Interface dynamics and phase transition during bubble growth in viscoelastic medium

摘要

We have studied interface of bubbles formed inside polydimethylsiloxane, a kind of biocompatible elastomer. Atomic force microscopy (AFM) and x-ray diffraction (XRD) were used to study the interface and structure. We have performed scaling analysis on two randomly picked bubbles of different diameters. These values show how the interface of bubble roughens at different scales. XRD studies show a definite bubble induced phase transition from crystal-like state to glasslike state. As the interface grows, one would expect that the interface would become smoother but we observed rougher interface. Roughness at macroscale is attributed to the oscillatory surface with wavelength of ～2 μm. At nanoscale, 100 nm~2 area AFM scan shows surface ripples which we attribute to nanoscale stress and frozen thermal fluctuations.