Organic solvent supported fabrication of transparent free standing graphene oxide membranes

Abstract Free standing graphene oxide membranes (FSGOMs) were prepared by evaporation of GO-methanol/GO-water-methanol dispersions on silicon substrate and, subsequent delamination using 2-propanol or by mechanical exfoliation. SEM and XRD studies indicated the influence of methanol-water composition on morphological features and interlayer spacings of FSGOMs. Methanol provides superior surface coverage and fast drying conditions as compared to water-methanol and, surface morphology of FSGOMs can be tuned by providing sufficient duration for the settlement and stacking of GO sheets. Delamination of membranes is largely determined by dispersion composition, hydrophilicity of substrate and thickness of membrane. FSGOMs prepared in this work displayed considerable transmittance in visible region, mechanical flexibility and thermal stability of chemical composition up to 250 °C. These membranes are remarkably stable in 2-propanol, attributed to unimpeded permeation of propanol molecules through intra-layer spacings and introduction of fresh interactions. FSGOMs showed ~63% of methylene blue (MB) removal efficiency from MB-propanol solutions through multiple filtration cycles and the filtration ability may be ascribed to intra-layer entrapment of MB molecules through chemisorption at functional groups of GO. Present work provides quick, facile and economical method for damage-free FSGOM preparation, which has potential applications in the development of membranes for organic solvent filtration.