Influence of surface tension in the surfactant-driven fracture of closely-packed particulate monolayers

摘要

A phase-field model is used to capture the surfactant-driven formation offracture patterns in particulate monolayers. The model is intended for theregime of closely-packed systems in which the mechanical response of themonolayer can be approximated as a linearly elastic solid. The modelapproximates the loss in tensile strength of the monolayer as the surfactantconcentration increases through the evolution of a damage field.Initial-boundary value problems are constructed and spatially discretized withfinite element approximations to the displacement and surfactant damage fields.A comparison between model-based simulations and existing experimentalobservations indicates a qualitative match in both the fracture patterns andtemporal scaling of the fracture process. The importance of surface tensiondifferences is quantified by means of a dimensionless parameter, revealingthresholds that separate different regimes of fracture. These findings aresupported by newly performed experiments that validate the model anddemonstrate the strong sensitivity of the fracture pattern to differences insurface tension.