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Recent results on synthesis, structural, and physicochemical studies of complexes based on detonation nanodiamonds modified with metal-organic molecules with functional magnetic and fluorescent pro...

A liquid biopsy based on circulating small extracellular vesicles (SEVs) has not yet been used in routine clinical practice due to the lack of reliable analytic technologies. Recent studies have demonstrated the great diagnostic potential of nanozyme-based systems for the detection of SEV markers. Here, we hypothesize that CD30-positive Hodgkin and Reed–Sternberg (HRS) cells secrete CD30 + SEVs; therefore, the relative amount of circulating CD30 + SEVs might reflect classical forms of Hodgkin lymphoma (cHL) activity and can be measured by using a nanozyme-based technique. A AuNP aptasensor analytics system was created using aurum nanoparticles (AuNPs) with peroxidase activity. Sensing was mediated by competing properties of DNA aptamers to attach onto surface of AuNPs inhibiting their enzymatic activity and to bind specific markers on SEVs surface. An enzymatic activity of AuNPs was evaluated through the color reaction. The study included characterization of the components of the analytic system and its functionality using transmission and scanning electron microscopy, nanoparticle tracking analysis (NTA), dynamic light scattering (DLS), and spectrophotometry. AuNP aptasensor analytics were optimized to quantify plasma CD30 + SEVs. The developed method allowed us to differentiate healthy donors and cHL patients. The results of the CD30 + SEV quantification in the plasma of cHL patients were compared with the results of disease activity assessment by positron emission tomography/computed tomography (PET-CT) scanning, revealing a strong positive correlation. Moreover, two cycles of chemotherapy resulted in a statistically significant decrease in CD30 + SEVs in the plasma of cHL patients. The proposed AuNP aptasensor system presents a promising new approach for monitoring cHL patients and can be modified for the diagnostic testing of other diseases.

Catalytic complexes of photosensitizer Radachlorin® (sodium salts of chlorin e6, chlorin p6, purpurin 5) with polyvinylpyrrolidone (PVP) and detonation nanodiamonds (DND) have been synthesized and studied by optical absorption spectroscopy, luminescence excitation, dynamic light scattering and viscometry methods. Binary complexes PVP-Radachlorin® demonstrated electrostatic and donor–acceptor binding of Radachlorin® with PVP detected by spectrophotometric titration when Q-band (~650 nm) displayed bathochromic shift and enhancement with isosbestic point indicating a single type of binding sites. Similar changes in luminescence emission spectra in binary complexes were observed earlier at higher polymer contents. The yield of singlet oxygen under UV-irradiation (405 nm) of Radachlorin® increased in PVP-Radachlorin® complex. Dynamic light scattering and viscometry confirmed the stability of complexes and no agglomeration. Ternary complexes DND-PVP-Radachlorin® provided a generation of singlet oxygen by UV-irradiation exciting diamonds which do not emit but transfer the energy to surrounding molecules. The results allow develop effective catalysts for chemical and medical applications as well as for disinfection, active filtration and cleaning air, water, surfaces. Novel catalytic complexes based on chemically inert diamonds are resistant to the singlet oxygen and profitable for long-term usage.

Using the commercial derivative of norbornene—5-ethylidene-2-norbornene—a series of three isomeric homopolymers with different structure of the backbone is synthesized, and the effect of the chain structure on the gas-transport behavior of polynorbornenes is studied. The gas-transport characteristics of the polymers are presented together with data on the conformation properties of molecules of addition and metathesis polynorbornenes. The effect of the structure of side substituents on the equilibrium rigidity of addition polynorbornenes is confirmed by the example of poly(5-ethylidene-2-norbornene) and poly(5-vinyl-2-norbornene).

Film-forming polymers with side substituents involving carbon–carbon double bonds are of great interest as compounds of promise for further modification. In this work, the possibility of synthesizing one of the polymers of this type—additive poly(5-ethylidene-2-norbornene) from a commercially available monomer—has been shown and the molecular properties of a series of the polymer samples in the range of molecular masses of (1–16) × 105 have been studied by methods of hydrodynamics and light scattering in chloroform. The molecular mass dependences of the hydrodynamic characteristics of the polymer have been determined. It has been established that the presence of ethylidene side substituents is responsible for an increase in the equilibrium rigidity of this carbon-chain polymer to 6.2 nm, which is much higher as compared with the typical flexible-chain vinyl polymers and is higher than the value for the known poly(5-trimethylsilylnorbornene-2), the significant value of the Kuhn segment of which approximating 5 nm is due to the presence of bulk silicon-containing side groups.

The aim of the study was to explore the polyethylene glycol–dextran two-phase polymer system formed in human plasma to isolate the exosome-enriched fraction of plasma extracellular nanovesicles (ENVs). Systematic analysis was performed to determine the optimal combination of the polymer mixture parameters (molecular mass and concentration) that resulted in phase separation. The separated phases were analyzed by nanoparticle tracking analysis and Raman spectroscopy. The isolated vesicles were characterized by atomic force microscopy and dot blotting. In conclusion, the protein and microRNA contents of the isolated ENVs were assayed by flow cytometry and by reverse transcription followed by quantitative polymerase chain reaction (RT-qPCR), respectively. The presented results revealed the applicability of a new method for plasma ENV isolation and further analysis with a diagnostic purpose.

