Droplet being squeezed between two transparent conductive electrodes to generate voltage
We have been investigating the usage of the change in surface area of droplets of water or hydrogel in contact with two conducting plates to act as an energy generator. Squeezing a droplet between electrodes can generate a potential difference by converting mechanical energy from vibrations into electrical energy. This harnesses high capacitance inherent to electric double layers and surface charging at polymer/water interfaces. A sensor has been shown to generate almost 1V (peak-to-peak) in response to a 250 micron deformation between 1-100 Hz. This has been published in Smart Materials and Structures.
Bode plot showing magnitude and phase response for a 250 micron amplitude signal with experimental data (red) overlaid on simulated results (blue), in terms of peak-to-peak volts per change in interfacial surface area of the top electrode.