Liquid-Cell TEM Study of Nanobubble Growth Kinetics and Dynamics in Ethanol

Abstract

Micrometer- and nanobubbles have gained increasing attention due to their effectiveness in enhancing gas-liquid phase processes. However, the growth behavior and dynamic driving forces governing nanobubbles remain difficult to probe experimentally at the nanoscale. In this study, in-situ liquid cell transmission electron microscopy (TEM) was employed to directly observe the real-time growth and evolution of nanobubbles in ethanol containing polymer. Under a certain level of electron beam irradiation, nanobubble nucleation at the solid-liquid interface was observed, along with subsequent growth, merger, and dissolution processes. By combining Fresnel fringe contrast analysis with statistical measurements, the kinetic factors governing nanobubble growth were examined. The results indicate that nanobubble growth is driven by the interplay between internal-external pressure differences and diffusion of solvated gas molecules, while bubble-bubble interactions and size disparities primarily modulate the manifestation of these driving forces. These observations provide a comprehensive understanding of nanobubble growth, interaction, and instability under liquid-cell TEM conditions, and offer experimental insights relevant to future nanobubble-based studies and applications.