How the Texture Density Affect Dynamics of a Single Acoustic Cavitation Bubble Near a Skin-Like Wall in Sonophoresis Applications

For better applications of low-frequency sonophoresis in transdermal interstitial fluid extraction and transdermal drug delivery, the microscopic mechanism of skin permeabilization by low-frequency sonophoresis have drawn much attention. In the present work, influence of skin texture density on a single cavitation bubble in an ultrasonic field is studied. A novel experimental system based on high-speed photography has been designed to investigate the temporary evolution of single bubble near skin-like walls with different texture densities exposed to a 20.51kHz ultrasound in liquids. In addition, the dynamic characteristics of single bubbles near skin-like walls with different texture densities are analyzed. It is found that the influences of the texture density on the bubble dynamics are obvious, which reflect on the changes in the maximum size of the bubble margin during bubble oscillating and the moving speed of the bubble to the wall, as well as the collapse time and the jet speed during collapses, especially for the bubble with an ultra-high texture density. These effects of the texture density on the bubble dynamics can explain the mechanism of skin texture structure for promoting acoustic cavitation in related application fields.