The University of Tokyo, Japan

A chemist sees a commercial future for designer polymers.

Just over a decade ago, a discovery in polymer chemistry triggered explosive progress in macromolecular engineering. A trio of papers published last year will, I think, help to usher the benefits of this development into industry.

The results concern chemists’ ability to grow tailored polymers, which have controllable size and architecture. Such polymers are becoming more and more important as major players in the burgeoning field of nanotechnology.

The original breakthrough was the development of a method known as atom-transfer radical polymerization, which made it easy to grow polymers to design.

The method uses a catalyst containing a transition metal, such as copper. The catalyst interacts with the polymer, turning it briefly into a reactive radical that will bind another monomer. Each molecule grows one step at a time, so producing polymers with uniform properties.

A problem with this method has been the large amount of catalyst needed to drive the reaction — leaving residues that are costly to remove. Two recent papers do away with this concern, cutting the concentration of catalyst required by up to 1,000-fold (W. Jakubowski & K. Matyjaszewski Angew. Chem. Int. Edn 45, 4482–4486, 2006; K. Matyjaszewski et al. Proc. Natl. Acad. Sci. USA 103, 15309–15314, 2006).

Another advance, which takes advantage of an unexpectedly active oxidation state of the catalyst’s copper, will allow production of polymers with an ultra-high molecular weight and a narrow molecular-weight distribution (V. Percec et al. J. Am. Chem. Soc. 128, 14156–14165, 2006).

Some chemical companies are already setting up industrial plants to make polymers by atom-transfer radical polymerization. These developments mean that more are sure to follow.