Expandable, serpentine Au nanotrough networks for skin-like electrodes with superior thermal and moisture stability

Abstract

Flexible and stretchable electrodes as the cornerstone of bioelectronics are bridging human with biomedical devices in an unprecedentedly intimate and safer way. However, maintaining high electrical properties while adapting to moist, complex and dynamic biosurfaces for a prolonged period of usage remains a great challenge. Herein, we demonstrate an omnidirectionally stretchable transparent electrode based on serpentine Au nanotrough (AuNT) networks with highly tunable optoelectronic performances (sheet resistance of down to ∼13 Ω sq−1 at transmittance of 90%). Owing to the junction-free nanoweb structure with an ultralow percolation density, the AuNT networks demonstrate excellent thermal stability as an efficient Joule heater with a wide operating temperature range up to 390 °C. The in-plane buckled AuNT electrode exhibits controllable heat generation upon repetitive tensile strains of 60%, enabling wearable thermotherapy at highly strained joints. Such highly stretchable electrodes can be directly laminated on the balloon catheter as expandable, high-density nanomesh ablators, showing excellent thermal and moisture stability during 15 days of storage under conditions of relative humidity of 85% at 70 °C and over 1000 heating cycles to 60 °C, offering strong potential for biomedical therapeutics, such as thermal ablation and electrochemotherapy.