Polytricyclononenes are new polymers having high permeability values not only for atmospheric gases, but also gaseous hydrocarbons. Thin films (≤100 μm) used in gas-separation membrane technologies are necessary to be studied to improve the gas transport properties of these polymers. The structure of polytricyclononene films with two vicinal side substituents Si(CH3)3 in a monomer unit synthesized via additive polymerization scheme is studied in this work by a small-angle neutron scattering method. As a whole, the amorphous film has a local orientation order due to chain fragments with spiral conformation. The size of the ordered regions is comparable to the length of units correlations in the polymer chain (Kuhn segment) and is 8–9 nm. Free volume and type of voids (pores) formed in the polymer film due to inhomogeneous packing are also found.

The synthesis and gas-transport properties of new metathesis-type polynorbornenes bearing fluoroorganic side groups are reported. The necessary monomers, fluorosubstituted exo-norbornene derivatives (exo-tricyclononenes), were obtained using one-step method based on stereo- and regioselective [2 + 2+2]-cycloaddition of quadricyclane and fluoroalkenes. A set of high molecular weight polymers with different side groups were prepared from the synthesized F-substituted exo-tricyclononenes over the 1-st generation Grubbs catalyst. Permeability and diffusion coefficients of various gases (He, H2, O2, N2, CO2, CH4) in these poly-exo-tricyclononenes were determined for the first time and new relationships between polymer structure and gas permeability were established. Metathesis poly-exo-tricyclononene bearing four CF3-groups in each monomer unit displayed the highest gas permeability for the tested gases among metathesis polynorbornenes with F-organic substituents reported so far.

Secondary polyamine in protonated salt form – poly(diallylammonium trifluoro-acetate) is characterized as representative of polymer series based on N,N-diallyl-ammonium. Its hydrodynamic behavior in 1 M NaCl has been compared with the other series members – quaternary poly(diallyldimethylammonium chloride) and tertiary poly(diallylmethylammonium trifluoroacetate). It was shown that these polymers belong to semirigid class whose Kuhn segment length ∼4 nm just slightly depends on chemical structure at high ionic strength. As specific for secondary polyamine, the sensitivity to proton equilibrium in solution and counter ion type was detected resulting in great difference of its Mark–Kuhn–Houwink equations from the quaternary analogue at the same conditions.

The molecular properties of the additive poly(bis(trimethylsilyl)tricyclononene) with the vicinal position of two side groups Si(CH3)3 in the monomer unit are studied for the first time, and its conformational and kinetic properties are compared with those of the isomer with the geminal position of the same groups. Using the methods of static/dynamic light scattering and viscometry for the samples of the vicinal isomer, the hydrodynamic parameters of molecules are determined and their molecular mass dependences in toluene are ascertained. In addition, the Kuhn segment length of this isomer is estimated. The kinetic rigidity of vicinal and geminal isomers is evaluated by 1H NMR relaxation from the mobility of protons in Si(CH3)3 groups. The reasons behind different gas permeabilities of the films based on the polymers with the vicinal and geminal positions of Si(CH3)3 side groups in the monomer unit are discussed.

The homologous series of additive poly[3-(trimethylsilyl)tricyclononene-7] with two heminal substituents Si(CH3)3 in the side cycle of the monomer unit is studied for the first time via the methods of viscometry and static and dynamic light scattering in the range of molecular masses of (29–770) × 103. The scaling ratios for the intrinsic viscosity and the coefficient of translational diffusion of macromolecules in toluene at 298 K are obtained, and the equilibrium rigidity of the polymer chain is determined. The hydrodynamic and conformation properties of the polymer are compared to an analog with only one Si(CH3)3 substituent in the monomer unit. It is found that the introduction of the second side substituent in the heminal position increases the equilibrium rigidity of the additive poly[3-(trimethylsilyl)tricyclononene-7] by 1.4 times and has a far stronger effect on the kinetic rigidity of the polymer. With the use of the 1Н NMR relaxation method, it is shown that the mobility of side groups of the polymer with two substituents decreases significantly and the correlation times of hydrogen atoms of Si(CH3)3 groups exceed some 20 times the corresponding values for the analog with one Si(CH3)3 group in the monomer unit cycle.

