Force interactions between substrates and SPM cantilevers immersed in fluids

With the availability of equipment used in Scanning Probe Microscopy (SPM), researchers have been able to probe the local fluid–substrate force interactions with resolutions of pN using a variety of SPM cantilevers. When using such methods, it is essential to differentiate between contributions to the net force on the cantilever. Specifically, the interaction between the cantilever, substrate and fluid, quantified while generating force curves, are discussed and compared with theoretical models for squeeze-film effects and drag on the SPM cantilevers. In addition we have demonstrated a simple method for utilizing the system as a micro-viscometer, independently measuring the viscosity of the lubricant for each test.