Oscillating surfaces fueled by a continuous AC electric field

Recent developments in soft matter science provide options to add mobility and motility to polymer films and surfaces. Restrictively, the dynamics in these materials are modulated by a pulsated trigger and the route to autonomous dynamics is still a most intriguing challenge. Here, is the design of a self-sustaining oscillating surface is reported that is fueled by a continuous AC electric field without an intermittent on–off switch. The underlying principle is based on the polarity inversion over the poly(dimethyl siloxane) layer with a 10 nm thick silicon oxide top layer by an integrated tri-electrode structure connected to an alternating power source. In absence of the electric signal, the coating surface is flat. By applying an AC field, the surface corrugates into a sinusoidal morphology and starts oscillating to develop a continuous standing wave. Typically, the oscillation frequency is 0–5 Hz and the modulation depth is 150 nm. The topographical dynamics are analyzed in terms of viscoelastic materials properties and actuation kinetics and are supported by finite element calculations.