AEAPDES Calcium Graphite ForceMapping Polypropylene BiFeO3 Current CrAu Polymer Electrode StyreneBeads Subhajjit CopperFoil fluorocarbon Ucl KevlarFiber NusEce ElectrostaticForceMicroscopy Mechinical atomic_layer tip_bias_mode Microchannel HDD self-assembly InorganicCompound VerticalPFM MfmPhase Fluoride BCZT Tungsten_disulfide Mapping temp NUS_Physics suspended_graphene 2-vinylpyridine