Biomathematics Seminar: Mechanics with topological defects. How to develop a non-developable surface
29 October 2010 15:15 in CM107
Complex matter, for instance nematic elastomers and glasses, can change shape in response to order-changing stimuli: heat, light, pH, . . . They can also mechanically change by rotating their order. We review this remarkable convergence of molecular ordering and mechanics.
Topological defects in order mean that order change creates Gaussian curvature in initially flat sheets. We show how this arises via smooth, stretch-free states. Defects of various topological charges, or multi-defect systems, are perhaps routes to reversibly creating arbitrary surfaces with any desired curvature simply by the flash of a light.
Applications are perhaps to micro and nano machines, micro-positioning and actuation, and also to microfluidics and processing.
Several fundamental questions remain unaddressed about the connection between topological defects and curvature, and the compatibility of sheets with metrics changed by these order-driven distortions.