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The amphiphilic copolymers of N-methyl-N-vinylacetamide and alkylated N-methyl-N-vinylamine combining a hydrophilic backbone and hydrophobic side chains of various lengths and carrying a charge are studied. The results are compared, and the features of the application of known methods for determining the intrinsic viscosity in aqueous and organic solvents are considered. Conclusions are drawn about the intramolecular organization in the molecular chains of the studied copolymers and the manifestation of hydrophobic interactions in macromolecules with different lengths of alkyl radicals. The conditions under which the amphiphilic character of copolymers does not manifest itself are revealed. It is proposed to consider the sign and magnitude of the second derivative of the dependence ln ηr = f(c[η]) as a measure of the hydrophobicity of copolymer chains.

100 years after the birth of polymer science, it can be stated that viscometry of dilute polymer solutions is the most popular method among molecular hydrodynamics methods, the purpose of which is to obtain the molecular characteristics of individual polymer chains. The viscous flow of dilute aqueous solutions of polyelectrolytes–statistical copolymers of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride was investigated in the range of ionic strengths from the minimum (10–6 M) to the maximum possible 6 M NaCl. Intrinsic viscosities were determined as ∂lnηr/∂c at c → 0. The obtained generalized dependence of the intrinsic viscosity on the ionic strength of the solution in a double logarithmic scale is sigmoidal. The intrinsic viscosity values change insignificantly in the range 10–6–10–4 M. The nature of the change in the hydrodynamic volume of charged macromolecules in the entire range of ionic strengths of solutions is discussed in comparison with the theory of single polyelectrolyte macromolecule in the salt solution developed by Vasilevskaya et al., [26].

Molecular hydrodynamics methods (translational diffusion, velocity sedimentation, viscometry) have been used to study copolymers of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride with an average content of charged groups (4.4 ± 0.2) mol % in aqueous 0.2 M NaCl solution. Kuhn–Mark–Houwink–Sakurada scaling relationships have been obtained. Viscous flow has been studied in the widest possible range of ionic strengths of aqueous solutions, from salt-free to 6 M NaCl. The data have been compared with those previously obtained for neutral poly-N-methyl-N-vinylacetamide. It has been shown experimentally for the first time that the character of the dependence of the intrinsic viscosity on the molecular mass of a copolymer of such a composition in solutions of minimal ionic strength is typical of the chains exhibiting intrachain volume effects, i.e. electrostatic long-range interactions.

A series of copolymers of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride with an average content of charged groups of (4.4 ± 0.2) mol % and molecular mass in the range of 22 < M × 10–3, g/mol < 630 are synthesized and characterized. Fractions are studied by sedimentation-diffusion methods in 0.2 mol/L NaCl under almost suppressed polyelectrolyte effects. In salt-free aqueous solutions, their viscous flow is investigated and intrinsic viscosity is determined as [η] ≡ lim(∂lnηr/∂c) at c → 0. The results are compared with the previous data obtained for the copolymer containing (15.7 ± 0.5) mol % of charged groups and the homopolymer. It is shown that the type of intrinsic viscosity dependence on the molecular mass of the copolymer containing 4.4 mol % of charged groups is typical of chains manifesting intrachain volume interactions, while at a 15.7 mol % content of charged groups the type of the dependence is characteristic of chains demonstrating intrachain short-range effects; hence, the chains behave as rigid-chain, permeable. The statistical segment lengths of copolymer macromolecules in salt-free solutions and in 0.2 mol/L NaCl are determined. The data are analyzed in terms of the normalized Kuhn–Mark–Houwink–Sakurada relation.

A complex study of the properties of poly-N-vinylsuccinimides synthesized by the reversible addition-fragmentation chain transfer polymerization (RAFT) was carried out by the methods of molecular hydrodynamics. Molecular masses were determined from the sedimentation-diffusion analysis, the range was 5000

The chapter exemplifies the in-depth analytical characterization of variously structured synthetic and bio-macromolecules by a combination of the fundamental hydrodynamic approaches, i.e., analytical ultracentrifugation, intrinsic viscosity, translation diffusion, and size exclusion chromatography resolving the essential macromolecular characteristics—molar mass and hydrodynamic size as well as their distribution, shape, and conformation.