With the use of the methods of hydrodynamics, the Kerr electrooptical effect, and dielectric polarization in solution, the molecular properties of a homologous series of poly[3-(trimethylsilyl)tricyclononene-7] samples synthesized via additive polymerization have been studied. Scaling relationships that describe how the intrinsic viscosities, diffusion coefficients, and sedimentation coefficients of macromolecules depend on their molecular masses in toluene at 298 K have been obtained. It has been shown that the additive poly[3-(trimethylsilyl)tricyclononene-7] has enhanced kinetic chain rigidity. According to hydrodynamic data, the length of the Kuhn segment for this polymer does not exceed 6.0 ± 0.6 nm, while the kinetic fragment estimated from electrooptical data is 4.3 nm. In terms of kinetic properties, the studied polymer is similar to wellknown poly[1-(trimethylsilyl)-1-propyne], with the specific morphology of its highly permeable films being determined by the large-scale mechanism of chain orientation.

A set of poly[bis(trimethylsilyl)tricyclononenes] bearing two trimethylsilyl side groups at geminal position in monomer unit has been synthesized by ring-opening metathesis polymerization technique and investigated via static and dynamic light scattering, viscometry and 1Н NMR relaxation in diluted solutions. Molecular properties of this type polymer have been under study for the first time. Its scaling relations and chain rigidity are obtained and compared to polymer synthesized by means of addition polymerization of the same monomer. There is shown that additive and metathesis polymers considerably differ by their chain rigidity, both equilibrium and kinetic. Metathesis analogue is typical flexible chain polymer characterizing by Kuhn segment length 1.6 nm, while the additive one, whose Kuhn segment is 5.6 nm, belongs to semirigid range. The influence of chain rigidity on thin film properties of substituted polytricyclononenes is also discussed because the synthesized by addition or metathesis routes polymers display very different gas permeability in films.

Spectral, luminescent and electro-optical properties of poly(9,9-dioctylfluorene), containing small quantity (1–2 mol%) of 2,1,3-benzothiadiazole comonomer units, obtained by means of either Suzuki or Yamamoto polycondensation reactions were studied and compared. The difference of luminescent properties of the two copolymers with nearly identical chemical compositions was explained by different molecular structure of their macromolecules. The films of Yamamoto type copolymer, containing, obviously, microblock sequences of 2,1,3-benzothiadiazole units, exhibit a nearly white electroluminescence (CIE x = 0.276, y = 0.274) with a high brightness (3747 cd/m 2 at 10 V), while the films of Suzuki type copolymer with randomly distributed isolated 2,1,3-benzothiadiazole fragments – green electroluminescence.

Molecular properties of N -[(2-hydroxy-3-trimethylammonium)propyl]chitosan (modified chitosan) series with the averaged quaternization degree 90% have been studied in comparison with the unmodified chitosan series by the method of translation isothermal diffusion, viscometry and static light scattering in dilute solutions in 0.33Ðœ ÐiН 3 ÐiООН+0.2Ðœ CH 3 ÐiООNa at pH 3.54. Molecular mass, translation diffusion coefficient, and hydrodynamic size of the homologues samples in the modified/unnmodified series have been determined as well as their chain rigidity and Mark-Kuhn-Houwink equations at acidic pH. It was established that the size of modified chitosan molecules might be smaller than the initial polysaccharide of an equal polymerization degree in the same solvent, which was explained by the change of thermodynamic conditions and the change of the ratio of thermodynamic/electrostatic contributions to the total chain rigidity. Quaternized chitosan molecules displayed the different hydrodynamic behavior in 0.33Ðœ ÐiН 3 ÐiООН+0.2Ðœ CH 3 ÐiООNa and in 0.2M NaCl (neutral pH). Solution properties of quaternized chitosan at neutral pH had been identified as the concentration dependent. The threshold influence of the secondary amino group protonation on the hydrodynamic properties of modified chitosan molecules was detected in 0.2M NaCl at the solute concentration range 0.001-0.004 g/cm 3 .

Some correlations between phase behavior parameters and molecular solution properties of disubstituted aliphatic/partially fluorinated aliphatic polyphosphazenes have been found to be due to their dependence on the side substituent length. Experimental study of the electro-optical Kerr effect and the dynamo-optical Maxwell effect in dilute solutions have showed that both types of polyphosphazenes exhibit an alteration of the effects’ sign when their aliphatic side chains reach a certain “critical” length (~5–6 carbon atoms). This phenomenon is explained by a change of the direction of primary axis of optical (deformational) polarizability in the monomer unit of polyphosphazenes with the “critical” length of side substituents. One of the consequences of the change of primary polarizability axis is an increasing of the angles between the dipoles induced by electric field and the permanent dipoles of the main chain. Additionally it was experimentally established that optical anisotropy of polarizability of monomer unit for the polymers under consideration is close to zero when their side substituents are consist of 5–6 carbon atoms. An absence or extremely small anisotropy of polarizability for macromolecules with the diverging directions of the permanent and induced dipoles has been considered as a general stimulus for additional ordering of disubstituted polyphosphazenes in the melt and for mesophase formation.

