Atom transfer radical polymerization synthesized

Another application of pH-responsive polymers was shown by de Groot et al. (2013), as shown in Figure 5.11. Surface-initiated atom transfer radical polymerization synthesized PMAA brushes were used to create pH-responsive nanoporous platforms. It was shown that at pH 4, gating of ions was allowed through the nano channels, whereas at pH 8, the pores were closed. The authors predict that their pH-re-sponsive channels have potential as electrochemical biosensors and in bioseperation technology. 

In 2003, the van Hest group produced elastin-based side-chain polymers [123]. This research was motivated by the demonstration of the occurrence of an inverse temperature transition in a single repeat of VPGVG [124]. A methacrylate-functionalized VPGVG was synthesized and used as a monomer to perform atom transfer radical polymerization (ATRP) to produce homopolymers (Fig. 16b) or... 

Block copolymers were synthesized by a combination of fipase-catalyzed polymerization and atom transfer radical polymerization (ATRE). " " At first, the polymerization of 10-hydroxydecanoic acid was carried out by using lipase CA as catalyst. The terminal hydroxy group was modified by the reaction with a-bromopropionyl bromide, followed by ATRP of styrene using CuCE2,2 -bipyridine as catalyst system to give the polyester-polystyrene block copolymer. Trichloromethyl-terminated poly(e-CL), which was synthesized by lipase CA-catalyzed polymerization with 2,2,2-trichloroethanol initiator, was used as initiator for ATRP of styrene. 

Dynamic formation of graft polymers was synthesized by means of the radical crossover reaction of alkoxyamines by using the complementarity between nitroxide radical and styryl radical (Fig. 8.13) [40]. Copolymer 48 having alkoxyamine units on its side chain was synthesized via atom transfer radical polymerization (ATRP) of TEMPO-based alkoxyamine monomer 47 and MMA at 50°C (Scheme 8.9). The TEMPO-based alkoxyamine-terminated polystyrene 49 was prepared through the conventional nitroxide-mediated free radical polymerization (NMP) procedure [5,41], The mixture of copolymers 48 and 49 was heated in anisole... 

Zhang H, Fijten MWM, Hoogenboom R, Schubert US (2003) Atom-transfer radical polymerization of methyl methacrylate utilizing an automated synthesizer. ACS Symp Ser 854 193-205... 

The ruthenium indenylidene Schiff base complexes XXVIIIa and XXVIIId, synthesized by Verpoort, were evaluated in atom-transfer radical polymerization of methyl methacrylate. The polymerization was initiated by ethyl 2-bromo-2-methyl-... 

Controlled free-radical polymerization methods, like atom-transfer radical polymerization (ATRP), can yield polymer chains that have a very narrow molecular-weight distribution and allow the synthesis of block copolymers. In a collaboration between Matyjaszewski and DeSimone (Xia et al., 1999), ATRP was performed in C02 for the first time. PFOMA-/)-PMMA, PFOMA-fr-PDMAEMA [DMAEMA = 2-(dimethylamino)ethyl methacrylate], and PMMA-/)-PFOA-/)-PM M A copolymers were synthesized in C02 using Cu(0), CuCl, a functionalized bipyridine ligand, and an alkyl halide initiator. The ATRP method was also conducted as a dispersion polymerization of MMA in C02 with PFOA as the stabilizer, generating a kine-... 

Triphenylamine derivatives are known to be efficient hole transport materials and are widely used in organic light-emitting devices. Thelakkat et al. reported the synthesis of a 2,2-bipyridine ligand capped with polyfvinyl-triphenylamine) at both ends.97 The polymer chain was synthesized by the atom transfer radical polymerization of 4-bromostyrene using 4,4-bis (chloromethyl)bipyridine as the initiator (Scheme 18). The bromide groups were then replaced by diphenylamine in the presence of palladium catalyst. Polymer 33 was then obtained by the metalation reaction. 

These methods are based on the idea of establishing equilibrium between the active and dormant species in solution phase. In particular, the methods include three major techniques called stable free-radical polymerization (SFRP), atom transfer radical polymerization (ATRP), and the degenerative chain transfer technique (DCTT) [17]. Although such syntheses pose significant technical problems, these difficulties have all been successively overcome in the last few years. Nevertheless, the procedure of preparation of the resulting copolymers remains somewhat complicated. 

A block copolymer consisting of a SCLCP-block of monomer XXVII with a laterally-attached mesogenic unit, and butyl-acrylate, was synthesized using a combination of ROMP and atom transfer radical polymerization (ATRP) (Fig. 16) [81]. 

A disadvantage of traditional acrylamide polymerization reactions is the heterogeneity of the products that result. A radical polymerization method that produces polymers of similar structure but that are much more homogeneous is atom-transfer radical polymerization (ATRP) [155,156]. ATRP has been used to synthesize carbohydrate-substituted polymers with low polydispersities [157,158,159,160,161]. Materials that display sugar residues such as glu-cofuranose [160], glucopyranose [161], and A-acetyl-D-glucosamines [159]. 

The PDEA-PEG block copolymer was synthesized by a typical atom-transfer radical polymerization (ATRP) using PEG as the macroinitiator (Scheme 10.4). This block copolymer formed micelles with diameters less than lOOnm, which is ideal for endocytosis. The dissolution of the micelles at low pH was monitored using A-phenyl-2-naphthylamine (PNA) as a florescent probe which has a low fluorescent activity in hydrophilic environments. The PDEA-PEG micelle was loaded with PNA. Its flnorescence was monitored as a fnnction of the solution pH. Eigure 10.18 suggests that the micelles dissolved at a pH about 6.0, which implies that the nanoparticles can... 

Figure 3.2.6). Narrowly dispersed polystyrene (synthesized by atom transfer radical polymerization [polydispersity < 1.1]) was end fnnctionized with a phosphonate moiety that binds strongly to titanium oxide. The combination of narrowly dispersed titanium oxide and narrowly dispersed phosponate-terminated polystyrene generates a narrowly dispersed core-shell architecture as measured by dynamic light scattering, which can be spun into dielectric films. The covalent coating of polystyrene around titanium oxide is helpful at preventing aggregation of the nanoparticles in organic dispersion and in thin films.

An approach similar to the previous divergent grafting-from method also served to synthesize dendrigraft poly(L-lysine) by ring-opening polymerization [111], styrene homopolymers and styrene-methacrylate copolymers by a combination of stable free-radical polymerization and atom transfer radical polymerization (ATRP) [112], and copolymers of 2-hydroxyethyl methacrylate with styrene or ferf-butyl methacrylate by ATRP [113]. 

The formation of living polymer obeys a completely different mechanism than faced in radial polymerization. With living polymers, highly uniform materials can be synthesized. Living polymerization includes not only anionic polymerization but also atom transfer radical polymerization, living controlled free radical polymerization. 

AYD Aydin, S., Erdogan, T., Sakar, D., Hizal, G., Cankurtaran, O., Tunca, U., and Karaman, F., Detection of microphase separation in poly(tert-butyl acrylate-Z>-methyl methacrylate) synthesized via atom transfer radical polymerization by inverse gas chromatography, Eur. Polym. J., 44, 2115, 2008. 

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