Frequency dependent visco-elastic properties of a water nanomeniscus : an AFM study in Force Feedback Mode

Recently, using an Atomic Force Microscope and a single cantilever excited at different frequencies it was shown that water nanomeniscus can exhibit a transition in mechanical responses when submitted to stimuli above few tens of kHz. The use of a single cantilever to explore phenomena at frequencies far from the cantilever resonance frequency is not a common and well-established strategy, and because water meniscus are ubiquitous in nature, we have also studied the water meniscus mechanical response, the stiffness G' (N/m) and the dissipation G"(kg/s), as a function of frequency by using cantilevers with different resonance frequencies. These results, based on classic dynamical AFM technics, confirm the anomalous mechanical response of water nanomeniscus when stimulated at frequencies high enough.