The CNRS Institute of Chemistry welcomes Krzysztof Matyjaszewski as Ambassador of Chemical Sciences in France

What is Atom Transfer Radical Polymerization (ATRP) and why is it so useful?

Free radical polymerization is the simplest addition reaction to create long macromolecules, called polymer chains, from small base molecules: monomers. Widely used to synthesize plastics, it is an uncontrolled reaction that produces polymer chains of very disparate lengths and architectures. Polymer chemists have long strived to develop such simple yet controlled/living polymerization methods that would make it possible to prepare more complex macromolecules with better controlled length distribution and multiblock, branched or even star-shaped architectures.

These architectures indeed combine, on the scale of the same molecule, the properties of different polymers, such as hydrophobicity and hydrophilicity, hardness and elasticity, electrical conduction and insulation, optical activity, biodegradability, etc. Such copolymers find many applications in biocompatible devices, drug delivery, water treatment by flocculation, stabilizers and foaming agents for the cosmetics or food industry, lightweight impact-resistant materials, adhesives, paints…

ATRP is precisely such a catalytic process which makes it possible to make controlled/living the radical polymerization of vinyl monomers. It relies on the use of a readily available copper-based catalyst that intermittently puts a growing polymer chain to sleep. This regulation of the reactivity of the chains not only allows them to all grow at the same time while minimizing side termination reactions, but also to subsequently reactivate a chain for the addition of one or more other consecutive blocks of different monomers.

Since its discovery in 1995, what have been the most important developments in ATRP?

In our first experiments in 1995, we used 1% molar Cu catalyst. We have since developed much more active catalysts which make it possible to work with very low concentrations, of the order of one part per million, which is moreover easily extractable. However, termination reactions can never be totally avoided and it is necessary to continuously regenerate these catalysts during the reaction. Various mild reducing agents can be used for this, such as ascorbic acid, sugars, but also light, electric current or mechanical forces. This also allows excellent external spatio-temporal control over the polymerization and very safe polymerization processes.

Recently, we have extended this control to the use of visible or even infrared light and have also developed oxygen-tolerant systems that make ATRP possible in water and in the open air. These advances have allowed the synthesis of many molecules bioconjugated with nucleic acids, proteins and even exosomes by ATRP. Finally, we have also developed the priming of ATRP on surfaces or nanoparticles to functionalize them and increase their dispersibility, their lubricity or generate antifouling and antibacterial materials that can also respond to external stimuli.

Has this simple polymerization technique already been developed on an industrial scale?

Since 1995, more than 40,000 scientific papers on controlled radical polymerization have been published, more than half of them on various aspects of ATRP, and 2,000 patents issued. At Carnegie Mellon University, we created a consortium to facilitate the promotion of this work and the transfer of knowledge and technologies to industry. We already have 60 members from companies in the chemical sector in the United States, Japan, China, Korea, South Africa, Mexico and Western Europe, including 3 in France. Carnegie Mellon has signed 17 commercial licenses, and production of various advanced polymer materials by ATRP began in 2004 in Japan, the United States and Europe.

In 2019, the CNRS Institute of Chemistry initiated this program entitled “Ambassadors of Chemical Sciences in France”. Its ambition is to allow prestigious foreign researchers to visit a series of French laboratories active in their field. These visits not only include high-level lectures by the ambassador, but are also a good opportunity to establish preliminary contacts and foster international collaborations for the French laboratories visited. What do you expect from this program?

Along with Poland and the United States, France is my favorite country for many reasons related to culture, history, gastronomy, science and people. I have many very close friends in France. In my research team, I had the pleasure of welcoming 20 French students and postdocs. They then made very successful careers in French industry or academia, such as Pr. Mathias Destarac, Jean-François Lutz or Renaud Nicolaÿ. We have published together more than 50 articles and 40 others with my colleagues from Toulouse, Paris, Strasbourg, Montpellier or Marseille. This visit to France will give me the opportunity to discuss science, renew scientific and personal contacts, disseminate our research and, of course, enjoy the beautiful French culture and gastronomy.

*Initially planned for 2020, the visit has been postponed to this month of April due to the health crisis.

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The CNRS Institute of Chemistry welcomes Krzysztof Matyjaszewski as Ambassador of Chemical Sciences in France

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