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PH-responsive micelles that were formed by asymmetric MOPEO-b-PAAc diblock copolymers with chemically complementary methoxypoly(ethylene oxide)/poly(acrylic acid) blocks were used as nanocarriers to study the encapsulation/release processes of the poorly soluble homologue of α-tocopheryl acetate, known as the analogue of Vitamin E. These nanocarriers showed the high encapsulation degree of α-TOCA (near 100%) which did not depend on the encapsulation pathway (in situ or ex situ). The effect of various factors such as the time, the solution pH and the addition of NaCl on the state and behavior of α-TOCA solutions, micellar dispersions of the diblock copolymer and their micellar compositions were studied and discussed. A methodology for correctly determining the degree of α-TOCA encapsulation and release by the copolymer micelles was described. A gradual release of α-TOCA from micellar nanocarriers in the dialysis of micellar compositions against deionized water and a significant decrease in α-TOCA release in "physiological solution" and, especially, in water with pH =9 was established. [ABSTRACT FROM AUTHOR]

Novel film polymeric composites based on the non-photoconducting polyvinyl butyral with heterometallic complexes (NH4)4n{[Cu(en)(H2O)][P2Mo5O23]}n·3.5nH2O (1) and (NH4)2n{[Cu(en)2][Cu(en)(H2O)][P2Mo5O23]}n·3nH2O (2) [en = ethylenediamine] have been prepared. Both compounds are similar and contain Strandberg anions [P2Mo5O23]6– linked to Cu-diamine species. The main structural difference between complexes is the presence of additional bridging [Cu(en)2] fragments in 2, which provide an extra connectivity between the neighboring polyoxometalates. However, the different saturations and relaxation times of the photoresponse, as well as different activation energies, are shown. The variability of the photoconducting properties can be explained by the influence of a chain rigidity on the transport of non-equilibrium charge carriers. [ABSTRACT FROM AUTHOR]

In binary polymeric compositions the polymer-polymer interaction was significantly affected by low molecular weight substance (LMWS) localized at the interphase layer (IPL). In this case LMWS can serve as compatibilizer of system. The systems "copolymer AB – homopolymer B", were B – is nonpolar component,are suitable models to study the redistribution processes of intermolecular forces at the polymer-polymer interfaces. It is the compositions with non-polar components form the developed IPL. It is known that mixtures that contain polystyrene component can form structures with the content of the IPL around ∼20%. On the other hand, interphase layers formed by nonpolar polymers are not strong. There is a problem to increase the intensity of intermolecular interaction in these layers. It is known that the styrene-acrylonitrile copolymers (SAN) - polystyrene (PS) systems (SAN-PS) are systems with limited compatibility between components. Interaction in the interphase layer of such mixtures is provided by the π-π electron conjugation of the phenyl rings of SAN and PS. But the phenyl groups of macromolecule cannot effectively interact with the corresponding groups of other macromolecule, also they cannot show distinct coplanarity that are necessary for the formation of π-π complexes. In our opinion, there is a possibility of coplanarity correction due to addition of the third component - LMWS, in particular the low molecular weight arene [1] [ABSTRACT FROM AUTHOR]

The novel photosemiconducting magneto-sensitive thin film structures based on carbazole-containing oligomer doped by stable organic radical 2,2-diphenyl-1-picrylhydrazyl as the photoconductivity sensitizer have been prepared. Their spectral, photoconductive, photovoltaic and information properties were investigated. It was shown, that the investigated composites exhibit photoconductivity and photovoltaic properties under illumination by light from the respective stable radical absorption region. The features of the photoconductive and photovoltaic properties of the investigated composites, as well as the possible mechanisms of the photovoltaic effect and charge carriers photogeneration were discussed. It was shown that the prepared films can be used as reversible holographic recording media. [ABSTRACT FROM AUTHOR]

The novel oligomeric thin film structures with photochromic properties were obtained. They based on carbazole-containing oligomer as a matrix and azo-dye 4-((4-nitrophenyl)diazenyl)phenol as a photosensitive additive. Spectral, photoconductive, photovoltaic and information properties of films were investigated. It was shown, that all investigated film composites exhibit photoconductive and photovoltaic properties under light irradiation correspond to the azo-dye absorption region. The features of the photoconductive and photovoltaic properties of the investigated compositions, as well as the possible mechanisms of the photovoltaic effect and charge carriers photogeneration, were discussed. It was shown that the prepared composites can be used as reversible recording media. [ABSTRACT FROM AUTHOR]

The films of polymeric composites based on non-photoconducting polyvinyl alcohol and polystyrene doped by various concentration of xanthene and triarylmethane type dyes have been prepared. Their photophysical, electrical, and spectral properties have been investigated. It was shown, that all studied composite films exhibit photovoltaic properties and anomalous negative photoconductivity effect. The diffusion nature of observed photovoltaic effect was established. The features of photovoltaic effect and photoconductivity, as well as the possible negative photoconductivity mechanism are discussed. [ABSTRACT FROM PUBLISHER]

The new heterostructures comprising a squarylium dye (SQ) film deposited onto a oligo-N-epoxypropylcarbazole (OGC) film have been created, and their photoconducting, photodielectric, and photovoltaic properties have been studied. The OGC/SQ heterostructures exhibit the photodiode properties. It is concluded that the p–n junction in these heterostructures is ensured by the hole character of conductivity in the oligomer and the bipolar conductivity of the deposited dye film. [ABSTRACT FROM PUBLISHER]

