STUDY OF STRESS-HARDENING AND FATIGUE OF POLYMER-COATINGS IN MARRING WITH A SCANNING PROBE MICROSCOPE

We have used a scanning probe microscope with a custom-made diamond ti p to mar a crosslinked polymeric coating surface with an increasing nu mber of scrapings at a fixed normal force in the same channel. The dep th of ditches was measured, and the morphology at the bottom of the di tches was examined after each scraping. It provides a direct experimen tal evidence for stress-hardening and surface fatigue of a polymeric c oating on the sub-micron scale when it undergoes marring.