[60]Fulleropyrrolidine-containing poly(benzyl ether) dendrimers 1−4 were synthesized via 1,3-dipolar cycloaddition of amino acid and aldehyde derivatives and [60]fullerene. Their dielectric and electrooptical (Kerr effect) solution properties were studied and compared with poly(propyleneimine) dendrimers, namely DAB-dendr-(alkyl chain)n and DAB-dendr-(CN)n, and with known symmetrical and non-symmetrical poly(benzyl ether) dendrimers carrying benzyl groups ([Gx]-[C]-[Gx]) or benzyl and cyanobenzyl groups (CNn-[Gx]-[C]-[Gx+1]), respectively. It was shown that 1−4 display similar polar and electrooptical characteristics independent of their dendrimer generation. This is in contrast to the reference dendrimers for which a strong dependence of total dipole moment on dendrimer generation was observed.

We have studied applicability of reversible addition-fragmentation chain transfer/macromolecular design via the interchange of xanthate (RAFT/MADIX) method to radical cyclopolymerization of protonated diallylammonium monomer, namely diallylammonium trifluoroacetate (DAATFA), occurring with efficient chain transfer to monomer reaction. The latter drives to a significant extent polymerization, noticeably setting molecular weight, MW, of polymers and their polydispersity (polydispersity index (PDI) = 2.8–3.0). For the first time, upon DAATFA polymerization in presence of RAFT ethylxanthogenacetic acid (xanthate) in aqueous solutions at 70 °C, the side chain transfer reaction was inhibited and control of the polydispersity was achieved, the PDI = 1.2–1.3. The structural characteristic of poly(diallylammonium trifluoroacetate) (PDAATFA) polymers was analyzed via 1H and 13C NMR and IFS FTIR (ATR) spectroscopy. It was proved that the structure of polymers obtained by RAFT polymerization fully corresponds to the polymers PDAATFA containing cationic pyrrolidinium links and trifluoroacetate-counterions. At the optimal xanthate concentrations, the main products are polymers with the end dithiocarbonate group, i.e. macro-RAFT PDAATFA. Static/dynamic light scattering, viscometry and ultracentrifugation were used for polymers characterization. Molecular weight was determined by two independent methods: static light scattering (Mw) and hydrodynamic parameters analysis (MDη). The PDI Mw/Mn was calculated on the basis of Fujita approach, using the determined distributions of sedimentation coefficients. The experimental number average molecular weights, Mn, grow with polymerization time, 6700 g mol−1

Hydrodynamic properties of the homologous series of the homopolymer 2-deoxy-2-methacryla-mido-D-glucose and the copolymers of 2-deoxy-2-methacrylamido-D-glucose with unsaturated acids in 0.2 M NaCl are studied via static and dynamic light scattering, viscometry, refractometry, and translational diffusion. The copolymers synthesized via the free-radical copolymerization of 2-deoxy-2-methacrylamido-D-glucose with acrylic acid or methacrylic acid contain ∼20 mol % acid units. At this amount of acid units, the equilibrium rigidity of copolymer chains corresponds to that of homopolymer chains. The copolymers are distinguished by the hydrodynamic characteristics of molecules. The copolymer with methacrylic acid is similar to the homopolymer, whereas the copolymer with acrylic acid features substantially different parameters of relationships relating the hydrodynamic characteristics of homologs to their molecular masses.

Polyamides containing fragments of two cyanine chromophores in the main chain are synthesized, and their viscometric and electro-optical properties in solutions, as well as their stress-strain properties in films, are investigated. It is shown that the molecular characteristics of the copolyamides are substantially affected by chromophore fragments at a content of 10 mol %, while the mechanical properties of the films are independent of the chemical structures of chromophores incorporated into polyamide chains.

Star-thiophene derivatives with a silicon atom as the branching center were investigated by absorption spectroscopy and electro-optical Kerr effect in solutions at variations in a number and chemical structure of branches. The star-shaped oligomers were compared with dendritic analogues containing silicon atoms at the points of branching. It is shown that thiophene-containing moieties determine both spectral and electrooptical properties of the molecules. Molecular parameters of the star-shaped oligomers of various structure vary identically with increasing the number of branches. The absorption of star-shaped oligomers is additive due to the autonomy of the absorption of radiation by the separate branches. For dendritic molecules the additive nature of the absorption is kept, but their electro-optical properties are independent of a generation number. It was shown that the latter is a consequence of the manifestation by dendrimers of deformation flexibility, which is not peculiar to the starshaped derivatives.

Polydialkoxyphosphazenes with partially fluorinated side substituents of different lengths in dioxane and ethyl acetate are studied via the methods of the equilibrium electro-optic Kerr effect, isothermal translational diffusion, and viscosimetry. It is experimentally found that the magnitude and sign of the Kerr constant depend on the length of the side substituents. The observed dependence is explained by the changes in the optical polarizability tensor and the angle between the direction of the permanent dipole moment and the primary axis of optical polarizability of the monomer unit of these macromolecules with an increase in the number of carbon atoms in the chains of alkoxy substituents attached to phosphorus. It is shown that fluorinated polydialkoxyphosphazenes are comblike polymers with high equilibrium skeletal rigidity and non-coincident principal directions of the optical polarizability and dielectric polarizability of the monomer unit.

