Carnegie Mellon University

About Atom Transfer Radical Polymerization (ATRP)

Atom Transfer Radical Polymerization (ATRP) is among the most effective and most widely used methods of controlled radical polymerization (CRP). ATRP allows scientists to easily form polymers by putting together component parts, called monomers, in a controlled, piece-by-piece fashion. Assembling polymers in such a manner has allowed scientists to create a wide range of polymers with site specific tailored functionalities targeting specific properties for high value applications. For example, polymers created using ATRP have been used for coatings and adhesives, and are currently under investigation for use in the medical and environmental fields.

Until the discovery of ATRP, polymer chemists were severely limited in their ability to control the composition and architecture of macromolecules, making it difficult to provide materials with highly specific, uniform characteristics. Since the mid-1950s, many chemists attempted to develop a “living” or controlled radical polymerization process that would create well-defined polymers in a simple, inexpensive manner. In the mid-1990s, several laboratories across the world surmounted this vexing problem by developing CRP methods. These techniques allow synthesis of fundamentally new materials with complex, well-defined nanoscale architectures. In 1995, Carnegie Mellon University Professor Krzysztof Matyjaszewski discovered one of the first — and most robust — CRP methods, copper-mediated ATRP. The seminal paper was published in the Journal of the American Chemical Society and has been cited over 3,000 times and the initial 1995 patent applications close to 200 times.

ATRP differs significantly from earlier conventional radical based polymer manufacturing methods by allowing scientists to produce complex polymer structures using a special catalyst that adds one or a few subunits (monomers) at a time to a growing polymer chain. This living, synthetic process can be shut down or re-started at will, depending on how the temperature and other conditions of the reaction are varied. ATRP is an exceptionally robust way to uniformly and precisely control the chemical composition and architecture of polymers as well as the uniform growth of every polymer chain, while employing a broad range of monomers.

Key to ATRP’s success is that the process is easily conducted in available industrial equipment. Much of its research progress and commercial success can be attributed to two research Consortia Matyjaszewski has initiated and led. These two highly successful consortia have allowed companies to quickly incorporate the latest ATRP methodologies into the development of new products for their specific markets. These Consortia have comprised more than 50 multinational chemical companies from across the world who can send their employees to be trained in the latest ATRP procedures in Matyjaszewski’s laboratory.

ATRP technology developed by Matyjaszewski has already been licensed to nine international companies, which started production of ATRP-based polymers in Japan, Europe and the United States in 2004. ATRP has been successfully used to create better pigment dispersants for inkjet printing, cosmetics, chromatographic packings, adhesives and sealants for self-cleaning windows, among others. Some other applications that are being evaluated include drug delivery methods, coatings for cardiovascular stents, scaffoldings for bone regeneration, biocidal surfaces, degradable plastics and others in the optoelectronic and automotive industries.