Highly Dispersed Graphene Network Achieved by using a Nanoparticle‐Crosslinked Polymer to Create a Sensitive Conductive Sensor

Abstract

AbstractElectrically conductive hydrogels (ECHs) have attracted significant interest in the past, owing to their potential applications in flexible electronic devices. The incorporation of reduced graphene sheets (GSs) is one effective way to endow hydrogels with electrical conductivity. However, inhomogeneous distribution of GSs in a hydrogel matrix has a side effect on the conductivity for GS‐based ECHs. In this work, cement‐released calcium hydroxide nanospherulites (CNSs) are innovatively employed to help disperse GSs in a poly‐acrylamide (PAM) hydrogel matrix. An excellent ECH with good mechanical performance is achieved by dispersing GSs homogeneously into the PAM hydrogel matrix with the support of CNSs. Raman measurements confirm the vital role of CNSs in dispersing GSs homogeneously into the hydrogel matrix. With a very low GS content of 0.2 wt %, the electrical conductivity of such ECH sample can reach four times than that of reported GS‐based conductive hydrogels dispersed by conventional surfactants. Furthermore, the homogeneous distribution of GSs in the hydrogel matrix also promotes energy dissipation in the mechanical property, leading to a high compression stress (214 MPa) and stretching stress (325 KPa) for such ECHs. Owing to its rapid response speed and high stability, this ECH is used as a strain sensor to monitor deformation. In a broader context, this ECH material may have potential applications in smart sensors and wearable devices.