Real and Apparent Sources of Polydispersity in Molecular Weight Distributions from Radical Polymerization
A Holy Grail of the macromolecular chemist is to achieve the ‘purity’ in size of micromolecular chemistry. In a real sense this quest is like that of Sisyphus in Greek mythology, who was eternally condemned to rolling a boulder uphill. The macromolecular chemist will also never reach the top of the hill, because the statistical nature of all polymerizations makes true monodispersity in size impossible to achieve by chemical means. Be that as it may, the advent of living radical polymerization (LRP) has reawakened the dream, and over the last decade there have been literally tens of thousands of papers in which workers have used this tremendous new chemical principle to strive towards the magical polydispersity index of 1. Given this it is timely to take stock of recent investigations into factors that influence the polydispersity of molecular weight distributions from radical polymerization.