A Phase Field Analysis of Thermomechanically Coupled Liquid Crystal Elastomers

A nonlinear phase field approach is developed to investigate micron scale liquid crystal structure evolution within an elastomer network. The polymer network is described by hyperelastic constitutive relations while a set of configurational forces are introduced to simulate the liquid crystals. A general theoretical framework is given which illustrates coupling between the liquid crystal domains and elastomer without introducing explicit phenomenological coupling constants. The model is implemented numerically using a finite element phase field approach. Problems involving thermal gradients are reviewed to illustrate bending behavior due to liquid crystal reorientation. This is shown to also have implications on photomechanical liquid crystal elastomers.