Six samples of poly(2-deoxy-2-methacryloylamino-D-glucose) were prepared by free-radical polymerization of the monomer. The molecular properties of the homologous series obtained were studied in three solvents, 0.2 M NaCl, 0.1 M Na2SO4, and salt-free water, by viscometry and static and dynamic light scattering. The Mark-Kuhn-Houwink relationships were obtained. The poly(vinyl saccharide) studied, despite the presence of bulky pendant substituents, is a typical flexible-chain polymer with the Kuhn segment length of 20 ± 3 A. In aqueous salt systems, poly(2-deoxy-2-methacryloylamino-D-glucose), which is not a polyelectrolyte, nevertheless demonstrates the dependence of the hydrodynamic size of the molecules on the solvent composition. The SO42− ions make the polymer molecules more compact, whereas Cl− ions present in aqueous solution lead to its expanding. Salt additions affect the thermodynamic quality of the polymer-solvent system.

Molecular properties of poly(dialkoxyphosphazene) (PDAOP) series with the aliphatic side-chains contained 3, 4, 6, and 7 carbon atoms were investigated in dilute benzene solutions by techniques of electro-optical Kerr effect and dynamo-optical Maxwell effect, and by dielectric spectroscopy. The sign inversion of Kerr effect and Maxwell effect in PDAOP solutions from positive to negative was detected at the side-chain length range of 5–6 carbon atoms. These phenomena were explained by the strong dependence of anisotropy of optical polarizability of PDAOP monomeric unit on chemical structure and change of its sign at the indicated side-chain lengths. It was demonstrated that PDAOPs possess a critical side-chain-length interval at which their physical properties, depending on the intramolecular ordering, display a singularity. It was also shown that the studied PDAOP samples are not flexible-chain polymers. They are characterized by Kuhn segment 47–65 A, the value of which increases with the elongation of aliphatic side-chain. Dielectric properties of PDAOP were correlated to the properties of the macromolecules with manifestation of kinetic rigidity under a treatment of electric field.

International audience; The four first generations of dendrigraft poly-L-lysine have been studied in dimethylformamide (aprotic solvent) and in 0.2 M NaCl aqueous solutions by isothermal translation diffusion, 1H NMR and viscometry methods. The relationships between diffusion coefficient, intrinsic viscosity and molar mass have been determined for dendrigraft poly-L-lysines, and the scaling index values have been compared to classical trifunctional dendrimers. Dendrimers and dendrigraft poly-L-lysines exhibited similitudes in their hydrodynamic behaviors. Nevertheless, dendrigraft poly-L-lysines displayed a specific behavior in solution. In contrast to dendrimers, a significant change of hydrodynamic dimension of dendrigraft poly-L-lysines according to the nature of the solvent has been observed. In aprotic solvent, the dendrigraft poly-L-lysine dimensions are about two times lower than in aqueous media (i.e., the hydrodynamic volume is contracted by a factor 8 in dimethylformamide), revealing the softness of dendrigraft poly-L-lysine compared to classical trifunctional dendrimers.

A number of consecutive generations of bithiophenesilane dendrimers and their precursors are studied by the methods of the equilibrium electro-optical Kerr effect, dielectric polarization, and absorption spectroscopy in dilute toluene solutions. It is shown that the molecules of hybrid dendrimers containing bithiophene fragments covalently linked via silicon atoms are not kinetically rigid and feature the small-scale mechanism of interaction with external electric fields. A tris(bithiophene)methylsilane fragment is found to be the subunit responsible for the electro-optical and optical spectral properties of the above hybrid dendrimers. It is revealed that the polarization of bithiophensilane dendrimers predominantly shows the deformation pattern.

Polyamides containing main-chain cyanine chromophores are synthesized, and their molecular, nonlinear optical, and mechanical properties are studied. It is shown that the Kerr electro-optical effect in polymer solutions is determined by the rigidity of polymer chains and that the nonlinear optical properties are dependent only on the chromophore content.

A study of the viscometric and dynamooptical (flow birefringence) properties of cellulose samples in mixtures of 1-alkyl-3-methylimidazolium-based ionic liquids with pyridine was carried out. It was established that the mixtures provide stable molecular dispersed cellulose solutions which are suitable for the determination of the characteristics of the dissolved macromolecules. The viscous and dynamooptical properties of cellulose in ionic liquid/pyridine mixtures, cadoxen (CdO/ethylenediamine), and in cadoxen/water at low solute concentrations were compared, and the behavior of cellulose in these solvents was discussed. It was found that the values of the refractive index of 1-alkyl-3methylimidazolium-based ionic liquid/pyridine mixtures are close to the refractive index of cellulose in their media. The extremely low refractive index increment (|dn/dc| = (0.004 ± 0.001) cm3 g−1) for cellulose in 1-ethyl-3-methylimidazolium diethylphosphate and pyridine ([EMIM]Et2PO4/pyridine (1:1)) allowed to confirm that the cellulose monomer unit is not optically isotropic and is characterized by a small in value and positive in sign anisotropy of polarizability (� a = +1.0 × 10 −25 cm 3

