Abstract

Starting from a scalar field theory with mass and momentum conservation (model H), splitting and self-propulsion of droplets will be described in this talk when terms, which do not respect the time-reversal symmetry, are added to the model H. A self-shearing instability is obtained if active contractile stress is added to the momentum conservation equation. This instability interrupts the growth of droplets by splitting them. The contractile active stress has the effect of reversing the sign of the effective tension which arrests the growth. In the second part of the talk, a mechanism to obtain self-propulsion of active droplets by modifying the model H will be described. These results will be used to rationalize recent experiments in active matter.