Enhancing Mechanical and Sensing Performance of Conductive Hydrogel via Ga-Droplet Costabilization with Polyaniline and Xanthan Gum

Abstract

Conductive hydrogels incorporating liquid metals, particularly gallium (Ga) droplets, have garnered significant attention owing to the multifaceted functionalities they offer. In this study, we introduce a liquid-metal-based conductive hydrogel synthesized through radical polymerization of acrylic acid (AA) in the presence of Ga droplets stabilized by polyaniline (PANI) nanofibers and xanthan gum (XG) at room temperature. The incorporation of PANI not only enhances the stability of Ga-droplet dispersion but also improves the hydrogel’s mechanical properties, including tensile strength, toughness, and sensitivity as a sensor material. With the addition of 0.5 wt % PANI, the hydrogel displays an elongation at break of 964% and a tensile strength of 265 kPa, while exhibiting a sensor gauge factor (GF) of 13.4 within a strain range of 400–600%. The reversible noncovalent cross-links within the hydrogel confer excellent self-healing properties, achieving 98% self-healing efficiency in elongation at break within 6 h and 90% conductivity self-healing within 83 ms. Additionally, the hydrogel’s abundant functional groups enable strong adhesion to various substrates. As a sensing material, the hydrogel demonstrates rapid response and recovery times (250/250 ms), low detection limits (0.1%), and good durability (500 cycles under 10 and 100% strains). The cross-linked network composed of XG, PANI, and PAA imparts the hydrogel with water retention. Moreover, glycerol treatment reinforces the hydrogel’s mechanical strength and sensing abilities, extending their effectiveness even under extreme temperature conditions. As a result, the XG-PANI-Ga-PAA hydrogel-based strain sensor has emerged as a promising tool for monitoring human health and detecting a wide range of human activities with reliability and precision.

Topics & Concepts