Floppy SrO kelvin probe force microscopy Copolymer Step PolyvinylideneFluoride PinpointPFM PhaseImaging LateralForce Sidewall Molybdenum_disulfide MultiferroicMaterials ConductingPolymer AAO Lateral_Force_Microscopy Tape chemical_compound Inorganic AlkaneFilm Display Conducting ito_film Anneal Chromium exfoliate PVAC frequency_modulation KAIST Phosphide DNAProtein SrTiO3 NusEce Fluoride 2dMaterials CntFilm