High-Strength Antifreezing Gelatin/PVA/PEDOT Composite Conductive Hydrogel for Flexible Strain Sensors and Triboelectric Nanogenerators

Conductive hydrogels exhibit remarkable flexibility and tunable conductivity, rendering them highly promising for applications in flexible strain sensors and triboelectric nanogenerators (TENGs). However, conventional conductive hydrogels suffer from certain limitations, such as insufficient mechanical strength and inadequate frost resistance. In this study, an in situ polymerization method was employed to construct a poly(3,4-ethylenedioxythiophene) (PEDOT) conductive network within a poly(vinyl alcohol) (PVA) solution. Subsequently, gelatin was incorporated to establish an interpenetrating dual physical cross-linked hydrogel network with PVA. Finally, via a straightforward solvent displacement process, a mixture of ammonium sulfate and zwitterionic betaine was integrated into the hydrogel network. The resultant hydrogel (GPPB) demonstrates exceptional mechanical and electrical properties (the tensile strength reaches 2.2 MPa and the electrical conductivity is 2.2 S/m) and robust frost resistance (down to −40 °C). Moreover, the flexible strain sensor based on the GPPB hydrogel exhibits a broad detection range (up to 500%), high sensitivity (GF = 3.51), and is capable of monitoring movements across various human body parts. Additionally, the TENG assembled using the GPPB hydrogel delivers stable power output, enabling it to drive small wearable electronic devices and facilitating self-powered strain sensing.