically optimised statistical ensemble(s) during polymer conversion. The statistical distribution of the micro-domain diameters is described utilising the model of reversible aggregation. The distribution parameters, aggregation energy and mean diameter of the micro-domains, are shown to depend on the chemical structure of the polymer, the method of conversion and, in the case of thermal conversion, the temperature at which the processing occurs.