2025/06/23 by Jacopo Romano, Romano, Jacopo, Ramin Golestanian +3 · 2 citations
Materials Science · Engineering · Earth and Planetary Sciences · #Solidification and crystal growth phenomena #Fluid Dynamics and Thin Films #nanoparticles nucleation surface interactions
paper · pdf · doi:10.48550/arxiv.2506.19029
We derive effective equations of motion governing the dynamics of sharp interfaces in phase-separated binary mixtures driven by spatio-temporal modulations of their material properties. We demonstrate, in particular, that spatial heterogeneities in the surface tension induce an effective capillary force that drives the motion of interfaces, even in the absence of hydrodynamics. Applying our sharp interface model to quantify the dynamics of thermophoretic droplets, we find that their deformation and transport properties are controlled by a combination of bulk and capillary forces, whose relative strength depends on droplet size. Strikingly, we show that small thermophobic droplets -- composed of a material with a positive Soret coefficient -- can spontaneously migrate towards high-temperature regions as a result of capillary forces.