Sapphire Polyethylene Wonseok Scratch China Electical&Electronics Fluoride Optoelectonics BariumTitanate Composite Roughness CuFoil HanyangUniv AmplitudeModulation Cobalt-dopedIronOxide Metal-organicComplex TemperatureControllerAFM PvdfBead Memory NeodymiumMagnets HOPG PANI self_healing Stiffness HydroGel Plug AM_KPFM AM_SKPM Morphology SingleLayer SingleCrystal StyreneBeads ScratchMode fe_nd_b Array