Inertial interface cavitation creates complex, flow-like structures within a soft solid

Abstract

BackgroundInertial cavitation near soft material interfaces generates highly asymmetric bubble dynamics, intense stress localization, and complex fluid-structure interactions. However, the subsurface deformation fields within soft solids remain poorly resolved due to limitations in ultrafast, full-field measurement techniques. ObjectiveThis study aims to quantify the spatiotemporal deformation of soft hydrogels during laser-induced inertial cavitation near a gel-water interface. MethodsWe integrate single-pulse laser-induced inertial cavitation, an embedded internal Digital Image Correlation (DIC) speckle patterning method, and DIC to resolve in situ, full-field subsurface kinematics at 1-2 million frames per second. ResultsAmong all the tested different non-dimensional stand-off distances, four distinct cavitation-interface interaction regimes are identified, spanning symmetric bulk-like oscillations to strongly asymmetric collapses accompanied by interface indentation, jet reversal, and bubble penetration. Full-field measurements reveal stagnation points, vortex-like deformation patterns, and large localized strains that depend on the non-dimensional bubble stand-off distance. ConclusionsThis work establishes an experimental framework for quantifying inertial cavitation dynamics near a compliant gel-water interface. Using ultrafast imaging and DIC, we captured full-field deformation, strain localization, and jet formation across a wide range of stand-off distances near gel-water interfaces.