Ordered layers of monodispersive colloids

We discuss both organic and inorganic monodispersive colloids having diameters of the order of a few hundred nm. The use of emulsion polymerisation and the Stober technique to produce organic and inorganic particles respectively is described. The application of ordered layers of such particles in photonics is discussed with particular reference to obtaining a photonic bandgap and the theoretical treatments of this question are briefly reviewed. There follows a review of the principal methods which have been employed to form good ordered multilayers of these materials. The so called inverted structures made by filling the interstices of these multilayers with another compound and then etching out the original particles are described. The results of some of the more important optical studies of both original multilayers and inverted multilayers are given.