Ethyl methacrylate , anionic

Trialkylsilyl-protected oligo(ethylene glycol)methacrylates, 2- 2- (tert-butyldimethylsilyl)oxy]ethoxy ethyl methacrylate (1), and 2- 2-[2-[(ferf-butyldimethylsilyl)oxy] ethoxy] ethoxy ethyl methacrylate (2) (Scheme 7) were used for the synthesis of amphiphilic block copolymers by anionic poly-... 

Penultimate effects have been observed for many comonomer pairs. Among these are the radical copolymerizations of styrene-fumaronitrile, styrene-diethyl fumarate, ethyl methacrylate-styrene, methyl methacrylate l-vinylpyridine, methyl acrylate-1,3-butadiene, methyl methacrylate-methyl acrylate, styrene-dimethyl itaconate, hexafluoroisobutylene-vinyl acetate, 2,4-dicyano-l-butene-isoprene, and other comonomer pairs [Barb, 1953 Brown and Fujimori, 1987 Buback et al., 2001 Burke et al., 1994a,b, 1995 Cowie et al., 1990 Davis et al., 1990 Fordyce and Ham, 1951 Fukuda et al., 2002 Guyot and Guillot, 1967 Hecht and Ojha, 1969 Hill et al., 1982, 1985 Ma et al., 2001 Motoc et al., 1978 Natansohn et al., 1978 Prementine and Tirrell, 1987 Rounsefell and Pittman, 1979 Van Der Meer et al., 1979 Wu et al., 1990 Yee et al., 2001 Zetterlund et al., 2002]. Although ionic copolymerizations have not been as extensively studied, penultimate effects have been found in some cases. Thus in the anionic polymerization of styrene t-vinylpyri-dine, 4-vinylpyridine adds faster to chains ending in 4-vinylpyridine if the penultimate unit is styrene [Lee et al., 1963]. 

The adsorption of block copolymers can be controlled by different stimuli, in particular by the pH since most of the brushes formed by block copolymers adsorption are polyelectrolyte brushes [129, 130], The group of Armes, for instance, studied the pH-controlled adsorption of a series of block copolymers [131, 132], In the case of copolymers bearing hydrophobic 2-(diethylamino)ethyl methacrylate groups (DEA) and a water-soluble zwiterionic poly(2-methacryloyl phosphoryl-choline) (MPC) block, they showed that at low pH the cationic DEA flatted to the anionic silicon surface while the MPC was in contact with the solution [132], At around neutral pH, micelles were formed in solution and adsorbed onto the surface because the DEA core was still weakly cationic. The MPC block formed the micelle coronas. Nevertheless, at higher pH the micelles became less cationic and the adsorption rate decreased. 

Polymerization or copolymerization of properly snbstitnted methacrylates is a direct and very effective strategy for the preparation of polymers grafted by a series of substituents. For instance, polymethacrylate containing amino groups was prepared by living LiCl-mediated anionic polymerization of 2-(dunethylamino)ethyl methacrylate (DMAEMA) °° and 2-(f-butylamino)ethyl methacrylate in THF at —78 °C. Mixtures of DMAEMA and tBuMA were also copolymerized . 

In contrast to GTP, certain functional groups are not tolerant of anionic polymerization, making it necessary to protect the group prior to polymerization and to deprotect after polymerization, which makes the process more complex. For example, 2-(trimethylsilyl-oxy)ethyl methacrylate and trimethylsUyl methacrylate were anionically polymerized as precursors of poly(2-hydroxyethyl methacrylate) and poly(methacrylic acid), respectively. 

Cationic polymers, such as poly(L-lysine) (PEL), polyethylenimine (PEI), chitosan, polyamidoamine (PAMAM) dendrimers, poly(2-dimethylamino) ethyl methacrylate, and polyphosphoesters, condense DNA to form compacted polyplexes. ° The size and the stability of polyplexes depend on the ratio of cations vs. anions, temperature, ionic strength, and the solvent. Stability of polyplexes can be enhanced by conjugating PEG to the polycations or by using PEG-containing block or graft polymers that form micelles. Small cationic peptides are also able to condense DNA, however, six-consecutive-cations is the minimal requirement to achieve this effectively. 

There are only a few cases in which polyelectrolyte stars have been prepared by the arm-first strategy. Qiao et al. prepared pH responsive poly(acrylic acid) stars by the MI method using atom transfer radical polymerization (ATRP), which was used to form layer-by-layer (LBL) polyelectrolyte multilayers with linear cationic polyelectrolytes [54], Matyjaszewski et al. obtained cationic poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) stars and anionic PAA stars also using the MI method, which formed all-star LBL layers [55], Ishizu et al. obtained... 

Electron-withdrawing substituents in anionic polymerizations enhance electron density at the double bonds or stabilize the carbanions by resonance. Anionic copolymerizations in many respects behave similarly to the cationic ones. For some comonomer pairs steric effects give rise to a tendency to altemate. The reactivities of the monomers in copolymerizations and the compositions of the resultant copolymers are subject to solvent polarity and to the effects of the counterions. The two, just as in cationic polymerizations, cannot be considered independently from each other. This, again, is due to the tightness of the ion pairs and to the amount of solvation. Furthermore, only monomers that possess similar polarity can be copolymerized by an anionic mechanism. Thus, for instance, styrene derivatives copolymerize with each other. Styrene, however, is unable to add to a methyl methacrylate anion, though it copolymerizes with butadiene and isoprene. In copolymerizations initiated by w-butyllithium in toluene and in tetrahydrofuran at-78 °C, the following order of reactivity with methyl methacrylate anions was observed. In toluene the order is diphenylmethyl methacrylate > benzyl methacrylate > methyl methacrylate > ethyl methacrylate > a-methylbenzyl methacrylate > isopropyl methacrylate > t-butyl methacrylate > trityl methacrylate > a,a -dimethyl-benzyl methacrylate. In tetrahydrofuran the order changes to trityl methacrylate > benzyl methacrylate > methyl methacrylate > diphenylmethyl methacrylate > ethyl methacrylate > a-methylbenzyl methacrylate > isopropyl methacrylate > a,a -dimethylbenzyl methacrylate > t-butyl methacrylate. 

