Solution behavior of two liquid crystalline polymers of different architectures

Richtering, Walter; Schätzle, Joachim; Adams, J.LaMonte; Burchard, Walther

doi:10.1007/bf01410432

Cited by 12 publications

(10 citation statements)

References 22 publications

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“…Similarly, poly[(4‘-methoxyphenyl-4‘ ‘-phenoxy)oligooxyethylene methacrylate]s 6 with zero or one oxyethylene units in the spacer aggregate in THF and CHCl 3 at the concentrations used for GPC measurements (∼0.5 g/L), whereas poly[4‘-(4‘ ‘- n -dodecyloxyphenoxycarbonyl)phenoxy methacrylate] 10 aggregates in CHCl 3 only at concentrations greater than 200 g/L. Poly{6-[4‘-(4‘ ‘-methoxyphenoxycarbonyl)phenoxy])hexyl methacrylate} tends to aggregate more in CHCl 3 8 than in THF. ,, …”

Section: Resultsmentioning

confidence: 99%

“…Many of these SCLCPs aggregate in organic solvents, − evidently due to strong mesogen−mesogen interactions. The formation of an excimer by poly[3-(4‘-cyanophenyl-4‘ ‘-phenoxy)propyl acrylate] in THF at dilute concentrations, but not by 3-(4‘-cyanophenyl-4‘ ‘-phenoxy)pentane, indicates that (intramolecular) mesogen−mesogen interactions are stronger in SCLCPs than in the corresponding low molar mass liquid crystals .…”

Section: Introductionmentioning

confidence: 99%

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Solution Behavior of Topological Isomers of Poly[11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate]s Prepared by Atom Transfer and Conventional Radical Polymerizations

Kasko

Pugh

2004

Macromolecules

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The solution behavior of linear, three-arm star, and comb poly[11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate]s previously synthesized by atom transfer radical polymerization was investigated by gel permeation chromatography (GPCPSt) and light scattering measurements in CH2Cl2, THF, and CHCl3 in order to correlate their size and shape with their molecular architecture and in order to investigate the extent of branching in the corresponding polymer prepared by conventional radical polymerization. The inaccuracy of the GPCPSt molecular weights increases as the polymers become more branched: linear < three-arm star < comb; the discrepancy between the GPCPSt and absolute molecular weights of polymers fractionated from the conventional radical polymerization is between those of the three-arm star and comb polymers in all three solvents. Light scattering studies demonstrate that CH2Cl2 is the best solvent for all of the polymers, resulting in either no aggregation or an insignificant amount of aggregation, whereas all of the topologies except the comb polymers tend to aggregate in THF and CHCl3; nevertheless, the extent of aggregation is not great enough to be detected by variations in the average GPCLS-determined molecular weights measured in any of these solvents. The tendency to aggregate in all of the solvents and the radius of gyration in CH2Cl2 decrease as the branching increases: linear > three-arm star > comb, with the polymer prepared by conventional radical polymerization being similar to the branched polymers. The scaling coefficients (R g = KM ν) of all of the polymers are similar in CH2Cl2, with ν = 0.37 for the three-arm star polymers, ν = 0.39 for the comb polymers, and ν = 0.32 for the polymer prepared by conventional radical polymerization. The relative values of the contraction factors, g = 〈R g 2〉br/〈R g 2〉lin, decrease in the order g star > g comb > g radical for the three-arm star polymers, the comb polymers, and the polymer prepared by conventional radical polymerization, respectively, in CH2Cl2.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Solution Behavior of Topological Isomers of Poly[11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate]s Prepared by Atom Transfer and Conventional Radical Polymerizations

Kasko

Pugh

2004

Macromolecules

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“…The weight averaged molecular weight w M , radius of gyration R g , and second virial coefficient A 2 of the polymers in different solvents could be extracted from the intercept and the corresponding initial slopes 14,15 . The intensity time correlation functions obtained by PCS, which can be related to the relaxation rate Γ, were analyzed by the method of cumulants 11 .…”

