Characterization of dents and grooves on polymer films using Scanning White Light Interferometry

Surface deformation inflicted on two different kinds of thin layered polymer films was investigated under static indentation and dynamic loading (plowing) at room temperature. Affecting the surface were polished spherical steel tips of 0.5-1.6 mm radii moving at 0.1-16.0 mm/s along the surface. A load of 2-5 N was applied on the tip normal to the surface. The surface response was measured with a scanning white light interferometer. The relation between groove parameters (width and depth) and the deformation tool velocity as well as the tip diameter and the applied load were obtained from white light interferometer scans. In order to cover a large groove area, a series of 3D groove profiles were stitched together with a piece of software. The profile of the entire groove was compared to friction data recorded by the scratching device. The dependence of groove parameters on the input parameters (tip radius, load force and velocity) indicates that white light interferometry can be used to determine mechanical properties such as 'scratchability' (abrasing resistance) of polymer surfaces without sample contact.