Poly(ethylene oxide)/graphene oxide nanocomposites: structure, properties and shape memory behavior

Poly(ethylene oxide) (PEO)/graphene oxide (GO) nanocomposites with GO contents of 1, 3, 5 and 7 wt% were prepared by solution mixing followed by film casting. Field-emission scanning electron microscopy observations showed that the GO nanosheets are dispersed uniformly in the PEO matrix. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis of the nanocomposites revealed that there are hydrogen-bonded interactions between surface carboxylic acid on the GO sheets and ether group of the PEO. Differential scanning calorimetry (DSC), tensile testing, and dynamic mechanical analysis (DMA) showed that, with increasing GO content in the nanocomposites, the melting temperature and degree of crystallinity decreased while glass transition temperature, tensile modulus, strength and elongation-at-break concurrently increased. DMA results also demonstrated the presence of a rubbery plateau above the melting temperature of the PEO/GO nanocomposites, and the moduli at the plateau region increased with increasing GO content in the nanocomposites, implying that the PEO/GO nanocomposites formed a physically crosslinked structure. PEO/GO nanocomposites with GO contents higher than 5 wt% exhibited excellent thermally and infrared-triggered shape memory behavior.