Photo-induced living/controlled surface radical grafting polymerization and its application in fabricating 3-D micro-architectures on the surface of flat/particulate organic substrates

This feature article covers the fundamental chemistry and applications of photo-induced living surface grafting polymerization. The mechanism of activation of inert alkyl C H bonds of polymer substrates, the structures of the active free radical and reversible dormant species, the modes of the grafting chain growth (including linear, branched and cross-linked variants), and the role of spatial effect are discussed. Two technologies, i.e., 1-step and 2-step processes, their features and applications in fabricating polymer brushes with precisely controlled patterns, desired functions, branched and block grafting chains on planar substrates, and polymer lamination are presented. The fabrication of 3-dimensional covalently bonded polymer particles, such as nano-sized polymer particle monolayers (with uniform and bimodal distributions), discrete solid and hollow polymer particles of micrometer size, and multilayer polymer particles on polymeric substrates are also introduced. In the last part, the application of photo-induced living surface grafting polymerization in non-planar surface modifications, such as the preparation of core-shell polymer particles, Janus particles and cross-linked hydrogels with hairy polymer chains is summarized. (C) 2011 Elsevier Ltd. All rights reserved.