The Preparation and Investigation of Macromolecular Architectures for Microlithography by "Living" Free Radical Polymerization

Gradient copolymers by atom transfer radical copolymerization

“…The use of nitroxide mediated polymerization has been shown to be effective for the synthesis of not only homopolymers and block copolymers, but also random and statistical copolymers of styrene. Examples of copolymerization of styrene with comonomers such as 4-hydroxystyrene, 45 4-acetoxystyrene, 45 n-butyl acrylate, 48 butadiene, 47 methyl methacrylate, 49 chloromethylstyrene, 50 acrylonitrile, 22 2-hydroxyethyl methacrylate, 49 4-(hydroxymethyl)styrene, 49 vinylpyrrolidone 49 and maleic anhydride 46 have recently been reported. These reports indicate that copolymers of these comonomers with styrene can be formed using a nitroxide-mediated CRP.…”

Hydrolysis of 4-acetoxystyrene polymers prepared by atom transfer radical polymerization

“…[1][2][3][4][5][6][7][8][9][10][11][12] The synthetic methods include free radical, cationic, and anionic processes. However, in order to avoid side reactions involving the phenolic hydroxyl groups during polymerization, 13 monomers with protecting groups such as acetyl, 1,3,4,11,12,14 -17 alkyl, 4,18 t-butoxycarbonyl, 4 and trialkylsilyl 9,10,19,20 are commonly used for this reaction, followed by deprotection of the functional groups.…”

“…1 However, it should be noted that the parent polymers, due to their preparation by conventional free radical or cationic polymerization, had broad polydispersities. Recently, G. G. Barclay and coworkers 11,12 have prepared poly(4-hydroxystyrene) (PHS) and poly(4-hydroxystyrene-co-styrene) (PHS-co-PS) with narrow molecular weight distribution (MWD) by "living" free radical polymerization. The resulting materials have been characterized by IR, [1][2][3]11,13,14,[21][22][23][24] NMR and GPC, 11,12,14,23 UV 11,13 elemental analysis, 2 or TGA and DSC.…”

“…11 It was also reported that diblock copolymer poly(4-acetoxystyrene-bstyrene) (PAS-b-PS) could be converted to the corresponding amphiphilic material poly(4-hydroxystyrene-b-styrene) (PHS-b-PS) by using a base-catalyzed hydrolysis; however, neither was detailed information given, 15 nor monomodal GPC curve presented. 12 In the last few years, atom transfer radical polymerization (ATRP) 25,26 was developed which opens the door to preparing block copolymers with very unique architectures. We have studied the homopolymerization of 4-acetoxystyrene by ATRP 27 and found that PAS with predetermined molecular weight and narrow MWD could be obtained, and a kinetic study indicated the absence of termination and transfer reactions.…”

Síntese de copolímeros em bloco de p-acetoxiestireno com isopreno através de polimerização "viva" via radical livre

“…Os monômeros de estireno substituído são muito interessantes devido à possibilidade de preparação de polímeros com propriedades fotofísicas e fotoquí-micas [7][8] . O controle da copolimerização de p-acetoxiestireno que resulta na formação de copolímeros em bloco permanece relativamente inexplorada.…”