Adhesion force of a wedge

The macroscopic theory of capillarity is usually applied to evaluate the adhesion forces produced by fluid bridges between solid particles. A refined mesoscopic description incorporates the disjoining pressure, which results from the long range forces between the fluid and the solid substrates. In the case of simple nonpolar fluids the influence of the disjoining pressure on adhesion is expected to be negligibly small. Water bridges, however, sometimes have very large disjoining pressures on various substrates. Then mesoscopic theory leads to pull-off forces which differ from the predictions of the macroscopic approach.