Passive self-cleaning surfaces have been studied for a long time. The studies have mostly concentrated on rough superhydrophobic and superoilyphobic surface properties. Here demonstrate an active self-cleaning strategy for flat surfaces. We introduce a 20 MHz-frequency surface acoustic wave (SAW) in a solid substrate to render its surface self-cleaning. The SAW, propagating near a surface of a solid substrate, redirects the deposition of precipitating mass onto a nearby surface. In our experiment, we confine a solution of polymethylmethacrylate (PMMA) polymer and a volatile toluene solvent between two substrates. In the absence of SAW, we design the experiment so that, following the evaporation of the solution, most of the polymer deposits on the underlying substrate. The application of a propagating SAW in the latter substrate – designed to support the mechanical wave – mitigates the deposition of polymer on its surface. Instead, the polymer precipitate deposits on the upper inert substrate. Above a SAW power threshold, the polymer appears to deposit solely on the upper substrate, leaving the surface of the underlying substrate devoid of polymer mass. Hence, the presence of the SAW gives an active mean to avoid mass deposition on sensitive substrates by employing nearby sacrificial surfaces which serve as sinks to the deposit.

Surface acoustic wave mitigation of precipitate deposition on a solid surface – an active strategy for self cleaning surfacs

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.