Smart plastic innovators net Prime Minister’s Science Prize

Ezio Rizzardo and David Solomon are this year's recipients of the Prime Minister's Prize for Science. Credit: Prime Minister's Science Prizes/Bearcage

SYDNEY: Groundbreaking work in the field of custom polymer production has netted scientists David Solomon and Ezio Rizzardo one of Australia’s most prestigious awards.

Solomon, from the University of Melbourne and Rizzardo, from Australia’s national science agency, the CSIRO, have developed a method that allows customised polymer chains to be built, with applications in everything from extended-wear contact lenses and solar cells to improved drug delivery technology.

The two researchers were awarded the A$300,000 Prime Minister’s Prize for Science tonight at a ceremony in the Great Hall of Parliament House in Canberra. “Solomon and Rizzardo’s research in polymer chemistry has been truly transformative,” said Suzanne Cory, president of the Australian Academy of Science. “Their work is a marvellous example of how elegant fundamental science can also be of immense practical benefit.”

Chain reaction

Polymers are long chains of smaller, repeating molecules called monomers. Their underlying structure forms the basis of nylon clothing and Teflon cookware.

Prior to the efforts of Solomon and Rizzardo, the reactions that linked monomers units to form polymers were wild and uncontrollable. There was no reliable way to predetermine the order and type of monomer links that formed a polymer chain.

This all changed when the pair started studying the mechanisms of polymer construction using a type of compound known as a free radical. They found that they could limit the chain polymerisation reaction to two or three links by ‘capping’ these free radical compounds with a nitroxide molecule.

Contact lenses and solar cells

But the real excitement came when it was discovered that the nitroxide caps that prevented linking were able to be removed, thus enabling a previously unheard of level of control over monomer linkages.

Having determined that a reversible capping process was the best way to build customised polymer chains, Rizzardo and Solomon refined the process into the patented reversible addition-fragmentation chain transfer (RAFT) method. The implications of the method were not lost on the U.S. chemical giant DuPont, who signed them up to a developmental agreement worth hundreds of millions of dollars.

According to Rizzardo, some 60 companies around the world are currently using RAFT to build polymers with applications including extended-wear contact lenses, lubricants, solar cells, drug delivery and membranes for water desalination.

Humble beginnings

Solomon’s career had an unlikely start, working from the age of 16 at the paint factory that would become Dulux Australia. Every week the company would allow him one half-day off to study for his bachelor of science. Solomon eventually worked his way up through a PhD in organic chemistry, and it was during this that he became interested in polymers and began to develop theories regarding their reactions. But it was only when he joined CSIRO that he was able to probe the mechanisms behind their use.

At CSIRO, Solomon hired Rizzardo as a postdoctoral fellow, kick-starting their successful partnership. Rizzardo, who also took some time to find his way to polymer science, was initially interested in designing car motors and went on to study medicine, but balked at working on cadavers.

He then turned to chemistry, earning a PhD and working on a series of postdoctoral projects involving biologically active products before arriving at Solomon’s small polymer research group. It was there that he and Solomon developed the radical new way of investigating the reactions that formed polymers which would lead to their most significant discovery.

“I regard it as a great honour to have been awarded the nation’s pre-eminent prize for science. I am very happy, not only for myself, but also for the many people who worked for me and with me over the years,” said Rizzardo.