Deformation Analysis of Bubble near Curved Elastic Wall for Developing Shock Wave DDS

This paper describes a fundamental investigation of a new shock wave application in a drug delivery system (DDS) using a microcapsule including a single gas bubble. In this study, to design effective disintegrated microcapsule using a microjet, bubble deformation by shock waves near a curved elastic wall, which is the model of this microcapsule, is observed in an optical shadowgraph system using a high-speed camera and analyzed by image processing. The results show that a bubble compresses after shock wave propagation and the minimum radius of the bubble decreases with its distance to the model wall. During its expansion, a bubble near the wall extends locally and sharply, and then collapses. This deformation speed is estimated of microjet speed. Deformation speed has the peak against the initial bubble position from the wall, and can be controlled by changing the kind of bubble gas, the position of the initial bubble, and the elasticity and curvature of the wall. Therefore, it is found that changing these parameters a microcapsule can control the degree of its disintegration.