Sticky Surfaces: Sphere-Sphere Adhesion Dynamics

TL;DR

This paper introduces a multi-scale model to analyze how microscopic ligand kinetics and ionic surface potentials influence the formation and size distribution of particle aggregates in fluid environments.

Contribution

It provides a novel multi-scale theoretical framework linking micro-scale ligand interactions and macro-scale floc size distribution in fluid-immersed spherical particles.

Findings

Elastic ligands promote larger floc aggregates.

Ionic composition of the fluid enhances floc formation.

Surface potentials significantly affect aggregation dynamics.

Abstract

We present a multi-scale model to study the attachment of spherical particles with a rigid core, coated with binding ligands and in equilibrium with the surrounding, quiescent fluid medium. This class of fluid-immersed adhesion is widespread in many natural and engineering settings. Our theory highlights how the micro-scale binding kinetics of these ligands, as well as the attractive / repulsive surface potential in an ionic medium effects the eventual macro-scale size distribution of the particle aggregates (flocs). The results suggest that the presence of elastic ligands on the particle surface allow large floc aggregates by inducing efficient inter-floc collisions (i.e., a large, non-zero collision factor). Strong electrolytic composition of the surrounding fluid favors large floc formation as well.