Rational design of sulfonated poly(ether ether ketone) grafted graphene oxide-based composites for proton exchange membranes with enhanced performance

• Published in: Polymer (Guilford) 2018-05, Vol.144, p.7-17
• Main Authors: Feng, Mengna, Huang, Yumin, Cheng, Yue, Liu, Jingchun, Liu, Xiaobo
• Format: Article
• Language: English
• Subjects: Chemical synthesis; Composite materials; Conductivity; Esterification; Graphene; Graphene oxide; Graphite; High temperature; Interfacial bonding; Interfacial compatibility; Ketones; Membranes; Metal oxides; Polymers; Proton exchange membrane; Protons; Structural similarity; Sulfonated polyarylene ether nitrile; Swelling ratio; Water uptake
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2018.04.037

Sulfonated graphene oxide (SGO) was synthesized by direct esterification reaction between graphene oxide (GO) and hydroxylated sulfonated poly(ether ether ketone) (SPEEK-OH) and then incorporated into sulfonated polyarylene ether nitrile (SPEN) to explore the effect of varying loading on performances of proton exchange membranes. It was found that SGO are uniformly dispersed and form perpendicular packing structure in matrix, triggering the formation of continuous and long-range proton transfer channels and effectively improving proton conductivity. Meanwhile, the water uptake, swelling ratio and methanol permeation are lowered to the corresponding composite PEM compared to pristine SPEN membrane. All of these are attributed to the formation of strong interfacial interaction between SPEN and SGO. As a result, the composite membranes possesses higher selectivity than pristine SPEN. Specially, the composite membrane contained 2 wt% SGO show the lowest swelling ratio at high temperature (just 13.77% at 80 °C) and the highest proton conductivity of 0.183 S·cm−1 at 80 °C. Our investigation indicates the great potential of SGO in fabricating composite PEMs and also provides a new approach for the development of PEMs. [Display omitted] •The hydroxylated sulfonated PEEK grafted GO was designed and synthesized.•Structural similarity between SGO and SPEN ensured the interfacial compatibility.•The prepared composite membranes showed unprecedented dimensional stability.•The continuous proton transport networks were formed at the SPEN/SGO interface.•The possible proton conducting process of composite membrane was proposed.