When a densely packed monolayer of hydrophobic particles is placed on the surface of a liquid, the particles interact through capillary bridges, leading to the formation of particle rafts. The macroscopic properties of these rafts reflect an interplay between fluid and solid mechanics, giving rise to novel physics. This interplay is relevant to a wide range of applications, from the synthesis of ‘‘liquid marbles’’ to the design of drug delivery systems to the stabilization of drops.
Researchers in the DCML have developed a novel phase-field model to capture the surfactant-driven formation of fracture patterns in particulate monolayers. The model is intended for the regime of closely-packed systems in which the mechanical response of the monolayer can be approximated as that of a linearly elastic solid. A comparison between model-based simulations and existing experimental observations indicates a qualitative match in both the fracture patterns and temporal scaling of the fracture process. The importance of surface tension differences is quantified by means of a dimensionless parameter, revealing thresholds that separate different regimes of fracture. These findings are supported by newly performed experiments that validate the model and demonstrate the strong sensitivity of the fracture pattern to differences in surface tension.
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References
- Peco C, Liu Y, Rhea C, Dolbow JE. Models and Simulations of Surfactant-Driven Fracture in Particle Rafts, International Journal of Solids and Structures, 2018
- Peco C, Chen W, Liu Y, Bandi MM, Dolbow JE, Fried E. Influence of surface tension in the surfactant-driven fracture of closely-packed particulate monolayers, Soft Matter 13, 5832-5841, 2017