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The peculiarities of the structural organization of silver nanoparticles (AgNP) and their antimicrobial properties were studied using the methods of FTIR spectroscopy, X-ray analysis, electron microscopy and the discdiffusion method. In this paper, for the first time, an anionic oligomeric ionic liquid with a hyperbranched structure developed by us was used as a surface stabilizer in the synthesis of AgNP. The synthesis of AgNP was carried out by reducing Ag ions in AgNO3 with trisodium citrate in the presence of this ionic liquid. It was established that there are adsorbed ionic and carbonyl groups on the surface of the formed AgNP, and the formation of complexes between the ionic liquid and silver ions was revealed. According to electron microscopy, the size of the synthesized nanoparticles varies from 8 to 22 nm, with an average value of 14.2 nm. The synthesized silver nanoparticles showed a very high antimicrobial activity against C. albicans fungi, while the width of the inhibition zone (d) was 34 mm. In addition, the powder of AgNP shows a very high activity against gram-positive bacteria S. aureus (d = 30 mm) and gram-negative bacteria E. coli (d = 10 mm). [ABSTRACT FROM AUTHOR]

Copyright of Nanosistemi, Nanomateriali, Nanotehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Nano- & Electronic Physics is the property of Sumy State University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The research of electric properties of the systems based on polyethylene glycol and carbon nanotubes (CNT) near-by the percolation threshold is done using the method of impedance spectroscopy. It is set that the percolation threshold for these systems substantially depends on the sizes of nanotubes. It is discovered that with the increase in the CNT diameter, the percolation threshold is increased. The dispersion parameters of nanotubes were calculated using theoretical model. The results of calculations and microphotographs testify to the high level of CNT aggregates in the polymer nano-composites based on polyethylene glycol. [ABSTRACT FROM AUTHOR]

By using impedance spectroscopy and optical microscopy methods the investigation of electrical properties of systems based on polypropylene glycol was conducted. It was shown that adding exfoliated layered fillers to the system shifts percolation threshold to low concentration of nanotubes. Analysis of critical indexes of conductivity for investigated systems has shown that such low values of t (1,19-1,43) mean that the formation of conductive network because of strong interaction between laponite and single nanotubes is not a statistic percolation process and distribution of filler particles is nonuniform. Thus, incorporation of third component leads to significant change of percolation properties of filled system, because of its strong interaction with conductive particles. Moreover, insertion of third component leads to significant enhancement of distribution of nanotubes in the bulk of polymer matrix and can improve a number of properties of system filled with nanosized particles polymers. [ABSTRACT FROM AUTHOR]

Experimental results and theoretical studies of thermophysical characteristics crystalline polyethylene nanocomposites containing from 0.3 to 2.5 wt. % carbon black and nanocomposites containing from 0.2 to 1.5 wt. % carbon nanotubes is done in the article. The fundamentals of the effective medium theory and percolation theory and how they correlate with the experimental data is shown. The features of the structure's influence of polymer composites on their thermal properties is studied. A comparative analysis of the thermal conductivity of the compositions according to the geometry of the filler is done. [ABSTRACT FROM AUTHOR]

The research of the electrical properties of the systems based on polyethylene glycol and carbon nanotubes near-by the percolation threshold is done using the method of impedance spectroscopy. It is established that the percolation threshold for these systems is 0,5%, and critical index t = 1,17. It is discovered that non-conducting polymeric film appears between separate nanotubes. The thickness of the film which is 7-8 Å and its contact resistance which is 3·105 Ohm were derived using theoretical models. This explains a difference in conductivity of pure nanotubes and probed system after the percolation threshold. [ABSTRACT FROM AUTHOR]

It has been studied electrical and optical properties of the systems based on the polypropylene glycol and carbon nanotubes by impedance spectroscopy and spectrophotometry methods. It is shown that conductivity grows and optical permeability decreases with nanotubes content at the system according to the percolation behavior. The concentration dependences of the conductivity and optical permeability have been analyzed within scaling approach. It is shown that optical percolation threshold for this system equals 0,01%. The experimental results have described within critical percolation model. [ABSTRACT FROM AUTHOR]

The investigation of electric and dielectric properties of the systems based on polypropylene glycol and carbon nanotubes, which contain inorganic salt LiClO4 and without salt, was conducted using the method of impedance spectroscopy. It was discovered that these systems show a fractal behavior. The percolation thresholds of the probed systems is determined, it is 0.45% and 0.40%, accordingly. It was set that the processes of charges transfer are described well within the framework of the model of intercluster polarization. For the system PPG-LiClO4- CNT the so-called, "bridge" effect takes place which leads to the decrease of the prcolating threshold. [ABSTRACT FROM AUTHOR]

