Short-range attractions between two colloids in a lipid monolayer

Two mobile cylinders embedded in a lipid monolayer exhibit two types of short-range attractions, a depletion-induced attraction in the range r<sigma(L), where sigma(L) is the diameter of a lipid and r is the distance between the surfaces of the two cylinders, and a fluctuation-induced attraction in the range 1<r/sigma(L)<4. Using Monte Carlo methods we have calculated the force between the cylinders for various diameters sigma(p). Evidence is given that the strength of attraction increases with decreasing curvature of the cylinders. (C) 1997 American Institute of Physics.