Improving barrier performance of transparent polymeric film using silk nanofibril combine graphene oxide

Abstract

Abstract Silk nanofibril was developed from Bombyx mori cocoons by thermodynamically driven, salts, and annealing processes. Silk nanofibril/polyethylene terephthalate composite films were produced by casting different concentrations and amounts of silk nanofibril solutions on polyethylene terephthalate film. Then oxygen and water vapor transmission rates were determined. The results showed that oxygen transmission rate at optimum concentration of 0.30 wt% silk nanofibril/polyethylene terephthalate film was reduced by 33.4%, while the water vapor transmission rate was decreased by 37.6%. Graphene oxide at different wt% were also mixed with silk nanofibril solutions to develop silk nanofibril/grapheme oxide/polyethylene terephthalate films. The silk nanofibril/grapheme oxide/polyethylene terephthalate film developed from 0.15 wt% grapheme oxide decreased the oxygen transmission rate by 76.8% but did not significantly affect the water vapor transmission rate. The morphology of the top surface of silk nanofibril based barrier film was investigated by using scanning electron microscope that showed micellar unit or nanofibril aggregates formation. Fourier transform infrared spectroscopy and X-ray diffraction showed high β-sheet regions and crystallinity in 0.30 wt% silk nanofibril/polyethylene terephthalate film. Besides, the silk nanofibril/polyethylene terephthalate and silk nanofibril/grapheme oxide/polyethylene terephthalate showed smaller cavity size than polyethylene terephthalate that can reduce the oxygen and water vapor permeation. Transparent silk nanofibril/polyethylene terephthalate and silk nanofibril/grapheme oxide/polyethylene terephthalate films might be a great potential material in flexible electronics or food and pharmaceutical packaging.