Unusual quasi-two-dimensional crystals of a regular triangular shape, self-formed in the process of obtaining a coordination polymer based on phenazine and silver, are described and studied. X-ray diffraction studies were carried out, the interplanar distance was determined, and the spectra of Raman scattering were obtained. A mechanism is proposed that can cause the appearance of triangular crystals from nuclei of hexagonal symmetry.

Electrically conductive composite textile and textile combining electrically conductive and magnetic properties have been obtained on the basis of biocompatible non-toxic materials: commercial non-woven textiles, electrically conductive polypyrrole and magnetite (Fe3O4). The composite textile has been formed from two-layer fibers, where the fibers of the original textile are coated with a polypyrrole shell, and the textile combining electrically conductive and magnetic properties have had a three-layer structure, where magnetite particles are deposited on top of the polypyrrole shell. The composite textiles have retained the structure of the original fabric with free interfiber space: the specific surface area of the materials and their mechanical properties have been similar in value. The composition of materials, their electrically conductive, magnetic, and redox properties have been investigated. The interaction of the composite textile and the textile combining electrically conductive and magnetic properties with electromagnetic radiation in the frequency range of 4–8 GHz have been investigated in comparison with a commercial radio-absorbing material based on carbonyl iron.

Conducting composite based on biocompatible chitosan and single wall carbon nanotubes was used as a matrix for electrical stimulation of human fibroblasts. Parameters of ionic and electronic currents passing through the matrix upon applying cyclic potentials (±100 mV) were studied; the scaffold demonstrated high stability in the course of prolonged electric cycling. It was shown that preliminary electrical stimulation facilitated proliferative activity of human dermal fibroblasts in comparison to that of intact cells. Keywords: chitosan/carbon nanotube composite, electrical stimulation, dermal fibroblasts.

Electroconductive scaffolds of different shape for tissue engineering have been obtained on the basis of two biocompatible polymers: polylactide and polypyrrole. The composite scaffolds have been based on porous permeable films or tubes of polylactides prepared via electrospinning. A layer of electroconductive polypyrrole has been applied at the developed surface of the scaffolds consisting of the chaotically interwoven fibers of micron-scale thickness. The structure of the tissue engineering scaffolds as well as their mechanical, redox, and electroconductive properties have been investigated. It has been found that the scaffolds are stable during electrical stimulation via prolonged application of the cyclic potentials.

The paper presents the results of an experimental study of the electric conductivity and thermoelectric properties of a new coordination polymer (CP) based on phenazine ligands (Phz) and silver (Ag) synthesized by a one-step method. This method produces phenazine by oxidative dimerization of aniline under the action of AgNO3 followed by release of metal nanoparticles and subsequent self-organization of Phz with excess AgNO3 into the CP. The used method of the Phz-Ag synthesis was found to make possible obtaining CP with conductivity of about 1300 S/cm commensurable with the modern record value for CPs. The obtained experimental data led to the conclusion that the studied CP Phz-Ag possesses a metallic type of conductivity. A physical mechanism of forming this property was put forward.

In this work, an electrically conductive composite based on thermoplastic polyimide and graphene was obtained and used as a bioelectrode for electrical stimulation of human dermal fibroblasts. The values of the electrical conductivity of the obtained composite films varied from 10−15 to 102 S/m with increasing graphene content (from 0 to 5.0 wt.%). The characteristics of ionic and electronic currents flowing through the matrix with the superposition of cyclic potentials ± 100 mV were studied. The high stability of the composite was established during prolonged cycling (130 h) in an electric field with a frequency of 0.016 Hz. It was established that the composite films based on polyimide and graphene have good biocompatibility and are not toxic to fibroblast cells. It was shown that preliminary electrical stimulation increases the proliferative activity of human dermal fibroblasts in comparison with intact cells. It is revealed that an electric field with a strength E = 0.02–0.04 V/m applied to the polyimide films containing 0.5–3.0 wt.% of the graphene nanoparticles activates cellular processes (adhesion, proliferation).

Unusual quasi-two-dimensional crystals of a regular triangular shape, self-formed in the process of obtaining a coordination polymer based on phenazine and silver, are described and studied. X-ray diffraction studies were carried out, the interplanar distance was determined, and the spectra of Raman scattering were obtained. A mechanism is proposed that can cause the appearance of triangular crystals from nuclei of hexagonal symmetry.

Conducting composite based on biocompatible chitosan and single wall carbon nanotubes was used as a matrix for electrical stimulation of human fibroblasts. Parameters of ionic and electronic currents passing through the matrix upon applying cyclic potentials (±100 mV) were studied; the scaffold demonstrated high stability in the course of prolonged electric cycling. It was shown that preliminary electrical stimulation facilitated proliferative activity of human dermal fibroblasts in comparison to that of intact cells.

