Preparation and characterisation of poly(ethylene glycol)‐adsorbed graphene oxide nanosheets

Abstract

AbstractPolymer–graphene nanocomposites are attracting growing attention of scientists and engineers as graphene‐based nanofillers may enhance the properties of polymers significantly. This study aims to understand the adsorption behaviour of polymers on graphene oxide (GO) nanosheets. GO is synthesised using Hummerʼs method by oxidising graphite. Poly(ethylene glycol)s (PEGs) with different molecular weights are used as polymer models. A series of PEG/GO nanohybrids is prepared by applying different parameters in the solution processing method. Fourier transform infrared spectroscopy, X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, polarised optical microscopy, scanning electron microscopy and atomic force microscopy are used for characterising the hybrid nanomaterials. The characterisation results confirm the successful preparation of GO and the adsorption of the PEGs onto GO. The maximum amount of adsorbed PEG was 38 wt%. The adsorption amount of PEG increases by 46% after reducing the mixing time from 192 h to 72 h, 1700% due to an increase in the molecular weight from 1k to 100k, 13% for doubling the mixing ratio of PEG:GO from 1.5:1 to 3:1, 44% for applying no further washing procedure and 73% for applying all these parameters concurrently. The adsorption onto GO reduces the crystallinity of PEGs due to chain confinement. Different surface morphologies are observed in the hybrid nanomaterials showing various thicknesses of the PEG layer adsorbed on the GO nanosheets. This study may offer new insights into the manipulation of the interface in polymer–GO nanocomposites. © 2020 Society of Industrial Chemistry