Muscle-Inspired, High-Bandwidth Ionic Actuators Enabled by Fibrillar Ion-Channel Engineering

Conventional Nafion-based ionic actuators suffer from hydration-dependent ion transport and a long-standing trade-off between ionic conductivity and mechanical stiffness, which fundamentally limits force generation and prevents stable high-frequency operation. Here, we introduce a PEG-silica hybridized ionic electroactive Nafion (Ps-iEN) that forms a continuous fibrillar ion-transport network, enhances interfacial ion dissociation, and suppresses ionic liquid induced matrix softening. This molecular architecture enables the simultaneous enhancement of ionic mobility and mechanical rigidity, thereby overcoming the intrinsic limitations of traditional Nafion systems. Actuators incorporating Ps-iEN exhibit higher blocking force at low driving voltages, maintain stable actuation up to 50 Hz, and demonstrate long-term operational durability exceeding 30,000 cycles. The optimized Ps(15)-iEN actuator further reproduces distinct frequency-dependent motion modes, corresponding to single-twitch, pulsed, and partially fused contractions in skeletal muscle, demonstrating muscle-inspired multi-frequency actuation. Together, these findings establish Ps-iEN as a robust, energy-efficient electrolyte platform for high-bandwidth artificial soft muscles, wearable haptic interfaces, and fiber-integrated soft robotic electronics.