High-Frequency Surface Dynamics at an Electroactive Polymer Producing Underwater Soundwaves

Coatings with dynamic surface structures are appealing to many applications like haptics and soft robotics. Restrictively, the speed of the surface dynamics in these coatings is often limited to frequencies below 1 kHz, which makes them unsuitable for applications like acoustics and communication optics. This work describes a method to create high-frequency surface dynamics controlled by alternating electric fields on a substrate-contact-modulated coating that consists of an elastic poly(dimethyl siloxane) network supported by SU-8 microstructures. The principle is based on the global application of Maxwell stress that is locally resisted by the supporting SU-8 microstructures. Inbetween the microstructures the elastic material is stretched, causing a large deformation of the surface topography, which is supported by the authors' finite element method models. By applying a high-frequency alternating field, they discovered resonance effects at frequencies up to 230 kHz, where the surface of the coating vibrates at high speeds and large amplitudes. At these high frequencies, the coatings can produce and detect ultrasound waves underwater, indicating their potential for ultrasound transducers in the future.

Automated summary

This study presents a method to create coatings with high-frequency surface dynamics controlled by alternating electric fields. By combining an elastic poly(dimethyl siloxane) network and SU-8 microstructures, the authors achieved resonance effects at frequencies up to 230 kHz, enabling the coatings to produce and detect ultrasound waves underwater. This research demonstrates the potential of these coatings for future ultrasound transducers.