Liquid Crystal Elastomer Lattices with Thermally Programmable Deformation via Multi-Material 3D Printing

An integrated design, modeling, and multi-material 3D printing platform for fabricating liquid crystal elastomer (LCE) lattices in both homogeneous and heterogeneous layouts with spatially programmable nematic director order and local composition is reported. Depending on their compositional topology, these lattices exhibit different reversible shape-morphing transformations upon cycling above and below their respective nematic-to-isotropic transition temperatures. Further, it is shown that there is good agreement between their experimentally observed deformation response and model predictions for all LCE lattice designs evaluated. Lastly, an inverse design model is established and the ability to print LCE lattices with the predicted deformation behavior is demonstrated. This work opens new avenues for creating architected LCE lattices that may find potential application in energy-dissipating structures, microfluidic pumping, mechanical logic, and soft robotics. Liquid crystal elastomer (LCE) lattices with thermally programmable deformation are designed, printed, and modeled. These lattices contain struts consisting of one of two LCE materials with disparate thermal actuation response. When heated, these architected lattices exhibit programmable deformation sequences predicted by a temperature-dependent quasi-static spring model. Using inverse design, soft architected lattices with arbitrary deformations are realized.image