Molecular weight effects on the liquid-crystalline properties of poly(vinyl ether)s with pendant cyanobiphenyl mesogenic groups

Sagane, Toshihiro; Lenz, Robert W.

doi:10.1021/ma00199a044

Cited by 51 publications

(30 citation statements)

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“…This mesophase exhibits a classic focal conic fan-shaped texture. Poly(6-10) presents a mesomorphic behavior which resembles that of poly (6-1 1).l1 The first and second DSC heating scans of poly (6)(7)(8)(9)(10) are different and, therefore, both are shown in Figure 4a,b. Since poly (6)(7)(8)(9) with a degree of polymerization of about three shows only an enantiotropic SA phase, this means that the slope of the T,,,-M, dependence is higher than that of the Tn-i-Mn dependences.…”

Section: Resultsmentioning

confidence: 99%

“…Over the entire range of molecular weights, poly(6-9) displays only an enantiotropic SA mesophase. The DSC traces of poly (6)(7)(8)(9)(10) obtained from the first and second heating and from the first cooling scans are presented in Figure 4. As we have discussed at the beginning of this section, 8-9 displays both nematic and monotropic SA mesophases.…”

Section: Resultsmentioning

confidence: 99%

“…Scheme I Synthesis of 94 (4-Cyano-4'-biphenylyl)oxy]nonyl Vinyl Ether (6-9) and I-[ (4-Cyano-4'-biphenylyl)oxy]heptyl Vinyl Ether (6)(7)(8)(9)(10) and Model Compounds 8-9 and 8-10 4-Phenylphenol(98%), 1,lO-phenanthroline (anhydrous, 99%), palladium(I1) acetate (all from Lancaster Synthesis), ferricchloride anhydrous (98%, Fluka), copper(1) cyanide (99%), 9-borabicyclo[3.3.1]nonane (CBBN, crystalline, 98% ), 9-bromononan-1-01 (97%), lO-bromodecan-l-o1(90%), and the other reagents (all from Aldrich) were used as received.…”

Section: Methodsmentioning

confidence: 99%

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Molecular engineering of liquid crystalline polymers by living polymerization. 10. Influence of molecular weight on the phase transitions of poly{ι-[(4-cyano-4'-biphenylyl)oxy]alkyl vinyl ether}s with nonyl and decanyl alkyl groups

Percéc¹,

Lee²

1991

Macromolecules

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The synthesis and living cationic polymerization of 9-[ (4-cyano-4'-biphenyl)oxy]nonyl vinyl ether (6-9) and 10-[(4-cyano-4'-biphenylyl)oxy]decanyl vinyl ether (6-10) are described. The mesomorphic behavior of poly(6-9) and poly(6-10) with narrow molecular weight distributions and degrees of polymerization from 2 to 32 was discussed by comparison to that of 9-[ (4-cyano-4'-biphenylyl)oxy]nonyl ethyl ether (8-9) and 10-[(4-cyano-4'-biphenylyl)oxy]decanyl ethyl ether @-lo), which are the model compounds of the monomeric structural units of poly(6-9) and poly(6-10). 8-9 exhibits monotropic nematic and monotropic SA, while 8-10 exhibits monotropic smectic A mesophases. Irrespective of the thermal history of the sample, over the entire range of molecular weights, poly(6-9) exhibits an enantiotropic SA mesophase. In the first heating scan, poly(6-10) exhibits a crystalline phase followed by an enantiotropic SA mesophase. In the second heating scan, poly(6-10)s with degrees of polymerization below 16 exhibit an enantiotropicsA mesophase, while polymers with higher degrees of polymerization display both SA and sx (unidentified) enantiotropic mesophases. Finally, the phase behavior of poly(w-[ (4-cyano-4'-biphenylyl)oxy]alkyl vinyl etherjs with alkyl from ethyl to undecanyl will be discussed at four different degrees of polymerization: 30, 23, 13, and 4.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Molecular engineering of liquid crystalline polymers by living polymerization. 10. Influence of molecular weight on the phase transitions of poly{ι-[(4-cyano-4'-biphenylyl)oxy]alkyl vinyl ether}s with nonyl and decanyl alkyl groups

Percéc¹,

Lee²

1991

Macromolecules

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“…It has also been shown that vinyl ethers can be polymerized by a living cationic mechanism, giving well-defined polymers with narrow molecular mass distributions and tailored molecular masses (Refs. [8][9][10][11][12][13][14][15][16][17][18][19][20]. If initiating systems based on ethylaluminumdichloride and dimethylsulfide or triflic acid and dimethylsulfide (Refs.…”

Section: Introductionmentioning

confidence: 99%

Cationic bulk polymerization of vinyl ethers in the liquid crystalline phase

Jonsson

Percéc

Gedde

et al. 1992

Makromolekulare Chemie. Macromolecular Symposia

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Cationic bulk polymerization of liquid crystalline phenyl benzoate and biphenyl vinyl ethers was performed using either thermal or photochemical initiation by onium salts. High molecular mass polymers having narrow molecular mass distribution were produced in high yields at very high temperatures (i.e., ≤ 120°). Seemingly, the polymerization system could stabilize the growing species and thus reduce the amount of chain transfer reactions. Thin films of the monomers were oriented in their liquid crystalline state by the use of conventional ordering techniques used for low molar mass liquid crystals. On subsequent polymerization the orientation was preserved giving liquid crystalline thin films having a very high degree of order.

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“…[1][2][3][4][5][6][7][8][9][10] However, to our knowledge the present series of publications is the first one which attempts to provide a comprehensive study on th4 influence of molecular weight on the mesomorphic transitions of a series of polymers with spacer lengths varying from two to eleven methylenic units, and narrow molecular weight distribution. The polymers investigated by us are obtained through the living cationic polymerization of w-[(4-cyano-4'-biphenyl)oxylalkyl vinyl ethers.…”

Section: Introductionmentioning

confidence: 99%

Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization. 9. Living Cationic Polymerization of 5-((4-Cyano-4'-Biphenyl) oxy)pentyl Vinyl Ethers and 7-((4-Cyano-4'-Biphenyl)oxy)heptyl Vinyl Ether, and the Mesomorphic Behavior of the Resulting Polymers

Percéc¹,

Lee²,

Ackerman³

1990

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Molecular weight effects on the liquid-crystalline properties of poly(vinyl ether)s with pendant cyanobiphenyl mesogenic groups

Cited by 51 publications

References 1 publication

Molecular engineering of liquid crystalline polymers by living polymerization. 10. Influence of molecular weight on the phase transitions of poly{ι-[(4-cyano-4'-biphenylyl)oxy]alkyl vinyl ether}s with nonyl and decanyl alkyl groups

Molecular engineering of liquid crystalline polymers by living polymerization. 10. Influence of molecular weight on the phase transitions of poly{ι-[(4-cyano-4'-biphenylyl)oxy]alkyl vinyl ether}s with nonyl and decanyl alkyl groups

Cationic bulk polymerization of vinyl ethers in the liquid crystalline phase

Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization. 9. Living Cationic Polymerization of 5-((4-Cyano-4'-Biphenyl) oxy)pentyl Vinyl Ethers and 7-((4-Cyano-4'-Biphenyl)oxy)heptyl Vinyl Ether, and the Mesomorphic Behavior of the Resulting Polymers

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