As shown by hydrodynamic, electrooptical, and computer-simulation studies, film-forming addition silicon-substituted polynorbornene and silicon-substituted poly(1-trimethylsilyl-1-propyne), which have close gas-permeability parameters, possess similar conformational properties of chains. The molecules of the these polymers are characterized by a heterogeneous microstructure due to energetically favorable spiralization of regular sequences of monomer units with the interrelated linear sizes of helical fragments and the equilibrium rigidity of chains. Despite different chemical structures, both polymers have the statistical Kuhn segment A = (44–47) × 10−10 m and a much smaller ((10–15) × 10−10 m) kinetic fragment freely orienting under application of an electric field. The hydrodynamic and electrooptical properties of silicon-substituted polynorbornenes synthesized from the same monomer (5-trimethylsilyl-2-norbornene) via addition and metathesis mechanisms are compared. It is found that there is a significant difference in the conformational characteristics of addition and metathesis analogs. This finding gives insight into the earlier observed difference in the properties of films based on these polymers.

Structure-properties relations of liquid crystalline fullerene-containing poly(aryl ester)/poly(benzyl ether) dendritic compounds with variation of C60 linkage type have been analyzed based on experimental data on their total polarity and electro–optical Kerr effect in benzene solutions. There was established that fulleropyrrolidine as the core of dendrimer strongly restricts rotational freedom of dendrons, in contrast to methanofullerene. A conclusion that not only terminal mesogenic groups and dendrons' generation number, but a manner of C60 incorporation into the dendritic matrix also influences on the mesomorphic behavior of these multicomponent hybrid-type liquid crystalline compounds had been made.

Seven polynorbornene samples containing trimethylsilyl side groups that were prepared by the addition polymerization of 5-trimethylsilyl-2-norbornene in the presence of catalytic systems (π-C5H9NiCl)2-methylaluminoxane and nickel naphthenate-methylaluminoxane have been studied by translational isothermal diffusion and viscometry. The molecular masses of the polymer samples are measured. Kuhn-Mark-Houwink equations for diffusion coefficient D and intrinsic viscosity [η] are determined in toluene at 25°C: D = 6.94 × 10−4M−0.61 and [η] = 1.53 × 10−3M0.82. The equilibrium rigidity of polymers chains is estimated as A = 47 ± 9 A. The conformational features of the silicon-containing polynorbornene are analyzed by the PM3 quantumchemical semiempirical method on the basis of simulation of its decamer chain fragments. In terms of microstructure and equilibrium rigidity, the above-described addition poly(trimethylsilylnorbornene) is close to poly(trimethylsilylpropyne) synthesized using niobium pentachloride as a catalyst. This finding explains similar membrane gas-separation properties of these polymers.

Experimental results on the study of electro‐optical, dielectric and hydrodynamic solution properties of 6‐arm polystyrene stars A6C60(PS)6 with a variable structure of low molecular addend, A, are reported. Strong dielectric polarization of A6C60(PS)6 have been detected in external electric fields of radio frequency range and explained by intermolecular long lifetime charge‐separated state of highly symmetric fullere adducts situated at the central part of polystyrene stars.

Janus-type liquid−crystalline fullerodendrimers were synthesized via the 1,3-dipolar cycloaddtition of two mesomorphic dendrons and C60. By assembling poly(aryl ester) dendrons functionalized with cyanobiphenyl groups, displaying lamellar mesomorphism, with poly(benzyl ether) dendrons carrying alkyl chains, which display columnar mesomorphism, we could tailor by design the liquid−crystalline properties of the title compounds as a function of each dendron size. The liquid−crystalline properties were examined by polarized optical microscopy, differential scanning calorimetry, and X-ray diffraction. Depending on the dendrimer generations, smectic (SmC and/or SmA phases) or columnar (Colr-c2mm or Colr-p2gg phases) mesomorphism was obtained. The supramolecular organization is governed by (1) the adequacy of the cross-sectional area of the dendrons, (2) the microsegregation of the dendrimer, (3) the deformation of the dendritic core, and (4) the dipolar interactions between the cyanobiphenyl groups. Comparison of the mesomorphic properties of two fullerodendrimers with those of model compounds (fullerene-free analogues) indicated that the C60 unit does not influence the type of mesophase that is formed. Molecular properties determined in solution (permanent dipole moment, specific dielectric polarization, molar Kerr constant) confirm that microsegregation persists in solution and strengthen the models proposed for the structure of the mesophases.

