semifluorinated_alkane NtuEee heterojunctions FailureAnalysis Piezoresponse PinpointPFM nanomechanical ContactModeDots pinpoint mode HOPG block_copolymer phase_change Lateral_Force_Microscopy contact suspended_graphene temperature_control MagneticPhase biocompatible IVSpectroscopy NTU Polytetrafluoroethylene Pvdf Granada Polyethylene PFM PolyvinylideneFluoride PolymerPatterns Optic atomic_steps Solar Modulus Titanate LowDensityPolyethylene GaN single_layer