Copolymers with substituted methacrylate

In this article we will describe two different types of positive electron-beam resists, which were briefly reported in our previous communications (2,3). One is the homopolymer or copolymer with methyl methacrylate and a-substituted benzyl methacrylate, which forms methacrylic acid units in the polymer chain on exposure to an electron-beam and can be developed by using an alkaline solution developer. In this case, the structural change in the side group of the polymer effectively alters the solubility properties of the exposed polymer, and excellent contrast between the exposed and unexposed areas is obtained. The other is a self developing polyaldehyde resist, which is depolymerized into a volatile monomer upon electron-beam exposure. The sensitivity was extremely high without using any sensitizer. 

It has also been reported the mechanism on dewetting by increasing temperature of perfluoroalkyl methacrylate as homo- and copolymer with methyl methacrylate films. The following qualitative model has been proposed (Sheiko et al, 1996). As has already been stated, perfluoroalkyl-substituted polymethacrylates have been shown to form ordered structures based on the crystallisation of the perfluoroalkyl side chains and the incompatibility of the fluorinated and the hydrocarbon segments. 

II. B polyethylene glycol, ethylene oxide, polystyrene, diisocyanates (urethanes), polyvinylchloride, chloroprene, THF, diglycolide, dilac-tide, <5-valerolactone, substituted e-caprolactones, 4-vinyl anisole, styrene, methyl methacrylate, and vinyl acetate. In addition to these species, many copolymers have been prepared from oligomers of PCL. In particular, a variety of polyester-urethanes have been synthesized from hydroxy-terminated PCL, some of which have achieved commercial status (9). Graft copolymers with acrylic acid, acrylonitrile, and styrene have been prepared using PCL as the backbone polymer (60). 

By employing anionic techniques, alkyl methacrylate containing block copolymer systems have been synthesized with controlled compositions, predictable molecular weights and narrow molecular weight distributions. Subsequent hydrolysis of the ester functionality to the metal carboxylate or carboxylic acid can be achieved either by potassium superoxide or the acid catalyzed hydrolysis of t-butyl methacrylate blocks. The presence of acid and ion groups has a profound effect on the solution and bulk mechanical behavior of the derived systems. The synthesis and characterization of various substituted styrene and all-acrylic block copolymer precursors with alkyl methacrylates will be discussed. 

Radical copolymerization of diaryl nitrones, such as a-(2-hydroxyphenyl)-A-(2,6-dimethylphenyl) nitrone (HDN), a-(2-hydroxy-4-methacryloyloxyphenyl)-N -(2,6-dimethylphenyl) nitrone (HMDN), and a-(2-hydroxy-4-methacryloyloxy-phenyl)-A-phenylnitrone (HMPN) (Fig. 2.30), with methyl methacrylate leads to copolymers in good yields with considerable quantities of hydroxy substituted diaryl nitrone pendants. The presence of photoactive nitrone pendants in these copolymers allows one to control photochemically the refractive index of polymethyl methacrylate films (468, 700, 701). 

The a transition is not included in the considered temperature range. For CMI contents equal to or higher than 10%, two transitions are observed. At low temperatures a shoulder is present, whose extent increases with increasing CMI (y transition). Studies performed on copolymers with maleimide unit N-substituted by isopropyl or phenyl groups [79] do not show this low-temperature transition, which appears to be specific for cyclohexylmaleimide. Such a situation is analogous to the one encountered with poly(cyclohexyl methacrylate) described in Sect. 3. Consequently, this low-temperature transition is assigned to the internal motion of the cyclohexyl ring, i.e. the chair-chair inversion represented in Fig. 7. 

Dendrons attached as side chains on linear polymer chains behave different from free dendrimers and dendrons. Block copolymers, poly(3,5-bis(3,5-bis (benzyloxy)benzyloxy)-benzyl methacrylate-random-methacrylic acid)-block-poly(2-perfluorooctylethyl acrylate), possess poly(benzylether) dendrons and perfluorinated alkyl chains in their side chains (Fig. 4) [85], While an LB film of a copolymer with a medium substitution fraction of poly(benzylether) dendron side chain in poly(methacrylic acid) displays flat surface, a copolymer with high fraction of poly(benzylether) dendron side chains produces the zone texture. Dendron rich blocks are hydrophobic and oleophilic but perfluorinated blocks are solvophobic. Therefore, in this case, the solvophobicity-to-solvophilicity balance must be considered. As a result, copolymers with medium fraction of dendron are laid on solid substrate, but dendron blocks of copolymers with high fraction prefer to arrange at air side of air/ water interface and the fluorocarbon blocks are enforced to exist close to water subphase, resulting in the zone texture [86]. These situations of molecular arrangements at air/water interface are kept even after transfer on solid substrate. By contrast, when perfluorooctadecanoic acids are mixed with block copolymers with high dendron fraction, the flat monolayers are visualized as terrace [87], The monolayers are hierarchized into carboxyl, per-fluoroalkyl, and dendron layers, that is, hydrophilic, solvophobic, and oleophilic layers. In this case, perfluorooctadecanoic acids play a role for ordering of block copolymers. 

The extension of brush molecules is caused by excluded volume repulsion of the 2D-adsorbed side chains. Therefore, the length of adsorbed brushes should also depend on the grafting density. Copolymer brushes with a random sequence of methyl methacrylate and poly(n-butyl acrylate)-substituted methacrylate units were prepared with different compositions, i.e., grafting densities. Table 3 com-... 

Polyolefin, PO [of ethylene, propylene, butylene, 4-methylpentene, and their copolymers with 1-aUcenes, vinyls, (meth)acrylates - preferably PP], was grafted at a ratio 1 9-4 1 with 1-20 wt% of (meth)acrylic acid and >30 wt% of styrene and/or aUcyl- and/or halo-substituted styrene, methacrylic ester, and 0-60 % of other comonomers [e.g., vinyl aromatic, ester], at least some of the acid units of methacrylic acid and/or acrylic acid bearing a charge and being associated with non-polymeric counterions [e.g., 90 % methyl methacrylate, 5 % butyl acrylate, and 5 % methacrylic acid with either or Mg ". The ionomer could be blended with PO either during or after manufacturing. 

Y., and Okamoto, Y. (2011) Synthesis and characterization of trifluoromethyl substituted styrene polymers and copolymers with methacrylates effects of trifluoromethyl substituent on styrene. Polymer, 52 (4), 949 —953. 

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