Temperature-Triggered Adhesive Bioelectric Electrodes with Long-Term Dynamic Stability and Reusability.

Abstract

Bioelectric electrodes with low modulus and high adhesion have been intensively pursued, as they afford conformal and strong bonding at skin-electrode interface to improve the fidelity and stability of electrophysiological signals. However, during detachment, tough adhesion can cause pain or skin allergy; worse still, the soft electrodes can suffer damage due to excessive stretch/torsion, hampering long-term, dynamic, and multiple uses. Herein, a bioelectric electrode is proposed by transferring silver nanowires (AgNWs) network to the surface of bistable adhesive polymer (BAP). The phase transition temperature of BAP is tuned to be slightly below skin temperature at 30 °C. Triggered by skin heat, the BAP electrode achieves low modulus and high adhesion within seconds, allowing robust skin-electrode interface under dry, wet, and body-moving conditions. Ice bag treatment can dramatically stiffen the electrode and reduce the adhesion, which allows painless detachment and avoids electrode damage. Meanwhile, the AgNWs network with biaxial wrinkled microstructure remarkably promotes the electro-mechanical stability of the BAP electrode. The BAP electrode successfully combines long-term (7 days) and dynamic (body movements, sweat, underwater) stability, reusability (at least ten times), and minimized skin irritation during electrophysiological monitoring. The high signal-to-noise ratio and dynamic stability are demonstrated in the application of piano-playing training.