3D Printable and Reconfigurable Liquid Crystal Elastomers with Light-Induced Shape Memory via Dynamic Bond Exchange.

3D printable and reconfigurable liquid crystal elastomers (LCEs) that reversibly shape-morph when cycled above and below their nematic-to-isotropic transition temperature (TNI ) are created, whose actuated shape can be locked-in via high-temperature UV exposure. By synthesizing LCE-based inks with light-triggerable dynamic bonds, printing can be harnessed to locally program their director alignment and UV light can be used to enable controlled network reconfiguration without requiring an imposed mechanical field. Using this integrated approach, 3D LCEs are constructed in both monolithic and heterogenous layouts that exhibit complex shape changes, and whose transformed shapes could be locked-in on demand.