Pinpoint PFM ThermalConductivity plastics SingleLayer piezoelectric force microscopy PinpointPFM NUS Aluminium_Oxide Conducting Gallium AM_SKPM flakes Pores TemperatureControllerStage CalciumHydroxyapatite MolybdenumDisulfide Magnetic NUSNNI FM_SKPM Polyaniline Adhesive 2dMaterials LithiumNiobate PFM CBD PUR FrequencyModulation PolymerPatterns FrictionalForceMicroscopy ElectroChemical Composition HexacontaneFilm atomic_layer Morphology Biofilm