On the contact line dynamics of three-phase fluids

We investigate a model of multiphase polymer solutions undergoing fluid flow, phase separation, and buoyancy forcing. The thermodynamically consistent model couples three-phase Cahn-Hilliard dynamics with the Navier-Stokes equations. While the two-phase case is well-understood, the possibility of three-phase contact lines introduces several complications. We build on recent work to derive a reduced model of interface and junction dynamics valid in the physically relevant limit of vanishing interfacial thickness. Multiple numerical benchmarks verify our reduced model. We emphasise the interesting new behaviour possible in three dimensions, and touch on possible applications to microfluidic manufacture of complex microparticles.