The structure and molecular processes occurring at the Nafion (R) membrane/electrode interface remain poorly understood. The present study aims at elucidating the nano-scale properties of the Pt(100)/Nafion (R) interface using scanning probe techniques, namely STM and AFM. In STM, the surface morphology of the thin Nafion (R) film appears smooth on the atomic scale; monoatomic steps of the substrate are well visible. The thickness of the Nafion (R) membrane is determined using AFM tip penetration experiments and also by scratching of the Nafion (R) layer from the electrode surface. Force deflection ("approach") curves demonstrate that the tip penetrates the Nafion (R) layer at a normal force greater than 5 nN. (C) 2014 Elsevier Ltd. All rights reserved.