A Stretchable, Mechanically-Interlocked Polyrotaxane Hydrogel for Wearable Motion and Electrophysiological Monitoring.

Many conductive hydrogels have been developed for wearable electronics; however, it remains a challenge to achieve simultaneous mechanical robustness, stable electrical properties, and tissue-compliant interfaces. Herein, we report a mechanically interlocked polyrotaxane hydrogel prepared via one-pot photopolymerization. The designed network integrates the energy-dissipative "pulley effect" of sliding macrocycles with a stable covalent network. The resulting hydrogel exhibits skin-like softness (modulus ∼8.5 kPa), ultrahigh stretchability (2450%), strong adhesion, and high ionic conductivity (7.46 mS/cm). It functions as a durable strain sensor with a broad sensing range and stable cyclic performance over 10 000 cycles. As an epidermal electrode, it acquires high‑fidelity electrocardiogram (ECG) and electromyogram (EMG) signals with a superior signal‑to‑noise ratio (>42 dB), even during motion, and maintains high signal quality over 24 h. Furthermore, a wearable five‑sensor array demonstrates its capability for real‑time gesture recognition and wireless robotic control. This work provides a robust and multifunctional material platform for advanced wearable bioelectronics.