Worcester_Polytechnic_Institute PS_PVAC SAM Hydroxyapatite Thermoplastic_polyurethane SKKU neodymium_magnets Gong semifluorinated alkane PtfeMembrane HfO2 piezoelectric force microscopy Nanotechnology Composite PatternedSapphireSubstrat ScanningIon-ConductanceMicroscopy Tapping DIWafer ForceVolumeMapping Corrosion Indent GalliumPhosphide LiquidCell TungstenThinFilmDeposition membrane Pinpoint PFM Temasek_Lab C_AFM ChemicalCompound Liquid LateralForceMicroscopy doped HardDiskMedia graphene_hybrid SurfaceChange