MembraneFilter TiO2 PinpointPFM non_contact PhaseImaging ring shape Melt SingleLayer InsulatorFilm SPMLabs food PinpointNanomechanicalMode 2d_materials Liquid CVD Silicon Fendb Tin sulfide Microchannel Al2O3 SiliconCrystal EPFL DeflectionOptics Reduction Morphology ForceVolumeImage Friction Adhesion MolybdenumDisulfide Step Memory InLiquid Mobile molecules flakes