E. V. Belyaeva

Hydrodynamic, conformational, and electrooptical properties of cylindrical dendrimers with dendron ionic addition in solutions

Cylindrical dendrimers of first, second, and third generations with side dendrons based on L-aspartic acid which are attached to poly(styrenesulfonic acid) chains via ionic bonds are studied by molecular hydrodynamic, optical, and electrooptical measurements. Macromolecules of the said dendrimers demonstrate significant kinetic rigidity in external electric and hydrodynamic fields simultaneously with moderate equilibrium chain rigidity. The comparative analysis of the experimental data on various cylindrical dendrimers with the polyvinyl backbone and L-aspartic acid-based dendrons is performed. It has been shown that, in solvents not disturbing intramolecular hydrogen bonds between side dendrons, the conformational and dynamic properties of various cylindrical dendrimers are similar. The molecular characteristics of cylindrical dendrimers in non-dissociating solvents are insignificantly affected by the mode of dendron attachment to the backbone (covalent or ionic binding).

Hydrodynamic, dynamo-optical and conformational characteristics of molecules of phenyl-substituted para-aromatic polyesters

Abstract Hydrodynamic, optical and conformational properties of mono-phenyl-substituted para -aromatic polyester (PAPE) in tetrachloroethane and dichloroacetic acid have been studied by sedimentation-diffusion analysis, viscometry and flow birefringence. The effect of phenyl side-groups on the equilibrium rigidity of PAPE chains was analysed. On the basis of these data, the energies of hindrance to intramolecular rotations about the ester bonds of various phenyl-substituted PAPEs were estimated.

Hydrodynamic, optical and conformational properties of molecules of aromatic polyesters containing 3,3′-biphenylene fragments in the main chains

Abstract The hydrodynamic, optical and conformational properties of molecules of fractions of two aromatic polyesters (APE) containing 3,3′-biphenylene fragments in their chains have been investigated by sedimentation-diffusion analysis and flow birefringence in dilute solutions. The experimental data on the translational mobility and dynamo-optical characteristics of molecules of these polymers are compared with those for previously investigated APE with similar structures but containing no biphenylene fragments. As a result of this analysis, the geometric parameters of the repeating chain unit were characterized, and the equilibrium rigidities of the molecule of the APE were estimated. It was shown that the flexibility of these molecules is determined by the character of intramolecular rotation about the biphenylene bond and that this rotation is virtually unhindered.

Dynamooptical and electrooptical properties of poly(methylphenylsiloxane) in solution and bulk

The dynamooptical, electrooptical, and hydrodynamic properties of a low-molecular-mass poly(methylphenylsiloxane) containing 33% phenyl radicals (with respect to the total amount of side groups) in dilute solutions and in bulk are studied. The size of macromolecules, as well as the molecular mass of the polymer, its shear optical coefficients Δn/Δτ = (0.29 ± 0.3) × 10−10 (in decalin) and (0.43 ± 0.03) × 10−10 cm s2/g (in bulk), and the specific Kerr constants K = (2.30 ± 0.02) × 10−12 (in benzene), (2.23 ± 0.02) × 10−12 (in decalin), and (2.24 ± 0.09) × 10−12 cm5/[g (300 V)2] (in bulk), are estimated and compared with the corresponding characteristics of poly(dimethylsiloxane). The effect of solvents on the intramolecular mobility, optical anisotropy, and dipole structure of polymer macromolecules is considered.

Hydrodynamic and Conformational Properties of Aromatic Polyesters Containing Flexible Polyoxyethylene Fragments

Abstract Conformational properties of molecules of the thermotropic aromatic polyesters containing mesogenic and flexible very long oxyethylene fragments are discussed on the basis of molecular hydrodynamic investigations. Changes in Conformational properties and equilibrium flexibility of molecules, caused by changes in the way of biphenylene fragments insertion into the chain are analyzed. Intramolecular orientational mobility of mesogenic fragments is characterized by a dimentionless parameter δ/A.