Electrical birefringence in solutions of rigid-chain polymers

Tsvetkov, V.N.; Цветков, Н. В.

doi:10.1070/rc1993v062n09abeh000050

Cited by 25 publications

(40 citation statements)

References 41 publications

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“…Similar significant differences in electro‐optical characteristics of polymers in polar and non‐polar solvents have been observed before . These differences are caused by orientational correlation of polar solvent molecules with respect to a macromolecule; the latter acquires a dipole moment, which manifests itself as a permanent dipole in electro‐optical experiments.…”

Section: Resultssupporting

confidence: 71%

“…Consistency and inner correlation of the obtained hydrodynamic data should be checked by calculation of the hydrodynamic invariant:

A_{0} = {(R {([], D)}^{2} [s] [η])}^{1 true/ 3}

…”

Section: Resultsmentioning

confidence: 99%

“…The Kerr constant is related to the molecular mass and dipole structure of molecules or particles which become oriented in an electrical field through the following equation:

K = \frac{2 π N_{A}}{135 k T} \frac{{((), n^{2} + 2)}^{2}}{n} \frac{{((), ϵ + 2)}^{2}}{9} \frac{γ_{1} - γ_{2}}{M} ([], \frac{μ^{2}}{k T} \frac{3 \cos^{2} θ - 1}{2} + ((), δ_{1} - δ_{2}))

…”

Section: Resultsmentioning

confidence: 99%

“…FB is caused by the anisotropy of polarizability of macromolecules and their shape:

\frac{Δ n}{Δ τ} = \frac{4 π}{45 k T} \frac{{((), n^{2} + 2)}^{2}}{n} ((), γ_{1} - γ_{2}) \frac{b_{0}}{6 F ((), p)}

…”

Section: Resultsmentioning

confidence: 99%

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Conformational and hydrodynamic parameters of hyperbranched pyridylphenylene polymers

Цветков

Gubarev

Lebedeva

et al. 2016

Polymer International

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Hydrodynamic and optical methods were applied to study conformational and physical properties of hyperbranched pyridylphenylene polymers in dilute solutions. The samples were synthesized using Diels–Alder polycyclocondensation. It was demonstrated that hydrodynamic properties of the studied macromolecules were typical for compact non‐percolated spheres. Optical and electro‐optical methods revealed information regarding the shape and asymmetry of the macromolecules (p ≈ 1.4). The contributions of optical shape effect to the observed flow birefringence of polypyridylphenylene solutions and intrinsic anisotropy of polarizability were evaluated and analysed. It was shown that varying the polymer composition (i.e. the degree of branching) caused considerable changes in the anisotropy of optical polarizability of the polymers. Dramatic difference of the electro‐optical properties in non‐polar (toluene) and polar (tetrachloroethane) solvents was found; this difference was related to the orientational correlation of polar solvent molecules with respect to the macromolecules. Dynamic properties were studied by non‐equilibrium electric birefringence which had a reasonable agreement with the dimensions estimated from hydrodynamic data. © 2016 Society of Chemical Industry

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Section: Resultssupporting

confidence: 71%

“…Consistency and inner correlation of the obtained hydrodynamic data should be checked by calculation of the hydrodynamic invariant:

A_{0} = {(R {([], D)}^{2} [s] [η])}^{1 true/ 3}

…”

Section: Resultsmentioning

confidence: 99%

“…The Kerr constant is related to the molecular mass and dipole structure of molecules or particles which become oriented in an electrical field through the following equation:

K = \frac{2 π N_{A}}{135 k T} \frac{{((), n^{2} + 2)}^{2}}{n} \frac{{((), ϵ + 2)}^{2}}{9} \frac{γ_{1} - γ_{2}}{M} ([], \frac{μ^{2}}{k T} \frac{3 \cos^{2} θ - 1}{2} + ((), δ_{1} - δ_{2}))

…”

Section: Resultsmentioning

confidence: 99%

“…FB is caused by the anisotropy of polarizability of macromolecules and their shape:

