The scientific and technical history of polymerization can be divided into three periods

which will be illustratedfor emulsion polymerization. The first period was when emulsion polymers were originally produced

and was developed asan attempt to copy natural rubber latex. Indeed

the natural process is quite different from the synthetic process of emulsionpolymerization

which in fact does not even need an emulsion to be present: the term is a misnomer! The results were functional but limited.In the second period

the first theories appeared

and a huge range of products was made for surface coatings

adhesives

commodity polymers such as SBR

neoprene

etc.The work of the outstanding pioneers was based on limited types of experimental data

and some suppositions are now seen to be incorrect.Nevertheless

many excellent products were made and have evolved to many materials currently in everyday use.The third period of emulsion polymerization is now dawning.The scientific efforts of many teams over previous decades

aided by the advent of new physical techniques for investigation

have resulted in better understanding of the fundamentals of emulsion polymerizations.Some examples from the author's group involve creating novel materials using controlled seeded emulsion polymerization from natural rubber latex and other polyenes.Latex topology and controlled free-radical chemistry can be combined to produce a )a comb polymer with hydrophobic backbone and hydrophilic "teeth"

or b )with sufficient in situ compatibilizer between two otherwise incompatible polymers to yield a spatially uniform material down to the nanostructure level

and c)to produce controlled nanostructures.