The molecular mass and hydrodynamic dimensions of molecules of two fullerene-containing polymers which differ in the preparation procedure and the mode of fullerene C60 binding were determined by means of static and dynamic light scattering and transport techniques (diffusion, sedimentation, gel permeation chromatography). It was established that the molecular masses of polymeric C60 derivatives determined by means of static light scattering are substantially above those measured by means of the transport techniques. Using as an example a polystyrene specimen containing 6.2 wt % C60 prepared according to the widespread technique of solvent evaporation from a mutual fullerene and polymer solution, it was shown that the multicomponent nature, the compositional inhomogeneity, and a lack of coincidence in the signs of refractive index increments for structurally different components of fullerene-containing polymers may cause anomalies in the intensity of light scattering by solutions of these compounds.

The molecular properties and composition of fullerene-containing polystyrenes prepared through evaporation of solvent from the combined solution of a polymer and C60 in benzene have been studied by viscometry, translational isothermal diffusion, GPC, UV spectroscopy, and electrooptical Kerr effect measurements. With this procedure of C60 introduction into the polymer, a partial depolymerization of the parent polystyrene takes place. It has been shown that the composites contain fullerene in two forms: a smaller part of C60 is bound to macromolecules, while a larger part of C60 is incorporated into the composition of low-molecularmass adducts—the products arising from the interaction of fullerene with fullerene-induced depolymerized polystyrene.

The study is devoted to estimation of the effect of quaternization on the molecular properties of polysaccharide chitosan. Solution properties of quaternized chitosan derivative, N-[(2-hydroxy-3-trimethylammonium)propyl]chitosan, have been studied in comparison with the initial chitosan in 0.33М СН3СООН + 0.2М CH3СООNa. The averaged quaternization degree of the modified samples was (90 ± 5) %. Hydrodynamics methods, translation isothermal diffusion and viscometry, and static/dynamic light scattering were applied for characterization of two homologues series of chitosans. The equilibrium chain rigidity value and Mark–Kuhn–Houwink relationships for intrinsic viscosity and diffusion coefficient have been received for the both polysaccharides at pH 3.54 and high ionic strength value. A change of thermodynamic conditions in the same solvent was detected for the modified chitosan in relation to initial analog. Even though the side substituents length is longer for the modified polysaccharide, the hydrodynamic dimension of its molecules could be smaller than initial polysaccharide of the same polymerization degree due to nonequivalent contributions of thermodynamic/electrostatic interactions to the total chain rigidity. The hydrodynamic behavior of quaternized chitosan in 0.33М СН3СООН + 0.2М CH3СООNa has been compared to its behavior in 0.2 M NaCl. The influence of the secondary amino group protonation on hydrodynamic properties of modified chitosan molecules was detected at neutral pH. Solution properties of quaternized chitosan in 0.2 M NaCl were identified as the concentration dependent.

Study of the content of composite polystyrene‐fullerene samples prepared from solution by the solvent evaporation method have been performed with the size exclusion chromatography, translation diffusion, viscometry and electro‐optical Kerr effect techniques. It was established that polystyrene interacts with fullerene C60 in benzene without any special treatment at room temperature just after the mixing of polymer and fullerene solutions. The product of this interaction contains initial polystyrene and low molecular fullerene adducts that appear as a result of depolymerization of a significant part (up to 40 wt.%) of polymer chains.

The behavior of molecules of a star-shaped six-arm polystyrene with a covalently bound fullerene C60 as a branching center was studied by viscometry and by measuring the electrooptical Kerr effect and the dielectric polarization in solutions. It was shown that polarization and electrooptical characteristics of a fullerene-containing polystyrene (C60 ∼ 3 wt %) differ by an order of magnitude or even greater from the corresponding characteristics of the parent polymer. A comparison of the above properties with the analogous characteristics of the model hexaadduct (the products of reaction between octyllithium and fullerene C60) demonstrated that a difference in the behavior of the star-shaped polystyrene and its parent analog is associated with the structural features of the branching center, among which is the occurrence of six proton addends that are bonded rather weakly to the fullerene cage in the hexaadducts under study.

Star‐like fullerene C60 derivatives with different branch number, synthesized by the reaction of fullerene with poly(vinylpyrrolydone) (PVP) macromolecules bearing the terminal amino‐groups, were investigated in solution by the viscometry, dielectric, and electrooptical Kerr‐effect methods in comparison with the ordinary linear PVPs of the same molecular mass. It was shown that covalent linkage of branches to fullerene through amino‐groups leads to appearance of a polar and optically anisotropic nanoparticle (amine‐substituted C60) in the center of the coil of star‐like polymers that radically changes dielectric and electrooptical properties of the initial polymer. Effect of fullerene on the dimension of polymer coil had been detected also.

The water‐soluble composites with fullerene content up to 5 wt% based on poly‐(N‐vinylpyrrolydone) (PVP) were obtained. The higher fullerene content is achieved by means of introducing tetraphenylporphyrine (TPP) and KBr into composites. The synthesis includes the formation of C60–TPP complex and its further interaction with polymer. The formation of C60–TPP complex was confirmed by 13C NMR, SANS, and translational diffusion. The hydrodynamic and electrooptical studies of C60–TPP–PVP complexes indicate the higher symmetry of the polymer coil in the complex as compared to PVP. The C60–PVP–KBr composites were also obtained by the solid state interaction under vacuum, KBr promoting the destruction of fullerene aggregates.

