Graphene oxide nanosheet-embedded crosslinked poly(ethylene oxide) hydrogel

Abstract

Nanofiller-reinforced polymer nanocomposites can be used to improve the mechanical, thermal, electrical, and barrier properties of neat polymers. In this study, two-dimensional graphene oxide (GO) nanosheets were successfully incorporated into hydrophilic crosslinked poly(ethylene oxide) (XPEG) hydrogels. Change in the gas permeability and mechanical strength were monitored as functions of the GO content and average GO flake size. The experimental results are discussed with two theoretical models (i.e., the modified Nielsen and Halpin-Tsai models) to predict the effect of two-dimensional GO nanofillers (e.g., loading content and alignment) on the gas permeability and mechanical properties of the GO-embedded XPEG hydrogels (GO–XPEGs). When the GO sheets were fully exfoliated and homogeneously dispersed in the XPEG matrix, their significant reduction in gas permeability and improvement in mechanical strength were in good agreement with those theoretical models. In particular, the incorporation of 4 wt % GO into the XPEG hydrogel matrix resulted in an 80–90% reduction in the gas permeability for various gases, including He, H2, O2, N2, CH4, and CO2. Also, with increasing GO content, both the Young's modulus and tensile strength of the GO–XPEG nanocomposite hydrogels increased significantly compared to those of the neat XPEG hydrogel.