conductive Polyvinylidene_fluoride HydroGel heterojunctions Fluoride Piezoelectric Electronics NUS Adhesion CuSubstrate LateralForceMicroscopy FM_SKPM light_emitting TemperatureControl Worcester_Polytechnic_Institute Sapphire single_layer HiVacuum cooling MeltingPoint InorganicCompound PVA Hexylthiophene IISCBangalore semifluorinated alkane plastic TappingMode Strontium HighAcpectRatio 3-hexylthiophene PyroelectricDetector Topography Conduct Vinylpyridine MoS2