Correlation Between Swelling and Elasticity of Graphene Oxide-Polyacrylamide Composites

Abstract

Composites of Graphene Oxide (GO) and Polyacrylamide (PAAm) have been proposed as promising biomaterials for biomedicine and tissue engineering. The aim of this work is to investigate the relationship between swelling and mechanical properties of these composites and demonstrate the role of Graphene Oxide (GO) on the swelling and elasticity of the composites. Swelling experiments were performed in distilled water at 30 °C, monitoring the steady-state fluorescence intensity in real time, using Py in the GO-PAAm composites as a fluorescence probe. The diffusion coefficients, Dsc and the cooperative diffusion coefficients Dem were calculated using Fick's model and Li-Tanaka equations, respectively. The mechanical properties of the composites were investigated by the compression test before and after the swelling process. The GO content dependence of the shear modulus of the composites due to the volume phase transition was measured at 30 °C. After the swelling process, the shear modulus of GO-PAAm composites decreases with the increase of GO content above 8µl GO, indicating a critical value. An increase in GO content leads to a decrease in swelling capacity due to more cross-links and cross-link densities in the composites.