Suppression of curvature in nematic elastica

Abstract

Nematic elastic bodies can develop a gradient of response to heat, light and other stimuli. They then bend and develop curvature in a complex manner. Using the results for a general weak response derived in the preceding paper, we solve for strong spontaneous distortion where bend in one direction causes stretch in another direction if that too is bending, and vice versa. Since stretch is elastically expensive, it can cause suppression of one of the bends (we determine which), thus eliminating Gaussian curvature. This is the spontaneous distortion equivalent of the classical Lamb calculation of the anti-clastic suppression when large distortions are imposed in classical elastica. In practice, spontaneously deforming nematic solids, e.g. in actuation, are in this strong bend limit.