An Aquivion (R) E87-12 S short-side-chain perfluorosulfonic acid (SSC-PFSA) membrane with equivalent weight (EW) of 870 g/eq and 120 mu m thickness produced by Solvay Specialty Polymers was tested in a polymer electrolyte membrane water electrolyzer (PEMWE). For comparison, a benchmark Nafion N115 membrane (EW 1100 g/eq) of similar thickness was investigated under similar operating conditions. Both membranes were tested in conjunction with in-house prepared unsupported IrO2 anode and carbon-supported Pt cathode electrocatalysts. The electrocatalysts consisted of nanosized IrO2 and Pt particles (particle size similar to 2-4 nm). Electrochemical tests showed better water splitting performance for the Aquivion (R) membrane and ionomer based membrane-electrode assembly (MEA) as compared to Nafion (R). Lower ohmic drop constraints and smaller polarization resistance were observed for the electrocatalyst-Aquivion (R) ionomer interface indicating a better catalyst-electrolyte interface. A current density of 3.2 A cm(-2) for water electrolysis was recorded at 1.8 V cell voltage and 90 C with the Aquivion (R) based MEA. Some performance decay with time was observed indicating that the system requires further optimization of the interface characteristics. (C) 2014 Elsevier B.V. All rights reserved.