The worst thing is a perfect flat surface, as you get a bond of static air to the surface. The flowing air has to pull away from this.
The best I have seen is when the wing surface has millions of small features which make the air turbulent - this is all on a macro scale at the surface.
The above flowing air rides over the turbulent air more freely.
Like a stack of steel plate on thousands of ball bearings. Imagine taking the bearings away and trying to slide the steel across the floor!
Sharks do this, their skin has details which stop the flowing water sticking.
Another way is the repel the air molecules at atomic level from the wing surface - reduces sticking. You use a high voltage electrode on leading edge to charge the air
So the wing and the air now share like charges and repel each other - less sticking.
Thx for the opportunity to share odd memories of random facts from decades ago.
I have ran out of skill now and will probably not bother you again,, Steve