observations of wetting. These observations confirm that the modified Young’s equation does not hold at the micro-nano scales. In addition the sign of the line tension is not maintained through the modified Young’s Equation. For a sessile droplet [Contact angle], the free energy of the three phase system can be expressed as: At constant volume in thermodynamic equilibrium, this reduces to: Usually, the VdP term has been neglected for large droplets, however, VdP work becomes significant at small scales. The variation in pressure at constant volume at the free liquid-vapor boundary is due to the Laplace pressure [Laplace pressure], which is proportional to the mean curvature of the droplet, and is non zero. Solving the above equation for both convex and concave surfaces yields: Where the constant parameters A, B, and C are defined as: , and This equation relates the contact angle , a geometric property of a sessile droplet to the bulk thermodynamics, the energy at the three phase contact boundary, and the curvature of the surface α. For the special case of a sessile droplet on a flat surface (α=0), The first two terms are the modified Young’s equation, while the third term is due to the Laplace pressure. This nonlinear equation correctly predicts the sign and magnitude of κ, the flattening of the contact angle at very small scales, and contact angle hysteresis. Computational prediction of wetting For many surface/adsorbate configurations, surface energy data and experimental observations are unavailable. As wetting interactions are of great importance in various applications, it is often desired to predict and compare the wetting behavior of various material surfaces with particular crystallographic orientations, with relation to water or other adsorbates. This can be done from an atomistic perspective with tools including molecular dynamics and density functional theory. In the theoretical prediction of wetting by ab initio approaches such as DFT, ice is commonly substituted for water. This is because DFT calculations are generally conducted assuming conditions of zero thermal movement of atoms, essentially meaning the simulation is conducted at absolute zero. This simplification nevertheless yields results that are relevant for the adsorption of water under realistic conditions and the use of ice for the theoretical simulation of wetting is commonplace. Non-ideal rough solid surfaces Unlike ideal surfaces, real surfaces do not have perfect smoothness, rigidity, or chemical homogeneity. Such deviations from ideality result in phenomenon called contact angle hysteresis, which is