pH-responsive polymer hydrogel nanocomposites for sensor applications: A review

Abstract

pH-sensitive polymer hydrogel nanocomposites have been a promising class of material for sensor technologies due to their excellent sensitivity, tunability, and flexibility. Very useful for monitoring environmental and biological pH variations, pH-sensitive smart hydrogels contain ionizable functional groups whose structural and physicochemical properties alter in response to alterations in pH. The incorporation of nanomaterials like graphene, metal nanoparticles, carbon nanotubes, and silica enhances their mechanical properties, conductivity, and stability, thus widening their potential applications. Advances in fabrication methods such as in-situ polymerization, chemical crosslinking, and layer-by-layer assembly have assisted in the synthesis of highly effective and durable sensor materials. These sensor devices based on nanocomposite materials are broadly used in biomedical applications such as wound sensing, drug delivery systems, and wearable health diagnostic applications, and also in environmental applications to determine water quality and soil condition. Despite its advantages, there still exist challenges such as response time, biocompatibility, and mass production. Future research should aim at improving material compositions, increasing biodegradability, and introducing multifunctional features into future-generation smart sensing technologies. Highlighting its ability to revolutionize numerous disciplines, this article presents an extensive review of the structure, composition, manufacturing, and useful applications of pH-responsive polymer hydrogel nanocomposites in sensor technology.