Polymer brushes atom transfer radical

Pyun, J., Kowalewski, T. and Matyjaszewski, K. (2003) Synthesis of polymer brushes using atom transfer radical polymerization. Macromol. Rapid Commun., 24, 1043-1059. 

Qin, S., et al., Polymer brushes on single-walled carbon nanotubes by atom transfer radical polymerization ofn-butyl methacrylate. Journal of the American Chemical Society, 2003. 126(1) p. 170-176. 

While in most of the reports on SIP free radical polymerization is utihzed, the restricted synthetic possibihties and lack of control of the polymerization in terms of the achievable variation of the polymer brush architecture limited its use. The alternatives for the preparation of weU-defined brush systems were hving ionic polymerizations. Recently, controlled radical polymerization techniques has been developed and almost immediately apphed in SIP to prepare stracturally weU-de-fined brush systems. This includes living radical polymerization using nitroxide species such as 2,2,6,6-tetramethyl-4-piperidin-l-oxyl (TEMPO) [285], reversible addition fragmentation chain transfer (RAFT) polymerization mainly utilizing dithio-carbamates as iniferters (iniferter describes a molecule that functions as an initiator, chain transfer agent and terminator during polymerization) [286], as well as atom transfer radical polymerization (ATRP) were the free radical is formed by a reversible reduction-oxidation process of added metal complexes [287]. All techniques rely on the principle to drastically reduce the number of free radicals by the formation of a dormant species in equilibrium to an active free radical. By this the characteristic side reactions of free radicals are effectively suppressed. 

SIP-driven polymer brush library fabrication leverages the fact that the polymerization initiation species are permanently bound to the substrate. Since the initiators are tethered, controlled delivery of monomer solution to different areas of the substrate results in a grafted polymer library. In NIST work, initiators bound via chlorosilane SAMs to silicon substrates were suitable for conducting controlled atom transfer radical polymerization (ATRP) [53] and traditional UV free radical polymerization [54, 55]. Suitable monomers are delivered in solution to the surface via microfluidic channels, which enables control over both the monomer solution composition and the time in which the solution is in contact with the initiating groups. After the polymerization is complete, the microchannel is removed from the substrate (or vice versa). This fabrication scheme, termed microchannel confined SIP ([t-SIP), is shown in Fig. 10. In these illustrations, and in the examples discussed below, the microchannels above the substrate are approximately 1 cm wide, 5 cm long, and 300-500 [tm high. 

Granville AM, Boyes SG, Akgun B, EosterMD, Brittain WJ. Synthesis and characterization of stimuli-responsive semifluorinated polymer brushes prepared by atom transfer radical polymerization. Macromolecules 2004 37 2790-2796. 

Polymer brushes are polymers tethered to a surface via one end. The connection to the surface can be covalent or non-covalent, and the brushes can be made via grafting to or grafting from the surface. In the past few years, there has been considerable interest in the growth of polymer brushes via surface-initiated polymerisations from (patterned) initiator-functionalised SAMs.62,63 For example, we have recently shown that surface confined Atom Transfer Radical Polymerisations (ATRP) in aqueous solvents leads to rapid and controlled... 

Thermally responsive polymers, such as poly( V-isopropyl acrylamide) (NI-PAm), have also been studied extensively for applications related to those previously discussed [112], De las Heras et al. described the synthesis and patterning of NIPAm brushes on SAMs and their subsequent performance during temperature-dependent adhesion assays of BSA and Streptococcus mutans (Fig. 7). The authors employed p.CP to pattern features of hydrophobic hexadecanethiol and backfilled the surface with an initiator-functionalized alkanethiol. Polymer brushes were grown via surface-initiated atom transfer radical polymerization (ATRP). FITC-BSA was then... 

Ramakrishnan A, Dhamodharan R, Ruhe J. Growth of poly(methyl methacrylate) brushes on silicon surfaces by atom transfer radical polymerization. J Polym Sci Pol Chem 2006 44 (5) 1758-69. 

