Chapter List

2.1 Introduction

The structure displayed by assemblies of colloidal particles, whether in three dimensions (3-D) or in two dimensions (2-D), is an important aspect in many industrial processes and products, e.g. waste-water treatment, paints and ceramics, but also for the assembly of new materials.1 4 Colloidal particles can be made to organise into ordered arrays or to attain heterogeneous structures with different degrees of disorder. The control of colloidal structure formation starts with the particle interactions (attractive or repulsive) and colloidal dynamics. These interactions balance against thermal forces and external influences such as gravity and applied force fields to determine what configurations the particles will adopt, e.g. network-like, random or ordered configurations (see Figure 2.1).

Figure 2.1: Examples of colloidal structures produced by spherical silica particles with a diameter of 1.97 ?m trapped at an air liquid surface; (a) disordered network of octyl-coated silica that aggregate at the air toluene surface; (b) low density ordered structure caused by a temporal long-range repulsion between the silica particles; (c) dense particle monolayer of octadecyl-coated particles that have been forced to close pack by an increasing surface fraction. (a) and (b) taken from Ref. [45]; with permission of Academic Press; (c) taken from Ref. [22]; with permission of the American...