Section: Light Scatteringmentioning

confidence: 99%

“…An extrapolation of D app to zero angle gives the translational diffusion coefficient D c at concentration c. D c was then extrapolated linearly to c=0 according to the equation (1) 14,15 .…”

Section: Light Scatteringmentioning

confidence: 99%

Chiral liquid-crystalline polyacrylates from (S)-(-)-2-methyl-1-butanol. Synthesis, mesomorphic properties and light scattering

Merlo

Ritter

Pereira

et al. 2001

J. Braz. Chem. Soc.

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A síntese e o comportamento mesomórfico de dois poliacrilatos quirais líquido cristalinos com cadeia lateral derivados do (S)-(-)-2-metil-1-butanol são descritos. Estes novos poliacrilatos quirais mostram dependência das temperaturas de transição de fase com a massa molar e o comprimento do espaçador. O poliacrilato contendo quatro unidades metilênicas no espaçador mostra fase nemática quiral, enquanto que o poliacrilato com espaçador contendo onze unidades metilênicas mostra fase esmética. Além disto, a fase nemática quiral foi encontrada para massa molar menor e fase esmética para massa molar maior. Experimentos de espalhamento de luz foram realizados em soluções diluídas do poliacrilato contendo onze unidades metilênicas em tetrahidrofurano e diclorometano. Valores de massa molar ponderal média, raio de giro e o segundo coeficiente virial foram determinados através de espalhamento de luz estático, enquanto que o coeficiente de difusão e o raio hidrodinâmico foram obtidos por espectroscopia de correlação de fótons. Uma comparação entre as técnicas indica que o comportamento da cadeia é típico de cadeia linear polidispersa em bom solvente.The synthesis and mesomorphic behavior of two chiral side chain liquid crystalline polyacrylates from (S)-(-)-2-methyl-1-butanol are described. These new polyacrylates show a dependence of the phase transition temperatures on both, molecular weight and spacer length. The polyacrylate with four methylene units in the spacer exhibits a chiral nematic phase whereas the polyacrylate with a spacer containing eleven methylene units presents a smectic phase. In addition, the chiral nematic phase appears for low molecular weight and smectic phase for high molecular weight polyacrylates. Light scattering experiments were performed in dilute solutions of the polyacrylate containing eleven methylene units in tetrahydrofuran and dichloromethane. Values for weight averaged molecular weight, radius of gyration and second virial coefficient were determined by static light scattering whereas the diffusion coefficient and the hydrodynamic radius of the chains were obtained by photon correlation spectroscopy. A comparison between both techniques indicates that the chain behavior can be taken as typical for a polydisperse linear chain in a good solvent.

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“…In this study, hydrodynamic, dynamooptic, and electrooptic investigations are made on a polymer, PMA, with symmetric three-ring mesogenic groups attached to the polymer backbone by its central ring via aliphatic spacer -(CHhhi-(side-on polymer as designated in ref 7). This lateral type of the attachment of a mesogen is a fundamental difference between the structure of the PMA molecule and that of other comb-shaped liquid-crystalline end-on polymers investigated earlier.…”

Section: Introductionmentioning

confidence: 99%

Optical anisotropy and conformation of macromolecules with laterally attached mesogenic side groups

Lavrenko¹,

Kolomietz²,

Finkelmann³

1993

Macromolecules

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Solution behavior of two liquid crystalline polymers of different architectures

Cited by 12 publications

References 22 publications

Solution Behavior of Topological Isomers of Poly[11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate]s Prepared by Atom Transfer and Conventional Radical Polymerizations

Solution Behavior of Topological Isomers of Poly[11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate]s Prepared by Atom Transfer and Conventional Radical Polymerizations

Chiral liquid-crystalline polyacrylates from (S)-(-)-2-methyl-1-butanol. Synthesis, mesomorphic properties and light scattering

Optical anisotropy and conformation of macromolecules with laterally attached mesogenic side groups

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