Persistent internal polarizations in poly(ethylene terephthalate) films. V. Pitting

Abstract

Asperities have been found on the surfaces of commercial poly(ethylene terephthalate) films. These are the protruding sections of gel particles embedded in the bulk polymer. Because they are weaker than the surrounding bulk polymer, they may be collapsed, between grounded pressure electrodes, into C-and S-shaped pits. A statistical analysis of the number of pits formed per unit area, as functions of pressure, pressure application time, and sample preparation, has indicated that structural changes occur in both bulk polymer and asperities, and that these establish the asperity-pit relationship.