Made-to-order polymers attract interest

Chemists at the University of Warwick have collaborated to do something that nature does as a matter of routine but that man can only accomplish with great effort - make polymers to order.

For industry, the process of devising new polymers has until now been something of a lottery. Chemists could make new polymers in the laboratory, but the randomness of the construction process forced researchers to find applications for those new polymers afterwards.

With very pure materials and temperatures around -80 degrees C, this problem can be avoided but the cost of this approach is prohibitive on an industrial scale.

Now, however, organic and supramolecular chemists at the department of chemistry of the University of Warwick have collaborated to devise methods that can create advanced designer polymers to order in normal industrial conditions.

Warwick chemistry department researcher David Haddleton has discovered, and patented, a process which attaches one of a particular family of ligands (small molecules that bind to a particular metal atom) known as `Schiff Base ligands' to a form of copper.

This material can be used as an extremely effective catalyst which is both soluble in water and is able to maintain an equilibrium between the two forms of copper generated, and required, by this form of polymer manufacture.

Haddleton is now collaborating with two supramolecular chemists at Warwick, Andrew Marsh and Michael Hannon to create to order extremely advanced polymers. Marsh and Hannon have been experimenting with chemical `templates' that mimic the action of how nature creates its own polymers to order.

The extreme conditions that were once required to construct polymers to order (temperatures as low as -80 degrees C and violent snapping of molecular bonds thereby creating highly charged particles) made use of these templates impossible.

Haddleton's work has now produced a form of controlled polymerisation that can be carried out in a much less harsh environment, allowing the use of templates, and even combinations of metal-based catalysts, in patterns that will allow them to mechanically `weave' a polymer.

Together, the three researchers believe their processes can be used to produce tailored polymers for everything from contact lenses to polymers for drug release, allowing time specific release into the human body.

Companies currently examining their work include Courtaulds, Reichold and Zeneca. The three chemists intend to build on their research by setting up a `Centre for Supramolecular and Macromolecular Chemistry' within the University of Warwick's department of chemistry.

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