The effect of surface roughness on the adhesion of elastic solids

We study the influence of surface roughness on the adhesion of elastic soli ds. Most real surfaces have roughness on many different length scales, and this fact is taken into account in our analysis. We consider in detail the case when the surface roughness can be described as a self-affine fractal, and show that when the fractal dimension D-f > 2.5, the adhesion force may vanish, or be at least strongly reduced. We consider the block-substrate pu ll-off force as a function of roughness, and find a partial detachment tran sition preceding a full detachment one. The theory is in good qualitative a greement with experimental data. (C) 2001 American Institute of Physics.