Enhancing Conductivity of Polyacrylamide Hydrogel With Surface‐Coated Hydroxylated Carbon Nanotubes for Wearable Device Applications

Abstract

In this study, we successfully prepared a composite hydrogel that integrates the superior conductivity of carbon nanotubes (CNTs) with the elasticity of hydrogels. This was achieved by depositing a layer of hydroxylated CNTs onto a polyacrylamide (PAM) hydrogel. The PAM hydrogel was immersed in a CNT dispersion at 50°C and subjected to ultrasonic treatment for 30 min, followed by a 50% dehydration process to achieve densification. This process enabled the adsorption of CNTs onto the PAM hydrogel surface, forming robust physical entanglements and hydrogen bonds with the PAM polymer chains. Consequently, this significantly strengthened the interfacial adhesion between the CNTs and the hydrogel, yielding a more durable and resilient composite material. Impressively, the adhesion strength between the CNT layer and the PAM‐CNT composite hydrogel surface reached a remarkable 61.75 J/m2, contributing to its good electrical conductivity (1.284 ± 0.034 S/m), stability, and mechanical properties. Additionally, our study explores the application of the composite material in wearable devices by quantifying its response to pressure, bending, and stretching through resistance change measurements. The findings indicate that this research introduces a new method for preparing conductive hydrogels and offers valuable insights for their use in electronics, biomedicine, and various other related domains.