Anionic polymerizations of 2-methoxyethyl methacrylate (1), 2-(2-methoxyethoxy)ethyl methacrylate (2), and 2-[2-(2-methoxyethoxy)ethoxy]ethyl methacrylate (3) were carried out with 1,1diphenyl-3-methylpentyllithium/lithium chloride and diphenylmethylpotassium/diethylzinc in THF at -78 °C for 2-4 h. The resulting polymers possessed the predicted molecular weights based on the molar ratios between monomers to initiators and the narrow molecular weight distributions (M w/Mn < 1.1). The stability of the propagating chain ends of poly(2) and poly(3) was confirmed by the quantitative efficiency in the reversible sequential block copolymerizations between 2 and 3. New block copolymers having well-defined chain structures, poly(2)-block-poly(3), poly(3)-block-poly(2), polystyrene-block-poly-(1), polystyrene-block-poly(2), and polystyrene-block-poly(3), were anionically synthesized. Both the solubility and the cloud point of polymers strongly depended on the length of hydrophilic oligo(ethylene glycol) unit. Poly(2) and poly(3) with longer oligo(ethylene glycol) chains were readily soluble in water, whereas poly(1) was insoluble in water. The aqueous solutions of poly(2) and poly(3) showed the reversible cloud points at 26 and 52 °C, respectively.

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A series of well-defined amphiphilic block copolymers containing poly[oligo(ethylene glycol) methacrylate] (POEGMA)) segments were synthesized by the sequential anionic copolymerization of styrene and trialkylsilyl-protected oligo(ethylene glycol) methacrylates followed by deprotection. OEGMA monomers possessed terminal OH groups on the pendant side chains and included the esters of ethylene glycol, di(ethylene glycol), and tri(ethylene glycol) to change the polarity of hydrophilic polymethacrylate segments. The corresponding methyl ethers of oligo(ethylene glycol) methacrylates (MOEGMA) were also employed to synthesize the amphiphilic block copolymers of polystyrene (PS) and PMOEGMA. Microphase separated structures of the block copolymers were analyzed by small-angle X-ray scattering (SAXS). The block copolymers containing POEGMA segments displayed strongly segregated lamellar structure with sharp interfaces; however, the PMOEGMA counterparts showed either weakly segregated lamellar or disorder structures. Angle-dependent X-ray photoelectron spectroscopic (XPS) measurement of the films of block copolymers with POEGMA segments revealed that hydrophobic polystyrene segments exclusively covered the outermost surfaces, as expected. By contrast, enrichment of oligo(ethylene glycol) units was unexpectedly observed in the block copolymers of PMOEGMA types. Contact angle measurement also indicated that the film surface was almost completely covered with hydrophilic PMOEGMA segments rather than polystyrene segments. The nature of the terminal moiety on the oligo(ethylene glycol) side chain, OH or OCH3, played a very important role in determining the surface structure of the amphiphilic block copolymer films. The terminal moiety had a dominant influence either on the interaction parameter with PS or on the interaction with the surface, whereas the number of ethylene glycol units primarily determined the solubility of polymethacrylate segments in water.

Vinyl addition copolymerization of norbornene with norbornene derivatives bearing siloxane substituent, three arm-, cyclicand phenyl-siloxane groups, was realized in the presence of the binary Ni(acac) 2 /B(C 6 F 5 ) 3 system. The resulting copolymers show good solubility in common organic solvents and possess a very high grass transition temperature between 265 and 360 C, depending on the content and structure of the siloxane groups. The incorporation of siloxane groups linked to the polymer chain results in a significant increase in the mechanical flexibility of the corresponding films. Furthermore, the gas permeability is also dependent on the content and structure of the siloxane groups, and the films obtained for the polymers with three arm-siloxane group (-Si(OSiMe 3 ) 3 ) display high oxygen permeability in the range of 39 to 239 Barrer.KEY WORDS: Polynorbornene / Siloxane Substituent / Copolymerization / Nickel Catalyst / Norbornene can be polymerized by three different methods: ring opening metathesis polymerization (ROMP), cationic or radical polymerization, and vinyl addition polymerization. 1Among these polymers, addition-type poly(norbornene), presenting the rigid bicyclic structure, is recently attracting strong interest in optical and opto-electronic device applications because of high optical transparency, low birefringence, very high glass transition temperature and low dielectric constant. However, poor solubility in common organic solvents and mechanical brittleness are serious disadvantages for the processing of the polymer materials. These problems can be improved markedly by copolymerizing a small amount of functional norbornene derivatives.So far, many types of poly(norbornene)s with functional groups have been prepared. [2][3][4][5][6][7][8][9][10][11][12][13] Heitz et al. 2,3 investigated the addition-type copolymerizations of norbornene with norbornene carboxylic acid esters, and found that the solubility of the copolymers and the thermal properties, such as glasstransition and decomposition temperatures, were dependent on the content as well as structure of the substituents. Risse et al. [4][5][6] came to the same conclusion by studying poly-(norbornene)s containing hydroxyl, carboxylic acid and ester. Goodall et al.7-9 and Grove et al. 10 prepared alkyl-or alkoxysilyl-substituted poly(norbornene)s, which showed improved mechanical toughness and adhesion to common substrate materials. On the other hand, Dorkenoo et al. 11and Finkelshtein et al.12 investigated the homopolymers of norbornene derivatives bearing alkyl or alkylsilyl substituents, and demonstrated that the chain length and the bulkiness of the substituents played a decisive role in the transport properties, such as gas permeability and permselectivity, for the polymeric membranes. These results show that the nature of substituent and the content in the main chain are an important factor for the regulation of the material properties.Poly(siloxane) is a class of polymers that has practical importance in the consumer and indus...

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