The effect of dodecylbenzenesulfonic acid molecules on poly(4,4-diphenylether-5,5-dibenzimidazole) films

Abstract

The main aim of the present work was to approach the effect of the addition of an organic acid dopant, dodecylbenzenesulfonic acid (DBSA), in the preparation of poly(4,4-diphenylether-5,5-dibenzimidazole) (OPBI) films, commonly used as proton exchange membranes (PEMs). For this purpose, DBSA was blended with OPBI polymer matrix, at different concentrations, to evaluate the effect of such molecules in the proton conductivity of OPBI membranes. A substantial improvement in the dimensional stability of OPBI film, either for the undoped or for the phosphoric acid doped membranes, with low content of DBSA (12.5 wt.%) was achieved. Moreover, the charge mobility in OPBI/DBSA films remained stable between 22 oC and 140 oC, for both doped and undoped states. Therefore, the utilization of OPBI/DBSA system can be envisaged for proton exchange membrane operations at moderate temperature interval.