Series of copolymers of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride containing from 1.5 to 17% mol % of charged units were obtained by partial hydrolysis of poly(N-methyl-N-vinylacetamide). A complex of hydrodynamic investigations of their diluted solutions (viscous flow, velocity sedimentation, translational diffusion) was performed in 0.2 M NaCl in order to determine the molecular characteristics of copolymers. Viscosimetric investigations were performed in salt-free solution (ionic strength ~10–6 M) to study intrachain electrostatic interactions; the influence of charge linear density on the sizes of polyelectrolyte macromolecules was studied under these conditions. The examination of hydrodynamic volumes, equilibrium rigidity, and/or swelling coefficients of charged chains was performed.

Fractions of the copolymer of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride containing 15.7 ± 0.5% of charged units are obtained by radical polymerization, fractionation, and hydrolysis. Viscous flow, velocity sedimentation, and translational diffusion of their dilute solutions are studied in 0.2 M NaCl. Viscosimetric studies are also carried out in a wide range of ionic forces: from the minimum (~10–6 mol/L) to the maximum (6 mol/L). The hydrodynamic volumes and equilibrium rigidity of the copolymer under study are compared with the data obtained earlier for an uncharged homopolymer and a copolymer with a higher linear charge density (~44% of charged units) in solutions with different ionic strength. The correspondence of the values obtained to the theories of Odijk, Skolnik, and Fixman (OSF) as well as Dobrynin is discussed.

Poly( l -lactide) and poly( d , l -lactide) samples have been synthesized through ring-opening polymerization. The homological series of two poly(lactide)s have been studied in 1,4-dioxane solutions by a complex of methods: molecular hydrodynamics, molecular optics, NMR, and optical rotation. The 1 H and 13 C NMR spectroscopy and optical rotation proved the different stereo isomeric composition of poly( l -lactide) and poly( d , l -lactide) polymer series. The P- l -LA series are isotactic polymers, whereas the P- d , l -LA polymer series are atactic or syndiotactic ones. The hydrodynamic volume of poly( l -lactide) macromolecules was found to be larger than that for poly( d , l -lactide) macromolecules. Hydrodynamic studies were performed for P- l -LA series in the range of molar masses: 3.5 M × 10 −3 , g/mol d , l -LA series in the range: 1.6 M × 10 −3 , g/mol l -lactide chains in solution exhibit higher equilibrium rigidity than poly- d , l -lactide chains, which is explained by different chain tacticity. For the first time the birefringence of solution of two investigated types of poly(lactide) macromolecules in mechanical and electrical fields was studied. Both birefringence methods demonstrate the net differences between optical properties of P- l -LA and P- d , l -LA chains and confirm the conclusion made from the hydrodynamic study. Comparisons with the literature data concerning intrinsic viscosity values and chain rigidity parameters have been made.

Birefringence in solutions and films of poly[4,4'-bis(4''-N-phenoxy)diphenylsulfon]imide of 1,3-bis(3',4-dicarboxyphenoxy)benzene macromolecules is studied. The method of birefringence in the flow of polymer solutions in DMF allows one to determine the proper specific optical anisotropy of the repeating unit of chain βM = +15 × 10–27 cm3 mol/g. Spontaneous birefringence in polymer films of different thickness is studied under various incidence angles of a polarized beam. The total data analysis allows one to estimate the orientation order parameter of polymer chain fragments in the vicinity of surface S0 =–0.01, which is typical of flexible-chain polymers.

In-depth characterization of pharmaceutically relevant polymers plays a pivotal role in many areas, including nanoscience, gene therapy, analytical and polymer chemistry etc. Notwithstanding substantial efforts spent in this area, there are still unresolved challenges and one of the most demanding problems is the determination of absolute molar masses of a broad range of biocompatible cationic polymers. Hereby, we present a combined analytical approach for a distinct and self-consistent characterization of a series of linear poly(ethylene imine)s (PEIs) consisting of six in-house prepared PEIs (0.9 kDa < Mtheor < 250 kDa) and three commercially available linear PEIs (Polyscience labeled as 2.5 kDa, 25 kDa, and 250 kDa). The polymers were studied, in 0.2 M NaBr methanol, by the methods of molecular hydrodynamics: analytical ultracentrifugation, intrinsic viscosity and translational diffusion measurements. Absolute values of the molar masses were evaluated by the classical sedimentation-diffusion analysis resulting in the following range: 1.1 kDa < M < 13.9 kDa. It was demonstrated that the molar masses reported by the manufacturer, as well as theoretical and/or molar masses evaluated by common SEC analysis, are significantly overestimated. The complete set of Kuhn–Mark–Houwink–Sakurada scaling relations shows linear trends over the whole range of the molar masses, whilst the determined scaling indices virtually correspond to the homologous series characterized by a coil conformation ([η] = 0.255 × M0.56; s0 = 0.015 × M0.48; D0 = 994 × M−0.52). The conformational characteristics of LPEI, i.e. equilibrium rigidity (the Kuhn segment length) and the diameter of the PEI chains, were evaluated for the first time and constitute A = 1.9 ± 0.6 nm and d = 0.4 ± 0.2 nm, respectively. The presented self-sufficient analytical approach covers an important area of thorough polymer characterization by nowadays alternative but fundamental hydrodynamic methods allowing for complete structural and molecular analysis of almost any macromolecules in solution.

