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Conductive hydrogels are promising flexible conductors for human motion monitoring. However, this kind of wearable strain sensor has often shown weak mechanical properties. To overcome the inherent mechanical weakness and improve the electrical conductivity, CNT-Br/PEDOT:PSS/PAAS triple-network penetrating conductive hydrogels (CBP) are fabricated. The n-butylimidazolium bromide salt-functionalized MWCNTs (CNT-Br) as conductive fillers form a three-dimensional conductive path through the crosslinking agent XR-100, penetrating with the skeleton of crosslinking sodium polyacrylate. The conductive liquid PEDOT:PSS is further evenly dispersed in the penetrating double network to further enhance the electrical conductivity of the hydrogels. CNT-Br without obvious agglomeration significantly improved the thermal stability and mechanical properties of CBP. Moreover, CNT-Br enabled the PEDOT:PSS components to be more evenly dispersed in the PAAS matrix. Due to the good conductive paths inside the hydrogels, the maximum electrical conductivity (CBP10) increases to 10.35 mS cm−1, which is 415% higher than that of pure P1. Our work provides a method to prepare conductive hydrogels with high electrical conductivity and excellent mechanical properties, which can be used for human joint motion detection. [ABSTRACT FROM AUTHOR]

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 (Na 3 Cit), 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. [Display omitted] • Double network conductive hydrogels (PHTF@DNH) were prepared under double autocatalytic conditions. • The hydrogel showed exceptional electrical conductivityand sensitivity. • The hydrogel exhibited excellent mechanical and swelling properties. • At a very low temperature (−30 °C), the hydrogel could maintain stable. [ABSTRACT FROM AUTHOR]