Study of gas transport properties of multi-walled carbon nanotubes/polystyrene composite membranes

The multi-walled carbon nanotube (MWCNT) dispersed polystyrene (PS) composite membranes have been prepared by solution cast method for hydrogen gas permeation application. The structural and morphological properties of these prepared composite membranes have been characterized by X-Ray diffraction (XRD), Atomic force microscopy (AFM) and Scanning electron microscopy (SEM). The optical absorbance measurement of the composite membranes has been carried out by UV–Vis Spectroscopy. The effect of electric field alignment of MWCNT in PS matrix on gas permeation has also been characterized for hydrogen gas with different gas mixtures. The permeability measurements indicated that the electrically aligned MWCNT in PS has shown higher permeability for hydrogen gas as compare to randomly dispersed MWCNT in PS. The enhancement in permeability is explained on the basis of easy channels provided by electrically aligned MWCNT in PS matrix. The effect of thickness of membrane on the gas permeability has also been studied and thickness of about 60 μm was found to be optimum thickness for fast hydrogen gas permeations. The selectivity measurements show that MWCNT aligned PS composite membrane are highly selective for hydrogen gas in presence of different gas mixtures therefore these composite membrane can be used for hydrogen purification in fuel cell technology.