A study was made of spontaneous surface birefringence observed in pullulan films when a tilted polarized beam is passed through a plain polymer film. Birefringence was explored as a function of the angle of beam incidence and the film thickness. The orientational order parameter was estimated for pullulan chains located in the near-surface layers of films. The results were compared with data from earlier studies of other polysaccharides.

Properties of soluble polyetherimide samples are studied via molecular-hydrodynamics methods. According to the sedimentation–diffusion analysis, the molecular masses of the samples are in the range (5–65) × 103 g mol–1. Scaling ratios relating hydrodynamic characteristics to molecular mass are ascertained, and the conformational characteristics of polyetherimide molecular chains are determined. The statistical segment calculated from the translational- and rotational-friction data is 2.7 ± 0.7 nm. A comparison of this value with the statistical segment calculated for freely jointed chains yields a rotation-hindrance parameter of 1.16.

Poly(L-lactic acid) and poly(D,L-lactic acid) samples have been synthesized through ring-opening polymerization. Studying homological series of two poly(lactic acids) by molecular hydrodynamics and optical methods has shown that poly-L-lactide chains in solution exhibit higher equilibrium rigidity than poly-D,L-lactide chains, which is explained by different chain tacticity.

Hyperbranched poly(ethylene glycol) copolymers were synthesized by random anionic ring-opening multibranching copolymerization of ethylene oxide with glycidol as a branching agent, leading to poly(ethylene glycol) structure with glycerol branching points. Extending the available range of molar masses by novel synthesis strategies, a limited extent of control over the degree of polymerization was achieved by variation of the solvent in this copolymerization. Generally, absolute molar mass characterization of hyperbranched polymers still represents an unresolved challenge. A series of the hyperbranched poly(ethylene glycol)-co-(glycerol) copolymers (hbPEGs) of a wide range of molar masses (1400 < M < 1 700 000 g mol–1), degree of branching (DB) = 0.04–0.54, and moderate polydispersity (Mw/Mn) ≈ 2.1 ± 0.2 were studied, in both water and dimethylformamide by the methods of molecular hydrodynamics. Analytical ultracentrifugation, intrinsic viscosity, translational diffusion measurements, and SEC were combined....

The flow birefringence of aqueous solutions of poly(N-methyl-N-vinylacetamide) macromolecules for samples of various molecular masses is studied. It is found that the sign of birefringence changes from positive to negative with a decrease in molecular mass in accordance with the manifestation of the macroform effect on condition that the value of the inherent optical anisotropy of macromolecules is negative. With the use of the macroform-effect theory in the Maxwell phenomenon of polymer solutions, the inherent optical anisotropy of the repeating polymer unit is estimated as (a ‖−a ⊥) = −(5 ± 1) × 10−25 cm3. In turn, the value of (a ‖−a ⊥) makes it possible to separate structural and orientational contributions to the effect of spontaneous birefringence for films of various thicknesses that are cast from aqueous solutions of poly(N-methyl-N-vinylacetamide). The parameter of orientational order of chain fragments for this polymer in the near-surface layers of the films is −(0.05 ± 0.01).

