Chapter 4 - Surface mechanical measurements at the nanoscale

Abstract

Recently, a number of instruments have been developed that allow researchers to probe adhesive interactions and mechanical properties of surfaces with nanoscale force, displacement, and spatial resolution. These instruments fall into two general categories: atomic force microscopy (AFM) and depth-sensing nanoindentation Both techniques employ spring-based systems to evaluate force displacement relationships between a probe (tip) and a sample surface; AFM and some nanoindenters provide imaging through topographic mapping of the sample with nanometer-scale resolution. AFM and depth-sensing nanoindentation instruments provide researchers with many capabilities for studying materials and interfacial properties using both quasi-static and dynamic testing. While these tools are relatively mature (one to two decades), techniques and applications are still rapidly evolving as their usage by scientists in different disciplines widens. Similar techniques have evolved enabling both types of instruments to measure contact stiffness, providing a way to monitor the size of these sub-optical limit contacts during the experiments. Evolution also continues through the new capabilities offered by combining instrumentation for depth-sensing indentation, scanning probe microscopy or dynamic measurements, which can provide powerful new capabilities to quantitatively map dynamic mechanical properties and adhesion.