Side‐chain liquid‐crystalline polymers based on flexible rod‐like mesogen directly attached to backbone

In this article, we report the synthesis and characterization of a new end-on side-chain liquid crystalline polymer (SCLCP), poly[4-(4′-alkoxyphenyloxymethylene)styrene] [denoted as Poly(n-POMS), where n is the carbon number of the alkyl tail, n = 2, 4, 6, 8, 12, 16], with the flexible rod-like mesogenic side-chain directly attached to the polymer backbone without flexible spacer. The polymer was obtained by using free radical polymerization. The chemical structures of Poly(n-POMS) and the corresponding monomer were characterized using various techniques with satisfactory analysis data. A combination analysis of differential scanning calorimetry, polarized light microscopy, small angle X-ray scattering, and wide-angle X-ray diffraction has been conducted to investigate the phase behavior of Poly(n-POMS). Poly(2-POMS), Poly(4-POMS), and Poly(6-POMS) are amorphous. Poly(8-POMS) develops partially into the liquid crystal phase, and Poly(12-POMS) and Poly(16-POMS) self-assembly into the smectic A (SmA) phase. Upon increasing temperature, the phase transition of Poly(16-POMS) follows the sequence of SmA1 ↔ SmA2 ↔ isotropic (I), which may be attributed to the conformation isomerization of the flexible rod-like mesogens. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

[1]  Xing Fan,et al.  Mesogen-jacketed liquid crystalline polymers. , 2010, Chemical Society reviews.

[2]  M. R. Imam,et al.  Dendron-mediated self-assembly, disassembly, and self-organization of complex systems. , 2009, Chemical reviews.

[3]  V. Percec,et al.  Induced helical backbone conformations of self-organizable dendronized polymers. , 2008, Accounts of chemical research.

[4]  C. Chai,et al.  Synthesis and Phase Structures of Mesogen-Jacketed Liquid Crystalline Polymers Containing 1,3,4-Oxadiazole Based Side Chains , 2007 .

[5]  Xiaofang Chen,et al.  Synthesis and properties of mesogen-jacketed liquid crystalline polymers with asymmetry mesogenic core , 2007 .

[6]  Stephen Z. D. Cheng,et al.  Molecular Weight Dependence of Phase Structures and Transitions of Mesogen-Jacketed Liquid Crystalline Polymers Based on 2-Vinylterephthalic Acids , 2004 .

[7]  X. Wan,et al.  Synthesis and Characterization of A New Series of “Mesogen-Jacketed Liquid Crystal Polymers” Based on the Newly Synthesized Vinylterephthalic Acid , 1999 .

[8]  V. Percec Molecular design of novel liquid crystalline polymers with complex architecture: Macrocyclics and dendrimers , 1995 .

[9]  V. Percec,et al.  Molecular-Recognition-Directed Self-Assembly of Supramolecular Polymers , 1994 .

[10]  M. Kawasumi,et al.  Molecular Recognition Directed Self-Assembly of Supramolecular Architectures , 1994 .

[11]  V. Percec,et al.  Molecular engineering of side‐chain liquid‐crystalline polymers by living cationic polymerization , 1992 .

[12]  V. Percec,et al.  Liquid-crystalline polyethers based on conformational isomerism. 18. Polyethers based on a combined mesogenic unit containing rigid and flexible groups: 1-(4-hydroxy-4'-biphenyl)-2-(4-hydroxyphenyl)butane , 1991 .

[13]  V. Percec,et al.  Liquid crystalline polyethers based on conformational isomerism , 1991 .

[14]  V. Percec,et al.  Simulataneous x-ray/DSC study of mesomorphism in polymers with a semiflexible mesogen , 1990 .

[15]  V. Percec,et al.  Liquid-crystalline polyethers based on conformational isomerism. 10. Synthesis and determination of the virtual mesophases of polyethers based on 1-(4-hydroxyphenyl)-2-(2-methyl-4-hydroxyphenyl)ethane and .alpha.,.omega.-dibromoalkanes containing from 17 to 20 methylene units , 1990 .

[16]  C. Mcardle,et al.  Side Chain Liquid Crystal Polymers , 1990 .

[17]  V. Percec,et al.  Liquid crystalline polyethers and copolyethers based on conformational isomerism. 3. The influence of thermal history on the phase transitions of the thermotropic polyethers and copolyethers based on 1-(4-hydroxyphenyl)-2-(2-methyl-4-hydroxyphenyl)ethane and flexible spacers containing an odd number , 1989 .

[18]  V. Percec,et al.  Liquid crystalline polyethers based on conformational isomerism. II: Thermotropic polyethers and copolyethers based on 1-(4-hydroxyphenyl)-2-(2-methyl-4-hydroxyphenyl)ethane and flexible spacers containing an odd number of methylene units , 1989 .

[19]  V. Percec,et al.  Synthesis and characterization of liquid crystalline polyacrylates and polymethacrylates containing benzyl ether and diphenyl ethane based mesogens , 1989 .

[20]  V. Percec,et al.  Liquid crystalline polyethers based on conformational isomerism. 1. Quasi-rigid polyethers containing methyleneoxy units , 1988 .

[21]  V. Percec,et al.  Liquid-crystalline polymers containing heterocycloalkane mesogenic groups. 5. Synthesis of biphasic chiral smectic polysiloxanes containing 2,5-disubstituted-1,3-dioxane- and 2,5-disubstituted-1,3,2-dioxaborinane-based mesogenic groups , 1987 .

[22]  V. Percec,et al.  Synthesis and characterization of liquid crystalline polysiloxanes containing benzyl ether mesogens , 1987 .

[23]  V. Percec,et al.  Synthesis and characterization of liquid crystalline poly(p-vinylbenzyl ether)s , 1987 .

[24]  V. Percec,et al.  Liquid crystalline copolymers of monomer-pairs containing mesogenic units which exhibit constitutional isomerism , 1987 .

[25]  V. Percec,et al.  Towards tobacco mosaic virus‐like self‐assembled supramolecular architectures , 1994 .

[26]  V. Percec,et al.  Poly{2-vinyloxyethyl 3,4,5-tris[4-(n-dodecanyloxy)benzyloxy]benzoate}: a self-assembled supramolecular polymer similar to tobacco mosaic virus , 1992 .

[27]  V. Percec,et al.  Liquid crystalline polyethers based on conformational isomerism. 6. Influence of copolymer composition of a ternary copolyether based on 1-(4-hydroxyphenyl)-2-(2-methyl-4-hydroxyphenyl)ethane, 1,5-dibromopentane, 1,7-dibromoheptane, and 1,9-dibromononane on its mesomorphic phase transitions , 1990 .

[28]  V. Percec,et al.  Liquid‐crystalline polyethers and copolyethers based on conformational isomerism, 5. Thermotropic copolyethers based on 1‐(4‐hydroxyphenyl)‐2‐(2‐methyl‐4‐hydroxyphenyl)ethane and flexible spacers containing odd and even numbers of methylene units , 1990 .

[29]  Z. Wen,et al.  Liquid-crystalline side-chain polymers without flexible spacer , 1989 .

[30]  Qifeng Zhou,et al.  Synthesis of liquid-crystalline polyacrylates with laterally substituted mesogens , 1987 .

[31]  V. Percec,et al.  Liquid crystalline polymers containing heterocycloalkane mesogens , 1987 .

[32]  H. Ringsdorf,et al.  Model considerations and examples of enantiotropic liquid crystalline polymers. Polyreactions in ordered systems, 14 , 1978 .