Brush-shaped molecular stars of poly(ɛ-caprolactone)-block-poly(oligo(ethylene glycol) methacrylate) are synthesized, their hydrodynamic properties are studied, and their molecular characteristics are measured. For dilute solutions of the copolymers in acetone, viscous flow, velocity sedimentation, and translational diffusion of the macromolecules are investigated. The molecular masses of the copolymers are determined via the Svedberg relation. Correlations between hydrodynamic characteristics and molecular masses in the range 46 < M × 10−3 g mol−1 < 266 are obtained. The existence of scaling relationships makes it possible to infer that the resulting copolymers belong to a hydro-dynamically similar series of macromolecules: hydrodynamic homologs. It is shown that copolymer macromolecules have a denser organization in space than that of both linear macromolecules and conventional molecular stars. A model of macromolecules of poly(ɛ-caprolactone)-block-poly(oligo(ethylene glycol) methacrylate) copolymers that is based on their hydrodynamic characteristics is discussed.

Two series of highly charged linear aliphatic polymers—sodium polystyrene-4-sulfonate and random copolymer of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride—were studied in water solution without added salts and in solutions containing up to 5 M NaCl. Intrinsic viscosity in salt-free solutions was estimated by a method proposed earlier [Pavlov et al. Russ. J. Appl. Chem. 2006, 79, 1407–1412]. Molecular characteristics were obtained in 0.2 M NaCl. The polyelectrolytes were studied in more than 10-fold range of molar mass. Qualitatively, the conformational status of the polyelectrolyte chains in different ionic strength was defined with the Kuhn–Mark–Houwink–Sakurada plots normalized by the value of linear chain density. In salt-free solution both polyelectrolytes could be attributed to extra rigid chains with the statistical segment length of 650 nm for sodium polystyrene-4-sulfonate and 100 nm for copolymer chains. Such statistical segment lengths are provided by short-range electrostat...

The hydrodynamic characteristics of macromolecules of a random copolymer of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride containing 43.6% charged units in the molecular-mass range of 27 × 103 to 355 × 103 are studied. For solutions in 0.2 M NaCl, sedimentation and translational-diffusion coefficients are determined. For salt-free solutions and for solutions in 0.2 and 5.0 M NaCl, the intrinsic viscosities of the fractions are found. The lengths of the statistical segments of the chains are estimated in terms of the Gray-Bloomfield-Hearst theory. The behavior of the polycation, whose uncharged counterpart is a hydrophilic polymer, is compared to the behavior of poly(sodium 4-styrenesulfonate), whose uncharged counterpart is a hydrophobic polymer. The comparison is based on normalized scaling relations. It is shown that the level of compaction of macromolecules of strong polyelectrolytes at a high ionic strength is determined by the degree of hydrophobicity of their polymer chains. Polyelectrolytes based on hydrophilic polymers cannot be compacted into a preglobular state; their chains preserve a swollen coil conformation up to maximally high values of ionic strength.

Star-brush-shaped poly(e-caprolactone)-block-poly(oligo(ethylene glycol) methacrylate (PCL-b-POEGMA) macromolecules were synthesized and studied by molecular hydrodynamic methods. The values of the intrinsic viscosity, the velocity sedimentation coefficient, the translational diffusion coefficient, and the frictional ratio were obtained in acetone. Molar masses (M) were determined by the Svedberg relation, and the correlations between the hydrodynamic values and the molar mass were obtained in the range of 19 < M × 10–3 g mol–1 < 124. Comparison of the scaling indexes of the intrinsic viscosity and sedimentation velocity coefficient versus molar mass corresponding to the conventional four-arm stars macromolecules with that of the star-brush-shaped copolymer macromolecules shows that the star-brush-shaped PCL-b-POEGMA macromolecules have the more dense organization in space which is connected with their different topology in contrast to the conventional stars macromolecules. The model of the PCL-b-POEGMA m...

Amphiphilic star-shaped poly(e-caprolactone)-block-poly(oligo(ethylene glycol)methacrylate) [PCLa-b-POEGMAb]4 block copolymers with four arms and varying degrees of polymerization for the core (PCL) and the shell (POEGMA) were used to investigate the solution behavior in dilute aqueous solution using a variety of techniques, including fluorescence and UV/Vis spectroscopy, dynamic light scattering, analytical ultracentrifugation, and isothermal titration calorimetry. Particular emphasis has been applied to prove that the systems form unimolecular micelles for different hydrophilic/lipophilic balances of the employed materials. In vitro cytotoxicity and hemocompatibility have further been investigated to probe the suitability of these structures for in vivo applications. A novel fungicide was included into the hydrophobic core in aqueous media to test their potential as drug delivery systems. After loading, the materials have been shown to release the drug and to provoke therewith an inhibition of the growth of different fungal strains.

