Atom Transfer Radical Polymerization (IMAGE) University of California - Santa Barbara Caption Metal-free atom transfer radical polymerization uses an organic-based photocatalyst. Credit Peter Allen, UCSB Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.