Wetting Coefficient Calculator
Enter solid and liquid surface tensions plus solid-liquid interfacial tension to instantly calculate the wetting (spreading) coefficient.
Use the Wetting Coefficient Calculator
Surface Tension Inputs
All values in mN/m (= dyn/cm)
Or derive γSL from contact angle
Requires γSV and γLV to be filled in. Uses Young's equation.
Common presets
Result
Enter surface tension values and click Calculate.
Typical Surface Tension Values
| Liquid | γLV (mN/m) |
|---|---|
| Water (20 °C) | 72.8 |
| Ethanol | 22.4 |
| Glycerol | 63.4 |
| n-Hexane | 18.4 |
| Mercury | 486.0 |
| Acetone | 23.7 |
Summary
The wetting coefficient (also called the spreading coefficient) determines whether a liquid will spontaneously spread across a solid surface. It is calculated as S = γ_SV − γ_SL − γ_LV, where γ_SV is the solid-vapor surface tension, γ_SL is the solid-liquid interfacial tension, and γ_LV is the liquid-vapor surface tension. A positive spreading coefficient means the liquid wets the surface completely; a negative value means partial wetting or beading.
How it works
- Enter the solid-vapor surface tension (γ_SV) in mN/m.
- Enter the solid-liquid interfacial tension (γ_SL) in mN/m.
- Enter the liquid-vapor surface tension (γ_LV) in mN/m.
- The calculator applies S = γ_SV − γ_SL − γ_LV instantly.
- A positive S means complete wetting (spreading); negative S means partial wetting or no spreading.
- Use the contact angle field as an alternative — the tool converts it to γ_SL via Young's equation.
Use cases
- Determine whether a coating or adhesive will spread on a substrate.
- Evaluate ink wettability on paper or plastic films.
- Assess lubricant spreading on metal surfaces.
- Screen cleaning agents for their ability to wet and remove contaminants.
- Research surfactant formulations and surface treatments.
- Teach wettability concepts in physical chemistry courses.
- Compare water vs. organic solvent spreading on polymer films.
- Quality control of surface energy treatments like plasma or corona.