New insights into sono-exfoliation mechanisms of graphite: In situ high-speed imaging studies and acoustic measurements

The application of ultrasound and acoustic cavitation in liquid exfoliation bulk layered materials is a widely used method. However, despite extensive research, the fundamental mechanisms remain far from being fully understood. A number theories have been proposed to interpret interactions between hence explain assisted exfoliation. Unfortunately, most research reported date ambiguous or inconclusive due lack direct real-time experimental evidence. In this paper, we report systematic work characterising emissions observing graphite situ, deionised water under dynamic interaction with laser induced bubbles. Using ultra-high-speed optical imaging, were able determine sequence events on time scale never before. Real-time observations also revealed that shock waves pressure magnitude up 5 MPa liquid-jets range 80 ms?1, transient bubble implosions, essential for initiation propagation process. On other hand, oscillations associated stable beneficial promoting gentler delamination layers.