cannabis NiFe Polytetrafluoroethylene Vinylpyridine frequency_modulation lift_mode LifeScience KevlarFiber Foil mechanical_property Fe_film Wonseok sputter LateralPFM Terrace HafniumDioxide ito_film Cross-section nanomechanical fluoroaalkane INSPParis OrganicSemiconductor ScanningTunnelingMicroscopy Thermal Zhi semifluorinated_alkanes #Materials MoS2 DomainSwitching suspended_graphene Mechinical blended polymers Conductivity Plug Pinpoint PFM