It was demonstrated that conducting polymers can be used in development of bioactive matrices for tissue engineering. The most promising conducting polymer for biomedical applications is polypyrrole. Due to a number of useful properties, polypyrrole can be used in designing “smart” biologically active materials. In order to improve mechanical properties of the composite matrices, aliphatic copolyamide was used. Thin polymeric films were obtained from solution of this copolyamide; the solution was also used in preparation of non-woven fibrous mats by electrospinning. Copolyamide films were modified with pyrrole in the process of its oxidative polymerization to give the desired composite matrices. The obtained samples demonstrated suitable performance characteristics and a sufficient conductivity level for cell technologies. In vitro experiments showed that the matrices based on copolyamide and polypyrrole provide good survivability, adhesion and proliferation of human dermal fibroblasts.

The conducting film material intended for research in the field of cell technology is obtained on the basis of two biocompatible polymers—aliphatic copolyamide and polypyrrole. The material consists of hybrid nanofibers having the core–shell structure. The film is formed by copolyamide microfibers that are obtained by electrospinning and coated with a polypyrrole nanolayer. Studies show that the material is stable and does not change its characteristics when stored both in air and in aqueous media. The hybrid fiber film has a high porosity, good water wettability, and a sufficient level of stress–strain characteristics. The resistance of the material is 300–600 Ω/sq, which allows its use for the electrical stimulation of proliferative activity of cells.

NSG01 industrial atomic force microscope probes were functionalized by the electrically conductive polymer, polyaniline, during in situ oxidative polymerization of aniline at the probe point, which was confirmed by scanning electron microscopy. The quality of the deposited polymer can be controlled by measuring the resonance frequency of the gauge during functionalization. The comparative test of the probes prior to and after functionalization was performed using a TGT01 calibration grate, as well as on a special polyaniline test layer with a complex nanosized morphology in the semicontact mode of surface relief study and the phase contrast mode. Local current spectroscopy showed that the functionalized probe can be converted repeatedly from the conducting to nonconducting state owing to a reversible change in the conductivity of the polymer coating.

Conducting materials based on polypyrrole-modified nanofibers of polylactides of different molecular masses and copolymers of ε-caprolactam (–NH–(CH2)5–CO–) and hexamethylenediamine adipate (–H(CH2)6NHCO(CH2)4CO–) were prepared. As shown by scanning electron microscopy, oxidative polymerization of pyrrole on the polymer nanofiber matrix depends on the nanofib er hydrophilicity. The heterophase synthesis of polypyrrole on the surface of hydrophilic nanofibers of the aliphatic copolyamide allowed uniform coating of the material surface with polypyrrole nanoparticles. The surface resistivity of the composite material was about 0.4 kΩ sq–1.

Using the aniline oxidative polymerization, polyaniline–carbonaceous material composites were synthesized, in which polymer layer at the carbon particle surface forms fibers oriented perpendicularly to the support surface. Conductivity, surface properties, and electrochemical activity of the composites in wide composition range are studied. The composites with fibrous morphology of polymer layer are shown to have much higher electrochemical capacitance than those with dense and homogeneous polyaniline layer.

The films of polyaniline (PANI) on the glass slides with granular morphology were prepared by oxidative polymerization with ammonium peroxydisulfate in strong acidic conditions. The kinetics of polymerization was monitored recording of scanning electron microscopy images of deposit PANI films on glass slides. Statistical analysis of the PANI grain size was successfully applied for characterization of the polymerization process. It was shown that oxidative PANI polymerization could be described as a topochemical process. This allowed us explaining the existence of three phase of process (induction period, acceleration stage and decay) and finding the kinetics parameters of these stages. The model of phenazine nucleates was used to described induction stage. It was shown that phenazine nucleation process can be described kinetically as zero-order reaction. The acceleration stage of PANI polymerization was connected with increase of PANI grain surface during reaction and the mechanism of this acceleration was discussed. The decay stage of process was attributed with formation fuse loose PANI film with reduced available interphase surface for polymerization process. (C) 2013 Elsevier Ltd. All rights reserved.

The edge luminescence of polyaniline, an organic semiconductor, has been observed for the first time. The bands in the luminescence spectrum correlate in position with the known bands in the absorption spectrum. The experimental data are used to estimate the band gap of the polymer. The nature of the recombination processes is discussed.

Method for deposition of layers of the organic semiconductor polyaniline onto various kinds of supports was developed. The method enables control over the layer thickness and morphology. It is based on formation of a polymeric layer on the support in the course of a heterophase in situ polymerization of aniline. Processes of self-organization of polymer chains on a support and their dependence on the in situ polymerization conditions were studied. Characteristics of polyaniline layers of varied morphology on different kinds of supports were analyzed by electron microscopy, spectroscopy, and conductometry.