Controlled cavitation in lab‐on‐a‐chip systems

Abstract

Typically cavitation bubble dynamics is studied either in a free, liquid or close to rigid, free or flexible boundaries. Here, we report on a new experimental approach to study cavitation bubbles in confined geometries with sizes comparable to the cavitation bubble (20–100 μm). These fluid environments are fabricated in a polymeric material (PDMS, polydimethylsiloxane) using a conventional molding process from a silicon master (lab‐on‐a‐chip systems). The bubbles are generated by focusing pulsed laser light into the microfluidic systems filled with a light‐absorbing dye. The bubble dynamics is recorded stroboscopically and with high‐speed photography. We report on bubble dynamics in various geometries such as in triangular, square, and disk‐shaped structures. Additionally, we study a cavitation bubble‐based micropump, the effect of the channel width on jetting dynamics, and the interaction of the cavitation bubble on suspension cells. The fluid flow is easily visualized by adding microparticles into the liquid. The authors propose that this new experimental approach opens an interesting toolbox in cavitation research.