A rapid polymerization of flexible wearable hydrogels sensors with excellent mechanical property, conductivity and frost resistance performance based on double autocatalytic system

Abstract

Recently, wearable services that are flexible and based on conductive hydrogels have rapidly evolved and found numerous applications. These conductive hydrogels must possess remarkable mechanical strength, electrical conductivity, and sensing stability, while also being able to withstand low temperatures. However, creating hydrogels that meet all these requirements can be a lengthy and complicated process. Herein, we quickly (10 s) generated a double network conductive hydrogels (PHTF@DNH) using the double autocatalytic system consisting of TA (Tannic acid) and Fe3+. Due to the hydrogen bonding interactions between polyacrylamide (PAM), chitosan quaternary ammonium salt (HACC), TA, cross-linking of N, N′-methylene-bis-acrylamide (MBA), and ionic conduction of sodium citrate (Na3Cit), the hydrogel exhibit excellent tensile property (stress of 177.40 kPa, elongation at break of 788%), compressive performance (compressive strength of 1.1 MPa at 80% deformation), desirable toughness (702.60 kJ/m3), and exceptional cyclic compression and swelling properties. The hydrogel-based sensors show exceptional electrical conductivity (59.02 mS/cm), sensitivity (GF value of 1.13 at 100–550% strain), broad detection range and good signal stability. Even at −30 °C, the hydrogels still maintained stable. Eventually, it is harmless to human skin. We believe that the PHTF@DNH offer a new approach to the manufacture of sensitive wearable electronic devices.