Rapid and scalable fabrication of ultra‐stretchable, anti‐freezing conductive gels by cononsolvency effect

Abstract

Abstract With the emergence of soft electronic devices, the requirements for conductive soft materials are unprecedentedly high. Among various soft materials, hydrogels are gaining tremendous attention for their superior softness, wetness, responsiveness, and biocompatibility. However, hydrogels inevitably lose elasticity and ionic conductivity at subzero temperature because of water freezing in the polymer matrices, severely limiting applications at low temperatures. Herein, we propose a rapid fabrication strategy to produce anti‐freezing conductive gels with poly(vinyl alcohol) on a large scale within minutes (vs hours/days in conventional methods) using a water/DMSO binary liquid system, which serves as gelation inducer via cononsolvency and anti‐freezing solvents simultaneously. The gel with 60 wt% DMSO shows the best anti‐freezing performance, remaining unfrozen at temperatures lower than −50°C, while also maintaining the highest mechanical properties with a tensile strength of 1.1 MPa, toughness of 10.9 MJ/m3, and elongation of 1500% outperforming the most previous reports. After incorporating H2SO4, the gels exhibit a high ionic conductivity of 5.25 S/m and maintain 1.65 S/m even at −50°C. Furthermore, an all‐in‐one supercapacitor is fabricated to demonstrate the potential of the anti‐freezing gel in soft device applications with good performance at subzero temperatures. A full recyclability of the material was also demonstrated.

Keywords

• anti‐freezing
• conductive
• cononsolvency
• rapid
• ultra‐stretchable