In the present study, the complexation between linear 13.4 kDa poly(ethylene imine) (LPEI) and plasmid DNA was investigated. Analytical ultracentrifugation (AUC) was used for size and molar mass determination. Additionally, the morphology was studied by scanning force microscopy. The polyplex formation was investigated in a wide range of PEI nitrogen to DNA phosphate ratios (N/P). At N/P ratios below 1, the PEI/DNA complex formation is characterized by an incomplete DNA condensation and the formation of the primary DNA/PEI complexes. The merging of the initially formed polyplexes occurs at N/P ~2, resulting in the formation of polyplexes with much larger size and high aggregation rate. Stable and uniform polyplexes were formed at N/P10, with average sizes of the polyplexes of about 170 ± 65 nm. The content of uncomplexed PEI chains in the polyplex dispersion was estimated at four different N/P ratios, 6.2, 11.6, 28.6, and 57.8, by combining preparative centrifugation with a copper complex assay and by sedimentation velocity analysis as an alternative method. It is demonstrated that virtually all added PEI binds to the DNA at N/P2.5; further addition of PEI results in the appearance of a large amount of free PEI in solution. Nevertheless, PEI is able to bind in the whole range of N/P ratios tested. According to the data collected by sedimentation velocity analysis and scanning force microscopy, the single PEI/DNA complexes are composed on average of 8 to 32 single condensed DNA plasmids and 70 ± 25 PEI molecules.

The development and optimization of processes involving polymeric molecules require determination and monitoring of key molecular characteristics of the polymer. Samples of poly-N-methyl-N-vinylacetamide were synthesized and fractionated. Partial hydrolysis of the homopolymer fractions was performed, and fractions of a random copolymer of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride were obtained. The molecular weights and conformational parameters of the homo- and copolymers in 0.2 M aqueous NaCl were determined by methods of molecular hydrodynamics.

Poly(alkyl methacrylate) copolymers embedding bidentate trzpy chelating units as comonomer in the side chains are synthesized utilizing the controlled radical RAFT polymerization process. The free trzpy units are complexed by iron(II) and cobalt(II) ions, which results in characteristic UV-Vis absorption bands and an increase of solution viscosity. The intramolecular complexation with Co(II) ions is studied by different analytical ultracentrifugation experiments. Following the addition of a small amount of Co(II) ions, a significant decrease of the intrinsic sedimentation coefficient is observed that can be explained by the elongation of the individual polymer coils due to the electrostatic repulsion of the coordinated Co(II) ions.

Brush-like poly{4-[4-(hexyloxy)phenyl]ethynylphenyl methacrylate}s are synthesized using RAFT polymerization, fractionated and studied by molecular hydrodynamic methods. The values of the velocity sedimentation coefficient, the frictional ratio, and the intrinsic viscosity are obtained in toluene. The conformational and structural parameters of the studied polymer chains are estimated by the use of theories that describe the hydrodynamic behavior of the wormlike cylinders without intra-chain excluded volume effects and the hydrodynamic behavior of bending rods. The intrinsic viscosity data obtained for poly{4-[4-(hexyloxy)phenyl]ethynylphenyl methacrylate}s and for other brush-like macromolecules are discussed in terms of a doubly-normalized scaling plot.

New ditopic 2,6-bis(1,2,3-triazol-4-yl)pyridine ligands featuring a π-conjugated spacer and clicked-on solubilizing groups were employed in the synthesis of Ru(II) metallo-supramolecular polymers that exhibit an intense metal-to-ligand charge transfer absorption in the visible light region. The coordination polymers obtained were studied in solution by means of size exclusion chromatography and analytical ultracentrifugation, revealing a comparably high molar mass and moderate rigidity. Investigations in the solid state by atomic force and transmission electron microscopy confirmed the formation of rod-like polymers. Furthermore, film preparation by drop-casting showed good film-forming properties. Thus, the solution-processable, photoredoxactive polymers might be applicable in solar cells.

