In recent years, a lot of attentions have been paid for a development of water-free polymer electrolyte membranes fuel cells (PEMFC) at intermediate temperatures (above 100 degreesC) because of many technological advantages of higher temperature operation. However, the proton conductivity of conventional polymer membranes under water-free condition is usually very low and the polymeric membranes are not stable at higher temperatures. So, the development of non-hydrous proton conducting membrane under water-free condition has been a state of the art issue in the advanced PEMFC technology. In this study, non-hydrous protonic conducting material was prepared by the mixing of acidic surfactant of mono-dodecylphosphate (MDP) and organic base of benzimidazole (BnIm). The proton conductivity and thermal stability of MDP-BnIm mixed material increased with the mixing ratio of BnIm. Maximum proton conductivity of MDP-BnIm mixed material (BnIm mixing ratio of 200 wt.%. vs. MDP) was found to be 1 x 10(-3) S cm(-1) at 150 degreesC under water-free condition. (C) 2003 Elsevier Science Ltd. All rights reserved.