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Nafion, a perfluorosulfonic acid polymer, has been the standard membrane material for direct methanol fuel cells (DMFCs) due to its proton-carrying capabilities, despite its shortcomings as a methanol barrier. To attain self-healing and methanol-blocking properties, the incorporation of poly(vinyl alcohol) (PVA) polymer into Nafion was pursued. However, this strategy resulted in low proton conductivity. Thus, acid functional groups were added to a secondary modifier to boost proton conductivity. In this work, sulfonated graphene oxide (SGO) was assembled with Nafion and PVA through a simple freezing-thawing method to demonstrate a self-healable proton exchange membrane (PEM) without compromising the proton conductivity of Nafion. The synergistic effect of SGO in methanol-blocking and proton transport successfully strode over recast Nafion by hampering 33.2 % of methanol permeation and increasing 19.5 % of proton conductivity. As a result, the selectivity of the best hybrid PEM (N/PVA/SGO1.0) was increased by 1.8 times in comparison to recast Nafion. A single cell passive DMFC made using the novel hybrid membrane exhibited a power density of 6.07 mW cm−2at a current density of 26.48 mA cm−2, and an open circuit voltage of 0.55 V at room temperature using 4 M methanol. This performance was essentially higher than that achieved by recast Nafion and commercial Nafion 117. The N/PVA/SGO1.0 hybrid membrane also showed remarkable self-healing properties, with 89 % recovery of methanol blocking function through reversible hydrogen bonding, illustrating its tremendous sustainable potential for use in DMFCs.

The oxygen air production are generally be achieved by pressure swing adsorption (PSA) and cryogenic distillation. Both of the techniques are able to produce high purity oxygen level which is more than 95% with a production volume of 20 – 300 tons per day. These techniques however required high energy consumption and with the rising cost of energy, membrane separation is a good option as it require relatively low energy requirement. Membrane separation technique is an emerging technique which garners the interest from academia and industry from last decade as an alternative method to produce oxygen enriched air. To date, the commercially available and research institution self-fabricated polymeric membrane are unable to produce an economically viable membrane with high permeability and selectivity in a large scale production relative to the conventional method. In this works, the progress of the application of polymeric in O2/N2 separation which including the recent developed of self fabricated polymeric membrane and the aspect of operation parameter is discussed. Finally, the paper also intends to present a brief overview of the development of membrane separation technique in O2/N2 separation in addressing the strategies and improvement in the fulfillment of industrial application interest.