Translational friction and viscosity of dilute solutions of sodium poly(styrene-4-sulfonate) with molecular masses of M = (5 × 104)−(85 × 104) are studied at different concentrations of low-molecular-mass salts. Molecular masses of the polymer are determined from the sedimentation-diffusion data. The study of the correlation between molecular masses and hydrodynamic characteristics resulted in ascertainment of the Kuhn-Mark-Houwink-Sakurada relationships for salt-free aqueous solutions of the polymer and solutions of the polymer in 0.2 M NaCl, 4.17 M NaCl, and 1.0 M KCl. It is shown that, as the ionic strengths of solutions are varied from minimum (H2O) to maximum (4.17 M), macromolecules of the strong polyelectrolyte sodium poly(styrene-4-sulfonate) change their conformations from rigid rods to coils and, then, approach a globular conformation. In terms of the Gray-Bloomfield-Hearst and Yamakawa-Fujii theories and within the framework of the weakly bent cylinder model, the statistical Kuhn segment length and the hydrodynamic diameter of sodium poly(styrene sulfonate) chains are estimated in 0.2 and 4.17 M NaCl, 1.0 M KCl, and salt-free aqueous solutions. The electrostatic component of the equilibrium rigidity is taken into account within the framework of the Odijk-Fixman-Skolnick and Dobrynin theories.

Linear macromolecules constitute a broad class of synthetic and natural polymers which are highly useful in various technologies and represent the key molecular systems in living nature. The study of the molecular characteristics of these polymers represents an important problem in fundamental and applied science. The methods of molecular hydrodynamics have been and remain an important way of studying the molar mass, molar mass distribution, size and conformation of linear polymers. This paper discusses the approaches to the problems of hydrodynamic methods, in particular analytical velocity ultracentrifugation, in the study of various types of linear macromolecule. The velocity sedimentation data were processed with three different methods: Sedanal and Sedfit software, and the classical approach of evaluating the rate at which the sedimentation boundary moves. The Sedfit program also allows an evaluation of the frictional ratio values, i.e., the coefficient of translational diffusion. It will be discussed for which systems the estimation of the frictional ratio obtained by Sedfit is adequate and for which it is not. The applications of other hydrodynamic methods (intrinsic viscosity, translational diffusion) are also discussed with a view to obtaining the conformational characteristics of linear macromolecules.

A series of Ru(II) heterodinuclear complexes of ABA-type with electron-deficient bis-terpyridines as building blocks was synthesized by (R-tpy)Ru(III)CI(3) complexation. These compounds were characterized by NMR spectroscopy, MALDI-TOF, ESI-TOF mass spectrometry, and elemental analysis. The results were compared with a coil-rod-coil Ru(II) metallo-supra-molecular copolymer, which was synthesized by bis-complex formation between a hydrophilic omega-terpyridine poly(ethylene glycol) Ru(II) mono-complex and a hydrophobic bis-terpyridine-functionalized rigid core. This amphiphilic Ru(II) triblock copolymer showed self-assembly to clusters and micelles in aqueous solution, which was studied by transmission electron microscopy and dynamic light scattering. Applying velocity sedimentation experiments the number of amphiphilic Ru(II) ABA triblock copolymer molecules within the micelles could be estimated. Finally, the photophysical properties of the Ru(II) supramolecular assemblies were investigated by UV-vis spectroscopy. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 1396-1408, 2011

High-velocity sedimentation, translational isothermal diffusion, and viscometry in H2O and DMF are used to investigate the samples and fractions of poly(N-methyl-N-vinylacetamide) synthesized by free-radical polymerization and fractionated in a chloroform-diethyl ether system. Molecular masses M and the Mark-Kuhn-Houwink-Sakurada relations are obtained for the fractions in the molecular mass range M × 10−3 = 3.5−540.0. The negative temperature coefficient of intrinsic viscosity is revealed for both solvents. The length of the Kuhn statistical segment and the hydrodynamic diameter of poly(N-methyl-N-vinylacetamide) macromolecules are estimated; the hydrodynamic volumes occupied by water-soluble poly(N-methyl-N-vinylacetamide), poly(1-vinyl-2-pyrrolidone), poly(vinylformamide), and pullulan molecules are compared.

