We can learn the following properties of water (or any liquid in general) in the nano scale and its application.
(i) Mechanical properties of water column in the nano scale such as surface tension, hydrogen bonding structure, bonding strength, and viscosity.
(ii) Thermodynamics of water under strong negative pressure such as liquid-vapor interfacial instability or liquid-vapor phase transition (homogeneous nucleation).
(iii) Electrical or optical properties of thin water such as the conductivity or polarizability in the nano scale.
(iv) Phase transition: Ice formation (freezing transition) of water in ambient conditions when an electric field is applied between tip and substrate.