In situ real time nanowear testing method of optical functional thin films

In the present work, we propose a new approach allowing for the in-situ real time observation of wear mechanisms of optical thin films on the nanoscale. The nanowear tests were performed using the scanning probe imaging and 2D monitoring capabilities of a depth-sensing nanoindenter. By recording the topographic and coefficient of friction (COF) images, it is possible to retrace the history of the wear track in real time. This method allows one to distinguish between different stages of wear related to different mechanisms (running-in, abrasive wear, and surface fatigue). This new approach is illustrated for a SiO2 thin film deposited onto a plastic substrate. The proposed methodology can be generalized and applied to a wide variety of functional and tribological systems.