By method of impedance spectroscopy the dielectric properties of polypropylene glycol with Mw=400 (PPG-400) and carbon nanotubes(CNT) in percolation transition field were investigated. At the defined concentration CNT ~0.45% in the PPG-400/CNT system the percolation threshold was observed and both sharp change of electrical conductance and α-relaxation time was appeared. [ABSTRACT FROM AUTHOR]

Structure and percolative properties of composites based on polyvinyliden fluoride (PVDF) and its mixtures with polyaniline (PANI), doped with p-toluenesulfonic acid (TSA) was investigated by the methods of X-ray analysis, differential scanning calorimetry and impedance spectroscopy. It was shown, that descriptions of such compositions substantially depend on content of PANI-TSA and on the method of their preparation. It was established, that systems PVDF-PANI-TSA show a percolation behavior with low percolation threshold Cc H" 4%. The decrease of the crystallinity of PVDF-PANI-TSA systems specifies the mobility decrease of polymer chains of PVDF in the boundary layer around particles PANI-TSA. The investigated system is incompatible, that results in a segregation PANI-TSA in a separate phase. [ABSTRACT FROM AUTHOR]

The development, structure and properties of polymer electrolytes were discussed in the review. The special attention was spared to the influence of fillers on structural descriptions, electric and thermophysical properties of nanocomposite polymer electrolytes. The data of conductivity and temperatures of transitions for the described systems were cited. [ABSTRACT FROM AUTHOR]

Structure and conductivity of systems based on polyethyleneglycol (PEG), LiClO4 and anisometric nanofillers in bulk and thin films were studied using X-ray scattering and dielectric relaxation spectroscopy methods. It was shown, that structure of the systems based on PEG, substantially depend on the content of the nanofiller and the type of the plate, where the film was formed. It is discovered that the relative degree of crystallinity of PEG/LiClO4 has extreme behavior, which is dependent on the content of the nanofiller. [ABSTRACT FROM AUTHOR]

By using Fuoss-Kraus theory and the conductivity data, we study the ion association in polymer electrolyte based on polyethyleneglycol, lithium perchlorate and carbon nanotubes. We also determine that the filler addition decreases the aggregation in the polymer electrolyte, which leads to the increase in the number of free ions, as well as to the conductivity growth. [ABSTRACT FROM AUTHOR]

Structure and thermal properties of systems based on olygoethyleneglycol and anisometric nanofillers were studied using X-ray scattering and DSC methods. It is shown that structure and thermal properties of the systems based on OEG substantially depend on the nature and content of nanofiller. It is discovered that thermal characteristics has extreme behavior, which is dependent on composition of systems based on OEG. [ABSTRACT FROM AUTHOR]

The relaxation processes and conductivity of polymer electrolytes based on oligoethyleneglycol (OEG) and anisometric nanofillers were studied using dielectric relaxation spectroscopy. It is shown that the levels of conductivity of the systems based on OEG substantially depend on the nature and content of nanofiller. It is discovered that conductivity of direct current has extreme dependence on composition of polymer electrolytes based on OEG. [ABSTRACT FROM AUTHOR]

One-step method of synthesis of sulfonate proton-donor agent of hyperbranched structure was developed. Hybrid organic-inorganic nanostructured proton conducting membranes were synthesized via combination of proton-donor agent with α, ω-dialkoxysilane derivative ofoligooxyethyleneurethaneurea during the sol-gel synthesis. The relationships between the composition, structure and properties of the obtained membranes which are characterized by proton conductivity of 10-5-10-4 S/cm at 100 °C under anhydrous conditions was established. [ABSTRACT FROM AUTHOR]

Hyperbranched polyetherurethanes were synthesized by the reaction of Hyperbranched aliphatic polyeterpolyols of three generation and isocianate forpolymers. Synthesized polymers were characterisated by the method of IK-spectrums, IPS-chromatography, different scanning calorimetric. That were found that the urethanes fragments in the chain lead to the microgeterogenic structure of hyperbranched polymers. [ABSTRACT FROM AUTHOR]

Properties of new film-forming nucleus-fluorinated aromatic polyethers comprising tertiary and quaternary atoms of nitrogen (in the form of salts) have been investigated. Introduction of specified nitrogen atoms into polymers, alongside with change in the aminoalkyl fragment chemical construction, allows to control their mechanical and physico-chemical features in a wide range. Ammonium salts were successfully transformed into polymeric ammonium basis, static ion-exchange capacity of which is not lesser than that of sulfonated fluorocontaining aromatic polyethers. [ABSTRACT FROM AUTHOR]