Depletion forces between non-spherical objects

TL;DR

This paper develops a method to calculate depletion forces between non-spherical objects using curvature expansion, enabling more efficient and accurate modeling of complex-shaped particles in a solvent.

Contribution

It introduces a curvature expansion approach for depletion potential calculations involving non-spherical solutes, extending previous methods.

Findings

Calculated depletion potential between two hard oblate ellipsoids.

Determined entropic force and torque on non-spherical objects.

Validated the approach with specific non-spherical geometries.

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.