Fundamental study on the growth process of interfacial microbubbles in an air-supersaturated solution

Abstract

Interfacial microbubbles widely exist and play important roles in nature and industries, while their growth process remained unknown in many aspects. In this study, the interfacial microbubbles are created in an air-supersaturated solution utilizing a sudden drop of ambient pressure, and the effects of different influential parameters on the growth process of interfacial microbubbles were studied by a self-made observation system. The investigations confirmed that the growth process of interfacial microbubbles under all conditions had experienced three stages, including the floating stage, transition stage and expansion stage. The experimental results also show that the magnitude of depressurization amplitude, surface wettability, surface roughness, dissolved air content, and solution surface tension have significant effects on the nucleation and growth of interfacial microbubbles. In addition, the modified diffusion theoretical model of dissolved air was successfully used to predict the changes in contact angle and bubble radius for interfacial bubbles during the growth process.