Study of Micro- and Nanoscale Wetting Properties of Lubricants Using AFM Force–Distance Curves

Force–distance curves have been recorded on thin films of nine different lubricants to extend the results of a previous work of one of the authors. The lubricants wet the AFM tip, which causes a capillary force. This depends on the shape of the tip, as well as on properties of the lubricants such as surface tension, contact angle, and viscosity, which have been additionally measured with other methods. Thus, their influence on the shape of the curves could be analyzed. The main features of force–distance curves on different lubricants have been characterized and the underlying phenomena could be explained. Results contribute to a better understanding of fundamental mechanisms influencing lubrication and hence friction and wear at the micro- and nanoscale.