Page 10 - Introduction to Colloid and Surface Chemistry

1 The colloidal state

Introduction

Colloid science concerns systems in which one or more of the
components has at least one dimension within the nanometre (10-9m)
to micrometre (lO-"m) range, i.e. it concerns, in the main, systems
containing large molecules and/or small particles. The adjective
'microheterogeneous' provides an appropriate description of most
colloidal systems. There is, however, no sharp distinction between
colloidal and non-colloidal systems.
The range of colloidal systems of practical importance is vast, as is
the range of processes where colloidsurface chemical phenomena are
involved.
Examples of systems which are colloidal (at least in some respects)
are:

Aerosols Foodstuffs
Agrochemicals Ink
Cement Paint
Cosmetics Paper
Dyestuffs Pharmaceuticals
Emulsions Plastics
Fabrics Rubber
Foams Soil
Examples of processes which rely heavily on the application of
colloid/surface phenomena are:

Adhesion Ore flotation
Chromatography Precipitation
Detergency Road surfacing