Fabrication of Multifunctional Poly(acrylic acid) Hydrogels Using Nickel-Carboxymethyl Cellulose Nanocomposite Crosslinker

Abstract

Derivatives of cellulose, particularly carboxy methyl cellulose (CMC) is one of the popular physical crosslinkers used to improve the mechanical toughness and self-healing capability of polymeric hydrogels. In this study, along with CMC as the physical crosslinker, Ni-nanoparticle was used to synthesize polyacrylic acid (PAA)-Ni-CMC nanocomposites. The successful incorporation of Ni nanoparticles was confirmed using FTIR spectra as well as FESEM images. TGA and DTGA studies show that the thermal stability of CMC was significantly improved upon the incorporation of Ni-nanoparticles. The amount of Ni-nanoparticles was varied to study the effect on the mechanical toughness and self-healing capability of PAA-Ni-CMC nanocomposites. It was found that as the amount of Ni-nanoparticles increases, the tensile strength increases while the elongation of the hydrogel decreases. The Young's modulus and tensile strength of PAA-Ni-CMC hydrogel with 0.5% Ni-CMC crosslinker was found to be 0.19 MPa and 0.43 MPa, respectively. The nanocomposite hydrogel also showed considerable self-healing capability due to the ionic and coordination interaction of Ni with numerous physical interaction sites that CMC provides. The incorporation of the Ni-nanoparticle in the hydrogel network imparts the property of electrical conductivity; the PAA-Ni-CMC hydrogel showed the conductivity as high as 0.019 S/cm. Therefore, PAA-Ni-CMC composite hydrogel with excellent mechanical toughness, electrical conductivity, self-healing capability, and responsiveness to magnetic field possesses immense potential to be applied in biomedical applications.