Wang YP, Pei XW, He XY, Lei ZQ. Synthesis and characterization of surface-initiated polymer brush prepared by reverse atom transfer radical polymerization. Eur Polym J 2005 41 (4) 737-41. 

Piech M, Bell NS. Controlled synthesis of photochromic polymer brushes by atom transfer radical polymerization. Macromolecules 2006 39(3) 915—22. 

Shah RR, Merreceyes D, Husemann M, Rees I, Abbott NL, Hawker CJ, et al. Using atom transfer radical polymerization to amplify monolayers of initiators patterned by microcontact printing into polymer brushes for pattern transfer. Macromolecules 2000 33(2) 597—605. 

Desai SM, Solanky SS, Mandale AB, Rathore K, Singh RP. Controlled grafting of N-iso-propylacrylamide brushes onto self-standing isotactic polypropylene thin films surface initiated atom transfer radical polymerization. Polymer 2003 44(25) 7645—9. 

Paripovic D, Klok H-A (2011) Improving the stability in aqueous media of polymer brushes grafted from silicon oxide substrates by surface-initiated atom transfer radical polymerization. Macromol Chem Phys 212 950... 

Boyes, S.G. Akgun, B. Brittain, W.J. Foster, M.D. Synthesis, characterization, and properties of polyelectro-1)46 block copol3fmer brushes prepared by atom transfer radical pol3fmerization and their use in the synthesis of metal nanoparticles. Macromolecules 2003, 36, 9539. Neugebauer, D. Zhang, Y. Pakula, T. Matyjaszewski, K. Heterografted PEO-Pn BA brush copolymers. Polymer 2003, 44, 6863. 

Recently, surface modification techniques for polymer chains have progressed a great deal with the development of a new polymer synthesis method. In particular, surface-initiated atom transfer radical polymerization (SI-ATRP) is one of the most effective modification methods for preparing a well-defined dense polymer brush structure, or polymer brush, on solid substrates. Thus, a self-oscillating polymer brush prepared by SI-ATRP can be expected to create a novel self-oscillating surface with autonomous function, which will lead to potential applications in transporting systems for nanomaterials of flow control in microfluidics. 

Next, in order to demonstrate the efficacy of this cell surface engineering approach, cell microarrays were prepared using a micropattemed poly(2-methacryloyloxyethyl phosphorylcholine [MPC]) (PMPC) polymer brush surface as the substrate. PMPC brushes were prepared on a silicon (Si) wafer via surface-initiated atom transfer radical polymerization, as previously described elsewhere [35]. Selective decomposition of the initiators immobilized on the Si wafer using UV light irradiation resulted in micropatterning of the... 

Electrochemical Sidewalls radical addition Substituted aryl groups In situ formation of radical species by electron transfer from CNTs at constant potential/current Attachment of MNps [69] Grafting of polymer brushes via atom transfer radical polymerization [70] Immobilization of hydrogenase enzyme [71] and DNA [72]... 

Mu B, Shen RP, Liu P (2009) Crosslinked polymeric nanocapsules from polymer brushes grafted silica nanoparticles via surface initiated atom transfer radical polymerization. Colloid SurfB 74 511-515... 

Kong, X. Kawai, T. Abe, J. lyoda, T. Amphiphilic polymer brushes grown from the silicon surface by atom transfer radical polymerization. Macromolecules 2001,34, 1837— 1844. 

Ayres, N. Boyes, S. G. Brittain, W. J. Stimuli-responsive polyelectrolyte polymer brushes prepared via atom-transfer radical polymerization. Langmuir 2007, 23, 182-189. 

Xu D, Yu WH, Kang ET, Neoh KG (2004) Functionalization of hydrogen-terminated silicon via surface-initiated atom-transfer radical polymerization and derivatization of the polymer brushes. J Colloid Interface Sci 279 78... 

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