Wettability of graphene, water contact angle, and interfacial water structure

Understanding the details of water interacting with graphene is essential for various applications, such as desalination, energy storage, and catalysis. However, hydrogen-bonding structure at graphene-water interface has not been fully understood. Vibrational sum frequency generation (VSFG) spectroscopy suited to elucidate interfaces. With varying numbers layers or tuning doping level a single monolayer, interfacial differs substantially. Specifically, number increases, molecules non-H-bonded, dangling OH groups become increasingly apparent. The fraction inferred from VSFG spectrum correlates adhesion graphene. This observation suggests that could be an incisive technique measuring on any spatially confined where contact angle cannot measured. We anticipate will shed light wettability low-dimensional materials.