Novel fullerene C60 containing liquid crystalline dendrimers and hemi‐dendrimers have been characterized by the method of electro‐optical Kerr effect and determination of the permanent dipole moment, sensitive to the molecular polar ordering and anisotropy of polarizability, and by hydrodynamic methods in solution. An influence of the covalently bonded fullerene on the polarity, electro‐optical, and viscometric properties of fullerene derivatives have been detected, analyzed, and concluded that fullerene produces a change in the original ordering in dendritic molecules, which mainly resulted in correction of the shape asymmetry of these molecules as a whole.

Mesomorphic fullerene derivatives of dendritic structure were studied in solutions by the method of electrooptical Kerr effect, hydrodynamic methods (translation diffusion and viscometry) and by the method of dielectric polarization of the solutions. The influence of covalently bonded fullerene C 60 on the polarity, electrooptical and hydrodynamic properties of fullerene containing samples was observed in comparison with fullerene free analogues. The change of molecular form asymmetry for fullerene-containing dendritic compounds was detected. It was shown that properties of the dendritic molecules depend on fullerene position in their structure and that hemi-dendrimers are more sensitive to the incorporation of fullerene than dendrimers.

Aggregation of fullerene C 60 with the solvent molecules in N -methylpyrrolidone solutions have been studied by the spectral and electrooptical methods. The time evolution of electronic absorption and photoluminescence spectra of solutions at the various initial concentrations of the solute has shown that the aggregation process is strongly concentration dependent. A comparison of spectral data with the electrooptical properties of solutions made it possible to conclude that at the concentration range −2 g cm −3 , a process of complex formation between C 60 and N -methylpyrrolidone molecules takes place.

The donor-acceptor complexes of the C60 fullerene with cycle-containing polymers, namely, poly(2,6-dimethyl-1,4-phenylene oxide) (PPhO) and poly(N-vinylpyrrolidone) (PVP), are studied. A comparative analysis of the hydrodynamic and electrooptical properties of the initial polymers and their complexes with C60 in solutions demonstrates that the C60 fullerene has a restructuring effect on the polymer macromolecule, thus decreasing the degree of asymmetry of the macromolecular structure.

The hydrodynamic and electro-optical (Kerr effect) properties of two side-chain liquid crystalline (SCLC) polymers have been investigated in benzene and chloroform solution. The polymers are unique in structure and have been prepared using the Baylis-Hillman methodology. The polymers contain (a) a polar group (CN or COCH 3 ) along the polymer backbone and (b) a hydroxyl group on the spacer group which is adjacent to the point of attachment of the spacer/mesogenic side groups to the polymer backbone. Molecular dimensions and the Kerr constants were determined for two SCLC polymers and for three low molar mass materials, the n-alkoxycyanobiphenyls (nOCB), which are structurally similar to the side chain used in the SCLC polymers. These results are discussed in relation to the chemical structure and dipole moment of the monomer unit. Dielectric and electro-optical properties of the SCLC polymer containing the -CN group along the polymer backbone were found to be similar to the properties of the nOCB compounds. The difference in the mesogenic side-chain mobility of the polymers was related to the dipole-dipole interactions of the polar groups along the polymer backbone.

Flow birefringence of dextran solutions in dimethylsulphoxide was studied and the intrinsic optical anisotropy (α 1 -α 2 ) of its chains was determined to be +12.5×10 −25 cm 3 . The dependence of birefringence in dextran films of different thickness on the angle of incidence of polarized light was then studied and the surface birefringence of the film was determined. The dependence of surface birefringence on film thickness has made it possible to determine the effective thickness of the anisotropic near-surface layer, while the comparison of the surface birefringence with the value of (α 1 -α 2 ) enabled the estimation of the orientation of the molecular fragments with respect to the film surface.

Maxwell effect and Kerr effect techniques were used to study the intramolecular axial ordering of anisotropic side groups of an isolated macromolecule in solution. Three comb-like polymers with a methacrylic main chain were investigated. The side chains contain aliphatic spacers separating the mesogenic fragments R from the backbone. R contains two or three rhenylene rings with ester linking groups and cyano end groups. Fragments R are attached to the side chains, by the end or middle-point, through the para- or ortho-phenylene ring. The main-chain conformation in solution was identified to assess the hydrodynamic data using the Gaussian coil approximation. The optical anisotropy of the macromolecule segment was determined and related to the monomer unit structure. The specific Kerr constant obtained in diluted benzene solution of polymer was compared with those of low molecular weight analogues of the polymer mesogenic groups. The mobility and intramolecular ordering of the mesogenic groups in the isolated macromolecules are discussed. These properties are compared with those of comb-like polymers with another type of attachment of mesogenic groups, and with another (siloxane) chemical structure of the backbone chain. The differences in restrictions of side-chain mobility due to the backbone linkage in different types of comb-like polymers are also discussed.