Polymer brushes can be prepared in a grafting-from manner using surface-initiated polymerizations such as atom-transfer radical polymerization (SI-ATRP) . However, conventional ATRP has a couple of drawbacks, most notably the fact that it is oxygen-sensitive and thus has to be carried out under anaerobic conditions. This complicates synthesis of polymer brushes using ATRP significantly in a few ways. Most import-antly, it requires the use of airtight reaction vessels and rigorous deoxygenation of reaction solutions (e.g. by purging with an inert gas like nitrogen). Even small amounts of oxygen inadvertently introduced into the system (e.g. by inadequate deoxygenation of a reactant, or an air leak) will result into termination of the polymerization reaction. Moreover, it means scaling up to larger surfaces is difficult, since equally large air-tight glassware (to contain them) is required, and conversion is extremely low; only a small fraction of monomer in the solution is polymerized on the surface. Air-tolerant polymerization methods greatly simplify polymer brush synthesis , and make it accessible to more people, as well as much more convenient for experienced chemists. Air-tolerant ATRP methods, most of which are based on activator regeneration, have been developed (initially for solution ATRP, and later adapted to surface-initiated ATRP) by the Matyjaszewski group .