Synthesis of side-chain liquid-crystal line homopolymers and triblock copolymers with p-methoxyazobenzene moieties and poly(ethylene glycol) as coil segments by atom transfer radical polymerization and their thermotropic phase behavior

被引:78
作者
He, XH
Zhang, HL
Yan, DY
Wang, XY
机构
[1] Shanghai Jiao Tong Univ, Coll Chem & Chem Engn, Shanghai 200240, Peoples R China
[2] Xiangtan Univ, Coll Chem, Dept Polymer Sci & Engn, Xiangtan 411105, Peoples R China
关键词
atom transfer radical polymerization (ATRP); triblock copolymer; liquid crystalline copolymers (LCP); block copolymers; poly(ethylene glycol) (PEG); azobenzene;
D O I
10.1002/pola.10870
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
A series of side-chain liquid-crystalline (LC) homopolymers of poly[6-(4-ethoxy-4'-oxy-azobenzene) hexyl methacrylatel with different degrees of polymerization were synthesized by atom transfer radical polymerization (ATRP), which were prepared with a wide range of number-average molecular weights from 5.1 x 10(3) to 20.6 x 10(3) with narrow polydispersities of around 1.17. Thermal investigation showed that the homopolymers exhibit two mesophases, a smectic phase, and a nematic phase, and the phase-transition temperatures of the homopolymers increase clearly with increasing molecular weights. A series of novel LC coil triblock copolymers with narrow polydispersities was synthesized by ATRP, and their thermotropic phase behavior was investigated with differential scanning calorimetry and polarized optical microscopy. The LC coil triblocks were designed to have an LC conformation of poly [6-(4'-methoxy-4'-oxy-azobenzene) hexyl methacrylatel with a wide range of molecular weights from 3.5 x 10(3) to 1.7 x 10(4) and the coil conformation of poly(ethylene glycol) (PEG) (number-average molecular weight: 6000 or 12,000) segment. Their characterization was investigated with H-1 NMR, Fourier transform infrared spectra, and gel permeation chromatography. Triblock copolymers exhibited a crystalline phase, a smectic phase, and a nematic phase. The phase-transition temperatures from the smectic to nematic phase and from the nematic to isotropic phase increased, and the crystallization of PEG depressed with increasing molecular weight of the LC block. (C) 2003 Wiley Periodicals, Inc.
引用
收藏
页码:2854 / 2864
页数:11
相关论文
共 32 条
[1]   PHOTOCHROMIC LIQUID-CRYSTALLINE POLYMERS MAIN CHAIN AND SIDE-CHAIN POLYMERS CONTAINING AZOBENZENE MESOGENS [J].
ANGELONI, AS ;
CARETTI, D ;
CARLINI, C ;
CHIELLINI, E ;
GALLI, G ;
ALTOMARE, A ;
SOLARO, R ;
LAUS, M .
LIQUID CRYSTALS, 1989, 4 (05) :513-527
[2]   Functional polymers by atom transfer radical polymerization [J].
Coessens, V ;
Pintauer, T ;
Matyjaszewski, K .
PROGRESS IN POLYMER SCIENCE, 2001, 26 (03) :337-377
[3]   LIQUID-CRYSTALLINE SIDE-GROUP BLOCK-COPOLYMERS WITH N-BUTYL METHACRYLATE AS AN AMORPHOUS A-BLOCK - SYNTHESIS AND CHARACTERIZATION [J].
FISCHER, H ;
POSER, S ;
ARNOLD, M .
MACROMOLECULES, 1995, 28 (20) :6957-6962
[4]   ON THE INFLUENCE OF THE MORPHOLOGICAL STRUCTURE ON THE LIQUID-CRYSTALLINE BEHAVIOR OF LIQUID-CRYSTALLINE SIDE-CHAIN BLOCK-COPOLYMERS [J].
FISCHER, H ;
POSER, S ;
ARNOLD, M ;
FRANK, W .
MACROMOLECULES, 1994, 27 (24) :7133-7138
[5]   Synthesis and characterization of polystyrene-b-poly(1,2-isoprene-ran-3,4-isoprene) block copolymers with azobenzene side groups [J].
Hayakawa, T ;
Horiuchi, S ;
Shimizu, H ;
Kawazoe, T ;
Ohtsu, M .
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 2002, 40 (14) :2406-2414
[6]   Synthesis of side group liquid crystal-coil triblock copolymers with cyanobiphenyl moieties and PEG as coil segments by atom-transfer radical polymerization and their thermotropic phase behavior [J].
He, XH ;
Zhang, HL ;
Wang, XY .
POLYMER BULLETIN, 2002, 48 (4-5) :337-344
[7]   Synthesis of side chain liquid crystal-coil diblock copolymers with p-methoxyazobenzene side groups by atom-transfer radical polymerization [J].
He, XH ;
Zhang, HL ;
Wang, XY .
POLYMER JOURNAL, 2002, 34 (07) :523-528
[8]   Synthesis of amphiphilic PS-b-PEG-b-PS by atom transfer radical polymerization [J].
Jankova, K ;
Chen, XY ;
Kops, J ;
Batsberg, W .
MACROMOLECULES, 1998, 31 (02) :538-541
[9]  
Klok HA, 2001, ADV MATER, V13, P1217, DOI 10.1002/1521-4095(200108)13:16<1217::AID-ADMA1217>3.0.CO
[10]  
2-D