fig7

Figure 7. (A) Vibrational sum-frequency-generation spectra of water molecules at the water-graphene interfaces^[12]; (B) Schematic diagrams of interfacial water structures on CaF₂ substrate and on CaF₂-supported graphene with varying layer numbers^[12]; (C) Correlation between wettability implied by VSFG spectra and water-graphene adhesion energy based on WCA^[13]; (D) Thermal desorption spectroscopy curves of graphene grown on Cu (top panel) and bare Cu (bottom panel) at sub-monolayer coverages; Insets in the figures represent the corresponding macroscopically measured WCA^[120]. Figures are adapted from references^[12,13,120] with permission. VSFG: Vibrational and frequency generation; WCA: water contact angles.