The very simple and cost-effective elastomer-based device is made up of a layer of microstructured dielectric elastomer (polydimethylsiloxane or PDMS) sandwiched between two PET films each sporting an indium tin oxide (ITO) electrode. The microstructures consist of pyramidal shapes obtained from casting the uncured elastomer solution into an inverted pyramid silicon mold (fabricated via an anisotropic wet etching technique).
Applying a biased positive sinusoidal voltage across the ITO electrodes compresses the microstructures, subject to the coulomb forces and electrostatic attraction. As the amplitude of the biased sinusoidal voltage decreases, the microstructures return to their original shape (through elastic force) and generate a perceivable reaction force in the thickness direction.
In a paper titled "High-pressure endurable flexible tactile actuator based on microstructured dielectric elastomer" published in Applied Physics Letters, the researchers explain that for a given pyramid height, the compressibility of the actuator can be tuned, as well as its resonance frequency by changing the interspacing between the micro-pyramids.