Supramolecular Chalcogen-Bonded Shape Memory Actuators

Abstract

Supramolecular liquid crystal elastomers (LCEs) incorporating chalcogen bonds (ChBs) have been synthesized and investigated for shape memory and actuation properties. LCEs featuring strong Se⋯N ChBs (−40 to −43 kJ mol−1) exhibit both shape memory effects (SME) and reversible actuation, while those with weaker S⋯N ChBs (−32 to −34 kJ mol−1) do not. The Se⋯N-based LCEs transition from one-way to two-way SME after three days at room temperature, enabling programmable 2D/3D shape transformations and rewritable surface patterns. They also enable the fabrication of light-powered crawling robots as well as temperature-responsive knot-like actuators. These results highlight the critical role of the ChB strength and specificity in designing functional materials. Solid-state NMR, Raman spectroscopy, and density functional theory calculations provide further molecular-level insights into ChB interactions, laying the groundwork for advanced supramolecular actuators and shape-morphing LCEs.