Multiframe Imaging of Micron and Nanoscale Bubble Dynamics

Here, we report on the direct sequential imaging of laser-induced cavitation of micron and nanoscale bubbles using Movie-Mode Dynamic Transmission Electron Microscopy (MM-DTEM). A 532 nm laser pulse (similar to 12 ns) was used to excite gold nanoparticles inside a similar to 1.2 mu m layer of water, and the resulting bubbles were observed with a series of nine electron pulses (similar to 10 ns) separated by as little as 40 ns peak to peak. Isolated nanobubbles were observed to collapse in less than 50 ns, while larger (similar to 2-3 mu m) bubbles were observed to grow and collapse in less than 200 ns. Temporal profiles were generally asymmetric, possibly indicating faster growth than collapse dynamics, and the collapse time scale was found to be consistent with modeling and literature data from other techniques. More complex behavior was also observed for bubbles within proximity to each other, with interaction leading to longer lifetimes and more likely rebounding after collapse.

Automated summary

We directly imaged the laser-induced cavitation of micron and nanoscale bubbles using Movie-Mode Dynamic Transmission Electron Microscopy (MM-DTEM). The collapse of isolated nanobubbles was observed to occur in less than 50 ns, while larger bubbles (approximately 2-3 μm) grew and collapsed in less than 200 ns. Bubbles in close proximity to each other exhibited more complex behavior, with longer lifetimes and a higher likelihood of rebounding after collapse.