Atomic force microscopy study of rubbed polyimide films

The surface of rubbed polyimide films was studied as a function of the film thickness and applied load using atomic force microscopy (AFM). Three dominant consequences of rubbing on the film topography were observed: scratches confined to the near surface of the film, tears that extended to the substrate, and strings of islands or droplets aligned parallel to the rubbing direction. Tears, found only in films less than 50 nm thick, varied in areal density and shape due to variations in the film thickness, rubbing load, and adhesion to the substrate. Strings of droplets aligned in the rubbing direction were seen on most samples without discernible dependence on the thickness or rubbing load. (C) 2001 John Wiley & Sons, Inc.