Liquid Metal-Enhanced Highly Adhesive Electrodes for Multifunctional Epidermal Bioelectronics

Abstract

Liquid metal (LM) bioelectronics find widespread uses in healthcare devices and medical implants. However, the current LM-based electrodes suffer from achieving a combination of features including stable conductivity, high tissue adhesion, stability, good biocompatibility, degradability, and recyclability. In this work, a stable LM electrode is prepared with an extremely high adhesion strength (8.9 MPa), which is tunable in a wide range by introducing an adhesive ureidopyrimidinone (UPy)-based polymer to harvest the abovementioned properties. With the help of dynamic LM particle-polymer interactions in the polymer matrix, LMs can not only enhance the adhesion properties but also form a percolated network at a low LM loading (38 vol%) to achieve a high conductance stability (R/R0 = 0.76 at 100% strain). The high adhesion strength provides a highly stable electrical connection with rigid components with a high stretchability of 1154% when mounting a resistor, while a relatively low adhesion makes it a comfortable wounded skin-interfaced electrode for accelerating wound healing. Taking advantage of their tunable surface adhesion and biocompatibility, the as-prepared LM electrodes provide a more reliable and friendly approach to the development of healthcare devices.