Fig. 2From: In Situ Probing the Relaxation Properties of Ultrathin Polystyrene Films by Using Electric Force MicroscopyAFM topography images and surface potential of ultrathin PS films obtained in a single measurement. a The scratched film for thickness measurement. b AFM morphology of charged ultrathin PS film. c Surface potential images of charged ultrathin PS film with positive charge and d negative chargeBack to article page