Nanomechanical mapping of soft matter by bimodal force microscopy

Bimodal force microscopy is a dynamic force-based method with the capability of mapping simultaneously the topography and the nanomechanical properties of soft-matter surfaces and interfaces. The operating principle involves the excitation and detection of two cantilever eigenmodes. The method enables the simultaneous measurement of several material properties. A distinctive feature of bimodal force microscopy is the capability to obtain quantitative information with a minimum amount of data points. Furthermore, under some conditions the method facilitates the separation of the topography data from other mechanical and/or electromagnetic interactions carried by the cantilever response. Here we provide a succinct review of the principles and some applications of the method to map with nanoscale spatial resolution mechanical properties of polymers and biomolecules in air and liquid.