[paragoon]

I have a bunch of dilutions of an alcohol where the lowest concentration one has the highest surface free energy. The problem is, I don't really understand what a high surface free energy means. I know that surface free energy is also called surface tension which is easy to enough to understand. But what does this mean for the bulk solution below the surface and the distance between molecules? How does that compare to the surface?

I feel like high surface free energy means that there is a larger difference between the bulk solution and the surface but precisely what is different?

[paragoon]

For anyone who comes across this, I think I figured it out. Basically high surface free energy = high surface tension and low surface free energy = low surface tension. The surface tension depends on surface concentration. Every molecular compound has a certain surface concentration that has to be maintained on the surface of the solution. If the surface concentration is positive then that means the surface takes solute from the bulk solution to maintain its surface concentration. If the surface concentration is negative, then the surface pushes solute from the surface into the bulk to maintain that.
So with a positive surface concentration means that you have excess solutes on the surface. This means that the concentration is higher on the surface than in the bulk. Therefore, the average distance between molecules is higher in the bulk than on the surface (if surface concentration is positive).