Investigations were also made into surface nanostructures and their reconstruction behavior, by altering the outer environment using a series of block copolymers, namely PS-f)-poly(2-(perfluorooctyl)ethyl methacrylate) [96], PS-b-P(HEMA) [106, 107], and PS-f)-poly[(oligo(ethylene glycol) alkyl ether methacrylate), synthesized by anionic block copolymerization [116-120]. 

It has been reported in the literature that amphiphilic diblock copolymers can be synthesized by anionic polymerization by incorporating a new approach called oxyanion-initiated polymerization to combine tertiary amine methacrylates, such as 2-(N-morphoIino)ethyI methacrylate (MEMA), t-(butylamino)ethyl methacrylate (BAEMA), 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA), and 2-(N,N-diethylamino)ethyl methacrylate (DEAEMA). " " Such materials have been considered for various applications as adhesives, emulsion and dispersion stabilizers, wastewater treatment formulations, and biomaterials. 

Table 3. Anionic Polymerization of Ethyl Methacrylate Molecular Weight Control... 

Synthesis. Polyampholytes are most readily prepared by the direct statistical copolymerization of anionic and cationic monomers typically in aqueous media, via conventional free radical pol3unerization. Examples of such materials were first reported in the 1950s (240-244). Using this approach a wide range of copolymers and terpolymers, often with a neutral hydrophilic monomer such as acrylamide, have been reported. For example, early reports of statistical polyampholytes include the methacrylic acid-stat-2-(dimethylamino)ethyl methacrylate copolymers (245), from IZ and 2Z with 6Z and the iV,A(-diethylallylamine-stat-acrylic acid copolymers from IZ and 6Z (246). More recently, synthesis and properties of novel polyampholytic terpol5uners have been described (247-250). For example, the aqueous solution properties of novel ampholytic terpolymers of acrylamide, sodium 3-acrylamido-3-methylbutanoate 5Z and 3-(acrylamidopropyl)trimethylammonium chloride 8Z have been studied in detail (187). 

The synthesis of shell crosslinked knedel (SCK) micelles has been reported. Various applications, in areas as diverse as solubilisation, catalysis, fillers, coatings and delivery, have been proposed for these nanoparticles. However, in all studies the micelle cores are based on PS or polyisoprene and are therefore permanently hydrophobic. The synthesis of two new classes of SCK micelles with hydrophilic micelle cores are reported. Successftil shell crosslinking relies on. selective quatemisation of the A block, which comprises 2-(dimethylamino)ethyl methacrylate (DMAEMA) residues. The B block comprises 2-(N-morpholino)ethyl methacrylate (MEM A) and forms the micelle core. The second class is zwitterionic SCK micelles, prepared from precursor DMAEMA-2-tetrahydropyranyl methacrylate diblock copolymers. Depending on the synthetic route employed, two types of zwitterionic SCK micelles can be obtained Type I micelles, with anionic cores and cationic coronas, and Type II micelles, with cationic cores and anionic coronas. These zwitterionic SCK micelles exhibit isoelectric points in aqueous solution. 14 refs. 

The influence of the reaction conditions upon the stereochemistry of polymerization has been examined for a number of systems. The presence of a small amount of water increased the isotacticity of the polymerization of ethyl methacrylate in toluene at -78 °C. A new type of cyclic structure for polybutadiene-a substituted cyclopentane - was identified in polymer prepared using an organo-lithium initiator in the presence of tetramethylethylene diamine. The polymerization of 1-phenylbutadiene initiated by alkyl-lithium in hydrocarbon solvents results in 50—60% trans-, A, some 25% c/r-1,4, and 10— 25% 3,4 enchainment. When THF is employed as solvent, the corresponding values are about 80, 10, and 10%, respectively. The anionically-prepared polymers have structures very different from those formed cationically, which comprise lately 3,4 addition accompanied by extensive cyclization. The distribution of cis-and trans-1,4 structures in polyisoprene prepared using Bu Li in non-polar media has been shown by C n.ra.r. spectroscopy to be nearly random. The polymerization of fumaronitrile is initiated in benzene solution by the addition of butyl-lithium across one C N group in THF solution initiation is by transfer of an electron from BuLi. ... 

Detailed descriptions of polymerizations of MMA, ethyl aerylate, and butyl acrylate with either anionic or Lewis aeid eatalysts are given in Refs. [156] and [234]. Various other monomers, including lauryl, glycidyl, 2-ethylhexyl, 2-trimethylsiloxyethyl, sorbyl, allyl, and 2-(allyloxy)ethyl methacrylates have been employed in GTP [234]. Because of the milder conditions, this polymerization method is generally much more suitable than the classical anionic polymerization for monomers with reaetive functional groups. 

Electrotransport of anionic and neutral phenyl compounds such as benzoic acid (BA), benzenesulfonic acid (BSA), and phenyM,2-ethanediol (PhED) was studied using polyethylene films photografted with 2-(dimethylamino)ethyl methacrylate (DMAEMA). The BA and... 

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