Nanoprecipitation represents an effective method for the production of polymeric nanoparticles. This technique was used to prepare nanoparticles from solutions of poly-(methyl methacrylate) and its copolymers. Since the regulation of main parameters like particle size, particle size distribution, and molar particle mass is very important for future applications, the stable nanoparticle dispersions were examined by scanning electron microscopy, velocity sedimentation, and dynamic light scattering, whereby advantages and disadvantages of each characterization techniques are discussed. Polydispersities of particle size distributions are determined by the ratio of d w /d n , where d w and d n are weight- and number-average diameters, respectively. The particle characteristics strongly depend on the chemical structure of the polymers and the way of preparation and, therefore, vary in the studied cases in the range of 6 < d w < 680 nm, whereas the polydispersity index d w/ d n changes in the range of 1.02 to 1.40. It is shown that nanoparticles in a desirable size range can be prepared by solvent-nonsolvent methods (dialysis technique or dropping technique).

Two zinc(II)- and two ruthenium(II) containing π-conjugated metallo-polymers were synthesized and characterized in detail. We could prove by SEC, analytical ultracentrifugation (AUC) and viscosimetry the ruthenium(II) metallo-polymers to be high molar mass materials (M(fs) = 20 000 g · mol(-1) Ru1-2; M(fs) = 34 000 g · mol(-1) Ru1) exhibiting intrinsic viscosities of up to [η] = 192 · cm(3) · g(-1) . Applying spin-coating we produced homogeneous films of the polymers and could, subsequently, investigate the photophysical properties in the solid state. Introducing the Ru(II) metallo-polymers mixed with PCBM[60] as photoactive layer in bulk-heterojunction solar cells resulted in very low efficiencies due to morphology problems.

Analytical ultracentrifugation is one of the key methods among the molecular hydrodynamic methods of polymer science, biophysics, and colloid science. The aim of this work is to demonstrate the possibilities of a modern instrument, the Beckman XLI Analytical Ultracentrifuge, coupled with the now available software for the molecular characterization of synthetic polymers. For this purpose the classical system polystyrene in methyl ethylketone was investigated. The samples of low polydispersity index were studied in a 1000-fold interval of molar mass values. The exhaustive analysis of such hydrodynamic values as velocity sedimentation coefficient, frictional ratio, concentration Gralen coefficient, and intrinsic viscosity, was done. The values of partial specific volume, refractive index increment, and hydrodynamic invariants were also determined and discussed. The estimation of the statistical segment length (or persistent length) of polystyrene chains was made taking into account the intrachain excluded volume and draining effects (Gray-Bloomfield-Hearst theory). The obtained experimental data and results of its analysis allow the conclusion that the method of velocity sedimentation, coupled with the numerical solution of the Lamm equation, represents a powerful absolute characterization method for molar mass determination of flexible polymers of low polydispersity in relatively poor solvent.

For samples of various molecular masses, the flow birefringence of poly(styrene-4-sulfonate sodium) macromolecules in aqueous solutions at various ionic strengths is studied in relation to the concentration of NaCl. It is shown that the sign of birefringence changes from negative to positive with an increase in the ionic strength of a solution. Application of the macroform theory to the Maxwell effect makes it possible to estimate the intrinsic optical anisotropy of the repeating unit of poly(styrene-4-sulfonate sodium) (a||- a⊥) = −17 × 10-25 cm3), which nearly coincides with similar values known for atactic polystyrene and poly(κ-methylstyrene).

Samples of poly(styrene−diphenylethylene) copolymers of narrow molar mass distribution were studied by molecular hydrodynamic methods. The values of velocity sedimentation coefficient, frictional ratio, translational diffusion coefficient, and intrinsic viscosity were measured in toluene. It is shown that the method of velocity sedimentation, coupled with the numerical solution of the Lamm equation (Sedfit program), can be considered as an absolute method of molar mass determination. The correlations between the hydrodynamic values and the molar mass were obtained. A new Multi-HYDFIT program was applied to obtain the conformational parameters of poly(styrene−diphenylethylene) copolymer chains unaffected by intrachain excluded volume effects.

Molecules of three cyclodextrins have been studied by molecular hydrodynamics in water, dimethylformamide, and dimethylsulfoxide. The estimated molecular masses correlate well with the calculated values. The hydrodynamic radii of cyclodextrin molecules have also been determined. The experimental data have been compared with theoretical calculations for toroidal molecules. These data can be reconciled on the assumption that solvent molecules are adsorbed on the external surface of cyclodextrin molecules.

