# Interaction Forces between Colloidal Particles in Liquid: Theory and Experiment

## Overview

- [1] Yuncheng Liang, Nidal Hilal, Paul Langston, and Victor Starov, Advances in Colloid and Interface Science 134-135, 151-166 (2007).
**Keywords:**van der Waals Forces, Electric Double Layer Forces, Solvation Forces, Hydrophobic Forces, Steric Forces, Atomic Force Microscopy, Surface Forces Apparatus

## Summary

This is a review article summarizing the major findings and contributions of 158 publications. Many of the major contributions to this field were made very recently. This review article includes information on the theories of colloidal interaction forces, experiments testing them, and the historical development/breakthroughs in the field.

Timeline:

5 forces:
**1) van der Waals Forces**

Equation 1 Interaction energy between two spheres:

<math>V_A(D)=-\frac{A_H}{6}\left(\frac{2a^2}{D^2+4aD}+\frac{2a^2}{(D+2a)^2}+ln\left(1-\frac{4a^2}{(D+2a)^2}\right)\right)</math>

<math>A_H</math>= Hamaker Constant <math>a</math>= Sphere Radius <math>D=</math> Interparticle Distance

2) Electric Double Layer Forces

<math>V_R=\frac{128\pi a_1 a_2 n_\infty kT}{(a_1+a_2)\kappa^2} \gamma_1 \gamma_2 e^{(-\kappa h)}</math>

3) Solvation Forces

4) Hydrophobic Forces

5) Steric Forces

The second half of this review article discusses experimental evidence for or against the above five forces. There are still open questions in this field because some of the experimental evidence does not agree with the current theories.

## Soft Matter Details

**Surface Properties:**

Chemistry/soft matter, colloids, foams, stabilization

**Experimental Methods:**

AFM SFA

**History:**

How much does knowing the historical development help us in doing current science?