Does surface tension change with concentration?
At constant temperature and pressure,
n=no. of moles of the surfactant
by comparing the two equations (1) & (2) for dG, we get
Now for an interface in which oil and water for example, are separated by a geometrically flat surface.The approximation implies that on the surfactant S accumulates at the surface and hence that
The equation becomes
for dilute solutions,
therefore at constant temperature,
I've tried to make the derivation look as simple as possible.If still not understood , leave a comment below.