Experimental setup. Diagram of the experimental setup used to measure the dynamic response of a microcantilever vibrating in close proximity to a PDMS surface. The cantilever vibration was driven (purple dashed line) and detected (red solid line) optically using two laser beams. Cantilever chips were fixed on the bottom of a cavity used to confine the water. A PDMS surface attached to a motorized linear stage was moved down towards the cantilever, while continuously acquiring resonance spectra using a lock-in amplifier. The setup was controlled by software written in openBEB and LabVIEW.