In Situ Photopolymerization of Smectic B Liquid‐Crystalline Electrolytes from Mesogenic Phosphate–Diacrylate/Ionic Liquid Complexes for High‐Performance Soft Ionic Actuators

Nanostructured liquid‐crystalline (LC) electrolyte membranes hold significant promise for achieving both efficient ion transport and mechanical robustness—key requirements for high‐performance ionic actuators. Here, we report an in situ photopolymerization strategy to fabricate flexible electrolyte membranes composed of highly ion‐conductive LC complexes formed from a mesogenic phosphate and a photopolymerizable LC diacrylate, complexed with the ionic liquid EMImTFSI. The blend self‐assembles into a smectic B (SmB) phase, forming two‐dimensional (2D) ionic conduction pathways that are retained after polymerization. The resulting membrane, in which LC electrolytes are embedded within a photocured polymer matrix, exhibits ionic conductivity (10 −4 S cm −1 ) at room temperature and excellent mechanical flexibility. When integrated with PEDOT:PSS film electrodes, the actuator demonstrates a peak‐to‐peak bending strain of 1.11% under ±3 V at 0.01 Hz and maintains a displacement of 6 μm at 150 Hz. A blocking force of 1.6 mN is recorded at ±3 V and 0.1 Hz, outperforming previously reported actuators of larger size. The actuator also demonstrates outstanding durability, with bending strain increasing to 159% of its initial value after 50,000 actuation cycles. This work presents a simple and effective strategy for creating high‐performance nanostructured electrolytes, paving the way for next‐generation soft actuators for robotics.