Contact Angle & Wetting Physics

Explore how surface energy, liquid surface tension, and the Young-Dupré equation determine droplet shape.

Droplet Cross-Section

Young's Equation Parameters

cos θ_Y = (γ_SG − γ_SL) / γ_LG
Wenzel: cos θ_W = r · cos θ_Y
Young θ_Y =
Wenzel θ_W =
Spreading coef. S =
Work of adhesion W_a =
Class:
Young's equation balances three interfacial tensions at the three-phase contact line. Roughness amplifies hydrophobic/hydrophilic character (Wenzel). Real lotus leaves: θ>150° (superhydrophobic via micro/nano-texture).

Contact Angle History & Wetting Diagram

Left: contact angle vs γ_SG/γ_LG ratio. Right: regime map. Current ★