Depletion forces between non-spherical objects

Abstract

We extend the insertion approach for calculating depletion potentials to the case of non-spherical solutes. Instead of a brute-force calculation we suggest to employ the recently developed curvature expansion of density profiles close to complexly shaped walls. The approximations introduced in the calculation by the use of the curvature expansion and of weight functions for non-spherical objects can be tested independently. As an application for our approach we calculate and discuss the depletion potential between two hard oblate ellipsoids in a solvent of hard spheres. For this system we calculate the entropic force and torque acting on the objects.