Self-Adhesive Liquid Metal Channel Patch with Tip-Guided Conformal Coupling and Leakage Suppression for Skin Bioelectronics

Abstract

Skin-interfacing electrodes are essential for wearable bioelectronics, yet conventional gel- and dry-type electrodes often suffer from dehydration, poor skin conformity, irritation, and delamination during motion, limiting their long-term performance. Here, a self-attachable liquid metal channel (S-LMC) patch is presented that integrates open-bottom Galinstan microchannels and micropillar arrays, both featuring re-entrant geometries for enhances skin adhesion and leakage suppression. A via-hole interconnect enables direct vertical signal transmission, eliminating the need for bulky wiring and facilitating compact integration. The patch achieves strong, reusable skin adhesion (>60 kPa), low contact impedance (7.35 k Omega<middle dot>cm2 at 10 Hz), and minimal skin irritation. Compared to commercial Ag/AgCl gel electrodes, the S-LMC patch exhibits >5x lower impedance, >2x higher ECG signal fidelity (20.23 dB vs. 9.03 dB under motion), and >2.4x higher long-term adhesion after 7 days. Its re-entrant microarchitecture also improves Galinstan confinement, achieving >2x higher critical pressure for leakage. These features enable motion-resilient biosignal monitoring and scalable system integration, establishing the S-LMC patch as a promising platform for next-generation skin-conformal bioelectronic interfaces.