Scratch visibility analysis of polymer samples with an optical microscope

Determination of scratch and mar performance is important for any application where maintaining surface integrity is important, ranging from coated surfaces to bulk polymers or composites. In this paper we outline a new and systematic empirical method for scratch visibility analysis with an optical microscope. Like many existing methods to quantify the visibility of surface scratches, it relies on differences in the intensity of light reflected off a scratch and an unscratched control area. We show that these differences may not always correlate with perceived scratch visibility and develop a method to overcome this limitation. Our method can be implemented using standard optical microscope technology and delivers reproducible, quantitative results. Results for five proprietary latex coatings are in good agreement with a qualitative scratch visibility assessment.