Acylsemicarbazide‐Based Supramolecular Liquid Crystal Elastomers: from Molecular Design to Melt‐Processing Actuators

Abstract Liquid crystal elastomers (LCEs) are promising soft actuators, yet conventional covalently crosslinked systems typically suffer from limited reprocessability and reprogrammability. Here, supramolecular LCEs (SLCEs) are reported that incorporate acylsemicarbazide (ASC) moieties as dynamic hydrogen‐bonded crosslinks within a linear polyurethane‐urea backbone. Using a simple two‐step polymerization, hydrogen bond density and strength are systematically modulated by varying the hard‐segment content (18.3–26.9 wt.%) and ASC chain‐extender structure, respectively, resulting in SLCEs with tunable thermal, mechanical, and actuation responses. The maximum work capacity reaches 260 kJ m − 3 , more than twice that of previously reported hydrogen‐bonded SLCEs, and replacing an aliphatic dihydrazide chain extender with terephthalic dihydrazide yields an actuation strain of 72%, among the highest reported for SLCEs. The dynamic network also enables scalable fabrication of actuators with programmable deformation through melt extrusion and injection molding at moderate temperatures (<120 °C). In addition, these materials demonstrate robust self‐healing and recyclability. This generalizable molecular design combines high actuation performance with thermoplastic‐like processability, opening opportunities for sustainable, reprocessable soft actuators.