If the surface is wetted homogeneously, the droplet is in Wenzel state. In Wenzel state, adding surface roughness will enhance the wettability caused by the chemistry of the surface. The Wenzel correlation can be written as cos ⁡ ⁡ θ θ m = r cos ⁡ ⁡ θ θ Y where θ m is the measured contact angle, θ Y is the Young contact angle and r is the roughness ratio. The roughness ratio is defined as the ratio between the actual and projected solid surface area.