Gibbs Adsorption Isotherm (Surface Excess) (Γ = -(c/RT)(dγ/dc))
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Γ = -(c/RT)(dγ/dc)
What each symbol means
| Symbol | What it stands for |
|---|---|
| R | Gas constant |
| T | Absolute temperature |
| c | Bulk concentration of solute |
| Γ | Surface excess concentration (mol m⁻²) — adsorption at interface |
| γ | Surface tension of solution |
When to use this
Dilute solution; ideal behaviour approximations; relates surface tension gradient to adsorption. If dγ/dc < 0 (γ falls as solute increases), Γ > 0 — positive adsorption (surfactants).