Three well-known representatives of the cyclodextrin family were completely characterized by molecular hydrodynamics methods in three different solvents. For the first time the possibility of an estimation of velocity sedimentation coefficients s between 0.15 and 0.5 S by the numerical solution of the Lamm equation is shown. Comparison of the experimental hydrodynamic characteristics of the cyclodextrins with theoretical calculations for toroidal molecules allows an estimation of the thickness of the solvent layers on the surface of cyclodextrin molecules.

The structure of the surface layers of thin films cast from water-soluble derivatives of cellulose—methyl cellulose and hydroxypropyl methylcellulose—has been studied by the methods of an oblique polarized beam and molecular hydrodynamics. It has been demonstrated that the molecular chains of the polymers under study are characterized by a high degree of order in surface film layers. The orientational order of molecular chains demonstrates a strong molecular mass dependence. This effect is associated with the concentration of terminal segments whose orientational order parameter relative to the film surface differs from the corresponding value of internal segments composing the molecular chain. The quantitative estimates of the orientational order parameter of terminal and internal segments have been performed.

The general principles for the interpretation of the sedimentation velocity for linear macromolecules are discussed in combination with the characteristics obtained by other hydrodynamic methods. The several levels of self-sufficiency of the sedimentation velocity method are demonstrated. They include scaling correlation between velocity sedimentation coefficient s0 and concentration coefficient \( {k}_s={K}_{sks}{s_0}^{bks} \), application of the sedimentation parameter β s for molar mass estimation, and qualitative conformation zoning of linear macromolecules using the normalized double logarithmic plots (k s M L vs [s]/M L ). The last example of self-sufficiency of the method is the study of the concentration dependence of the sedimentation velocity in combination with continuous c(s) distribution using general scaling law model of Sedfit software. This model allows to establish the relationship \( {s}_0={K}_s{M}^{bs} \) for flexible polymers and perform further gross conformational analysis and analysis of the molar mass distribution. It is shown that the K s coefficient is strongly dependent on the polymer concentration.

The conformational properties of macromolecules of chitosan and its copolymers with acrylamide in a mixed solvent 0.33 M CH3COOH + 0.3 M NaCl have been investigated by means of translation diffusion and viscometry. The copolymer macromolecules in a solvent suppressing polyelectrolyte effects possess a higher intracoil density (ρav = 0.010 g/cm3) than the chitosan macromolecules (ρav = 0.006 g/cm3), even though the hydrodynamic radius Rh of chitosan is smaller by a factor of ∼1.5.

Spontaneous birefringence in films prepared by free evaporation of a solvent from solutions of sulfated phenyl-containing polymers has been investigated in relation to the thickness of films and the incidence angle of a polarized light beam. It has been demonstrated that not only the value but also the sign of the coefficient of surface birefringence depends on the mode of incorporation of benzene rings into a polymer chain. The structural and orientation factors determining the spontaneous birefringence in the films have been distinguished. The results are compared with the data available for the films of water-soluble polysaccharides. The degree of order in the near-surface layers of polymer films cast from solutions is determined by the statistical segment length of macromolecules and is independent of the chemical nature of chains in the number of water-soluble polymers under consideration.

The spontaneous ordering of fragments of chain molecules near the surface in polymer films is described in terms of the multichain model that allows for local intra-and interchain orientational interactions of chain segments and for transverse fluctuation of their orientation in the approximation of strong planar-orientation order in the layers. Chain packing in the plane-ordered state is impossible unless the interchain interaction parameter has a value of b = 2K 2/k B T > b c. The value of b c decreases with a growth in chain rigidity (parameter a = 2K 1/k B T). The calculated dependence of the limiting values of the quadrupole orientation order parameter S 0 on the length of the Kuhn statistical segment A = 2a reasonably well describes the experimental data obtained in a study of polymer-homolog (polysaccharide) films by means of the tilted polarized-beam technique at an interchain interaction parameter of b = 1.75. The monolayer thickness (d ≅ 10 mn) is films of some polysaccharides was calculated from the fit of the theoretical to the experimental dependences of the orientational order parameter and the birefringence on the number of layers.

The parameter of the orientational order of polymer chain fragments near the substrate (film) surface in relation to the degree of asymmetry of the statistical segment of the macromolecule was discussed in terms of the model of adsorption of rigid cylinders on the substrate surface. The theoretical parameters of the orientational order were analyzed and compared with the experimental data for films of polysaccharides, sulfated phenyl-containing polymers, and polytrimethylsilylpropynes.