Surface and morphological characterization of polysiloxane-block-polyimides

Two series of polysiloxane-block-polyimides were synthesized by the method of solution imidization of the polyamic acids prepared from the dianhydride/diamine combinations of 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride (DSDA)/2,2-bis[4-(4-aminophenoxy) phenyl] propane (BAPP) (Series A) and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA)/bis[4-(3-aminophenoxy) phenyl] sulfone (BAPSM) (Series B) with three kinds of w-diamino-poly(dimethylsiloxane) with different number-average molecular weight added as a part of diamine. These polysiloxane-block-polyimides, having various compositions and chain lengths of the polysiloxane segments, were subjected to solution casting to prepare their films, and their surface and interface properties were analyzed by contact angle, XPS, AFM, and SEM. It was found that the surface tension and surface topography were greatly influenced by the composition and molecular weight of the polysiloxane segments because of their surface enrichment, which was affected by the environment and substrate with which the copolyimides had contacted. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2239–2251, 1997