Features of the electrical conductivity and the photoconductivity of polyvinylbutyral films containing silicon nanoparticles and similar films doped with cationic and anionic polymethine dyes are studied. Sensitization of the photoelectric effect by dyes with various ionicities in films is explained by the possible photogeneration of holes and electrons from dye molecules and the intrinsic bipolar conductivity of silicon nanoparticles. It is assumed that the electronic conductivity in silicon nanoparticles is higher as compared with that in nanoparticles with p-type conductivity. [ABSTRACT FROM AUTHOR]

Photophysical and information properties of the holographic recording media (HRM) based on films of ferrocenyl-containing siloxane oligomer, glycidylcarbazole-butylglycidylic ether cooligomer, ferrocenemethylated oligoglycidylcarbazole, and cooligomer of o-carboxybenzoilferrocene glycidylic ether doped with squarilic dye and(or) with merocyanine dye based on ferrocene and tetranitrofluorene are investigated. It is found that the holographic sensitivity is absent for the media based on ferrocenyl-containing siloxane oligomer, and that the holographic sensitivity is present for the films based on glycidylcarbazole. It has been found that the holographic sensitivity and the photoconductivity of the media based on glycidylcarbazole cooligomers increases with the ferrocene content. This effect has been explained by the influence of iron ions on the rate of singlet-triplet conversion in photogenerated pairs of charges. [ABSTRACT FROM AUTHOR]

Methacrylic azopolymers with different spacer lengths in side chains have been synthesized. The spectra and kinetics of the electrooptic effect which arises in azopolymer films after their irradiation by linearly polarized light are investigated. The photo-induced optical anisotropy in the films appears due to a change of the concentration ratio of trans- and cis-isomers of azobenzene fragments. This explains the nature of the electrooptic effect. Owing to a mobility increment of azobenzene fragments by means of the spacer extension, the electrooptic effect becomes more pronounced, and its relaxation time decreases. [ABSTRACT FROM AUTHOR]

The films of polymeric composites based on a copolymer of acrylonitrile with styrene (SAN) with the low concentration of an anionic (AD) and (or) cationic polymethine dye (CD) are obtained. The increase of the electroconductivity of SAN films, that contained dye additives, is detected by comparison with the electroconductivity of pure SAN films. The photoconductivity of SAN films with cationic dye additions wasn't found out on the irradiation in the visible region of light. On the contrary, the photoconductivity of the SAN films with AD addition was detected on the photoexcitation in the region of dye absorption. Some features of the photoconductivity and electroconductivity of such composites doped with AD are investigated. [ABSTRACT FROM AUTHOR]

The effect of the deposition of layers "polymer-dye" with different types of conductivity on the surface photovoltage (V) of CuInS2 (CIS) has been studied. The influence of composite layers depends on the molecular structure of a polymer, the type of conductivity and photosensitivity of a dye. The photovoltage growth mainly in the region of strong absorption of a dye was observed after the deposition of the composite consisted of the p-type polymethine dye and the carbazole I-contained polymer on the CIS surface. The spectral dependence of this composite in the low-absorption region is only weakly changed. On the contrary, the deposition of the composite consisted of the perylene n-type dye in polymer on CIS leads to a decrease of V, especially in the dye absorption region. A decrease of the short-wavelength slope is caused by the presence of surface recombination centers in CIS films. The above-mentioned results can be explained by the presence of a few concurrent processes, the efficiency of which strongly depends on the used polymer and the type of conductivity of a dye. [ABSTRACT FROM AUTHOR]

The effect of amplification of photoluminescence of cationic polymethine dyes in the photoconducting polymer films of poly-N-epoxypropylcarbazole, poly-N-vinylcarbazole in comparison with non-photoconducting polymers - polyethylene, polyvinyl alcohol, polyvinylbutyral, and polystyrene were discovered. Such effect is absent for anionic and neutral dyes. The amplification PL increases with a decrease of wave length of excitation light and increase of energy of the highest occupied molecular orbital of a dye. This effect correlates with growth of a photoconductivity, a quenching of PL and a recombination luminescence by an external electric field. The amplification PL is interpreted by the contribution to it of a recombination luminescence of charges in photogenerated electron-hole pairs. The features of a structure PEPC and PVC, favouring to formation and recombination of these pairs are analysed. [ABSTRACT FROM PUBLISHER]

The effect of amplification of photoluminescence of cationic polymethine dyes in the photoconducting polymer films of poly-N-epoxypropylcarbazole, poly-N-vinylcarbazole in comparison with non-photoconducting polymers - polyethylene, polyvinyl alcohol, polyvinylbutyral, and polystyrene were discovered. Such effect is absent for anionic and neutral dyes. The amplification PL increases with a decrease of wave length of excitation light and increase of energy of the highest occupied molecular orbital of a dye. This effect correlates with growth of a photoconductivity, a quenching of PL and a recombination luminescence by an external electric field. The amplification PL is interpreted by the contribution to it of a recombination luminescence of charges in photogenerated electron-hole pairs. The features of a structure PEPC and PVC, favouring to formation and recombination of these pairs are analysed. [ABSTRACT FROM AUTHOR]