Sulfonated poly(arylene ether nitrile)-based hybrid membranes containing amine-functionalized GO for constructing long-range ionic nanochannels

Abstract

To simultaneously balance proton conduction and methanol diffusion, the acid-base hybrid membranes based on sulfonated poly(arylene ether nitrile) (SPEN) with 3-aminopropyltriethoxysilane functionalized graphene oxide (NGO) are prepared by solution-casting method. The loading of NGO is varied to explore the influence on cross-sectional morphology, dimensional stability, proton conductivity and methanol permeability of composite membranes. In this way, the interfacial ionic nanochannels are established at the interface of NGO and SPEN, constructing the long-range ionic nanochannels to provide fast proton transfer. Meanwhile, the formation of more zigzag transportation channels could effectively prevent methanol diffusion. The improved properties of the composite membranes can be attributed to the excellent interfacial interactions induced by acid-base and hydrogen bonding interactions. The composite membrane with 1 wt% NGO shows high proton conductivity (0.104 S·cm−1 at 20 °C) and low methanol permeability (1.74 × 10−7 cm2·s−1 at 20 °C), exhibiting higher selectivity (5.977 × 105 S cm−3s) compared with pure SPEN and Nafion 117 membranes. Therefore, it will provide a feasible pathway to conquer the trade-off effect between proton conductivity and methanol resistance for direct methanol fuel cells (DMFC) applications.