\frac{Δ n}{Δ τ} = \frac{4 π}{45 k T} \frac{{((), n^{2} + 2)}^{2}}{n} ((), γ_{1} - γ_{2}) \frac{b_{0}}{6 F ((), p)}

…”

Section: Resultsmentioning

confidence: 99%

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Conformational and hydrodynamic parameters of hyperbranched pyridylphenylene polymers

Цветков

Gubarev

Lebedeva

et al. 2016

Polymer International

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“…Appreciably lower rigidity of CTD macromolecules in TCE, compared to CF, is due to the fact that the rigidity of molecular chains of cellulose esters is largely determined by intramolecular hydrogen bonds which can be weakened under the action of a polar solvent capable of breaking these bonds. This feature is manifested not only in hydrodynamic properties of cellulose derivatives, but also, no less clearly, in FBR [5,9,10]. In accordance with the lower equilibrium rigidity of CTD in TCE, the intramolecular rotation hindrance factor in this solvent is also lower: σ = 4.28.…”

Section: Methodsmentioning

confidence: 64%

Hydrodynamic, conformational, and optical properties of cellulose tridecanoate molecules in solutions

et al. 2012

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Cellulose tridecanoates of various molecular weights were synthesized, and their characteristics in chloroform and tetrachloroethane solutions were studied by methods of translational diffusion, velocity sedimentation, fl ow birefringence (Maxwell's method), and viscometry. The effects of solvent and temperature on the conformational characteristics of the macromolecules under consideration were examined. The anisotropy of the monomeric unit of cellulose tridecanoates was studied, and the contribution of pendant chains to the optical anisotropy of macromolecules of cellulose esters with aliphatic substituents was analyzed.Amphiphilic properties of aliphatically substituted cellulose in combination with high equilibrium rigidity of the molecules make it an attractive object for preparing mono-and multilayer LangmuirBlodgett nanofi lms. Successful use of such fi lms in micro-and nanoelectronics, analytical biotechnology, bioelectronics, and membrane technologies stimulates interest in studying the structure and conformational properties of the molecules of the starting compounds [1][2][3][4].In this work, we studied cellulose tridecanoate [CTD, pendant group CH 3 -(CH 2 ) 11 -CO-] by methods of molecular hydrodynamics and optics. We examined nine samples differing in the origin of the base (bacterial, wood, cotton, linter, microcrystalline cellulose) in chloroform (CF) and tetrachloroethane (TCE). The mean degree of substitution DS was 210. EXPERIMENTALThe intrinsic viscosity [η] was measured with an Ostwald capillary viscometer following the standard procedure [5]. In the measurements in CF, the temperature was varied in the interval 21-51°С. The diffusion coeffi cients D were measured with a polarization diffusometer [5] in a glass cell 3 cm long (along the beam) at 24°С. The solution concentration c did not exceed 0.1 × 10 -2 g cm -3 , which corresponded to practically limiting dilution. The fl otation coeffi cients -s 0 of CTD samples in chloroform (24°С) were determined with an analytical ultracentrifuge (МОМ, model 3180/В, Hungary) equipped with a polarization-interferometric attachment [5]. We used a layering two-sector cell with a polyamide insert. The rotor rotation rate was 40 × 10 3 rpm. The coeffi cients -s were extrapolated to zero concentration. The concentration was varied from 0.12 to 0.5 × 10 -2 g cm -3 . The molecular weights of the samples were determined from the measured diffusion (D) and fl otation (-s 0 ) coeffi cients by Svedberg's formula М sD = RТ(s 0 /D)(v -ρ 0 -1) -1 . The partial specifi c volume of the polymer is v -= 1.012 cm 3 g -1 . The refractive indices of the solutions and solvents were determined with a Mettler Toledo refractometer (model RM40, Switzerland) with an accuracy of 10 -4 ± 5 × 10 -5 .The intrinsic viscosities [η] (dl g -1 ) at 21°С, diffusion (D) and fl otation (-s 0 ) coeffi cients at 24°C, temperature

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