Exceptional Elasto‐Dielectric Properties in a Highly Flexible Dielectric Elastomer Composite: The Key Roles of Parallel Elastic Nanofibers

ABSTRACT Soft and stretchable dielectric elastomers (DEs) have garnered significant attention for their excellent electromechanical conversion properties, unlocking avenues for advanced sensors, actuators, and energy harvesters. However, while traditional rigid fillers can enhance dielectric properties, they inevitably degrade the mechanical compliance of the elastomer. This trade‐off makes it a great challenge to design DE composites that provide mechanical enhancement while preserving the parent matrix's elasto‐dielectric performance. Herein, a highly flexible and robust dielectric elastomer composite is synthesized by embedding a parallel‐aligned polyurethane nanofiber network (p‐TPU) into a polydimethylsiloxane (PDMS) matrix. The aligned fibers effectively reduce stress concentrations and improve durability, simultaneously raising dielectric permittivity. This hierarchical structure yields excellent elasto‐dielectric performance with an enhanced dielectric constant, a low Young's modulus, and superior fatigue resistance (stable after 100,000 cycles). Further, the composite‐based DE actuator (DEA) achieves great reliability and twice the actuation strain of pristine PDMS, while the corresponding DE generator (DEG) delivers an enhanced energy conversion efficiency, a 51% increase compared to pristine PDMS. This work provides a robust strategy for designing high‐performance, flexible dielectric elastomer composites.