Search academic texts

Information × Registration Number 0211U005249, 0110U006261 , R & D reports Title Studying of optical properties of nanomaterials on the base of liquid-crystal media with carbon nanotubes and other nanoparticles by the methods of singular optics for assignment and investigation of mechanisms of their interaction with electromagnetic radiation including optical vortices generation, preparation of the methods of nanomaterials complex diagnostics and certification, establishment of time variations of their characteristics. popup.stage_title Head Soskin M.S., Registration Date 12-03-2011 Organization Institute of physics NASU popup.description2 Carried out research into the physical properties (conductivity, microstructure and phase transitions) composite dispersions based on liquid crystal (SC) 5CB (pentyl-4'-tsianobіfenіl) and multiwalled carbon nanotubes (CNTs). We used both the original (a) and modified (m) nanotubes. Their concentrations ranged from 0.025 to 1% by weight. Under the modification of the nanotubes to be understood some degree of mechanical grinding to produce nanotubes with smaller length. Direct microscopic studies of the composites at different concentrations of nanotubes showed the presence of aggregates and the percolation process. Formation of percolation clusters were observed at concentrations of Cp ~ 0.025-0.05% of weights and C = Cp ~ 0.1-0.25% weights for the in-nt, and m-HT compounds, respectively. We must assume that the increase in the percolation threshold for m-NT maps of smaller aspect ratio r. Exhibitor conductivity in-HT and m-HT within the error of the same and are both types of NT t ~ 3.3 ± 0.1). The microstructure of the obtained concentration of nanotubes is not stable, and eventually the transition from primary branched aggregates of NT (L-units) to the C-units with a more compact structure (during heat incubation for 1 week). The main theoretical results of work are: to construct a molecular model of aggregation of carbon nanotubes in liquid crystal medium; obnaruzhenik theoretical correlation between the concentrations of nanotubes, their aspect ratio, the fractal dimension of aggregates produced and the volume particle aggregates of nanotubes in their dispersion in the nematic matrix; ther dispersions of multiwall carbon nanotubes in liquid crystal matrix based on the cyanobiphenyl obtained by differential scanning calorimetry; identification of patterns of changes calorimetric peaks nematic-isotropic transition in the aggregation of nanotubes in their dispersions in liquid crystal matrix, establishing the difference between the thermodynamic behavior of the nematic matrix in the free state and in the aggregates formed by the nanotubes, the experimental determination and theoretical interpretation of the dependence of the aggregation process from the aspect ratio of nanotubes. Developed and greatly improved methods of interference investigations of optical vortices, and other optical singularities that arise in the nonstationary optical field, which arises in the diffraction of the laser beam on the nanocomposites with the thermodynamic instability. Product Description popup.authors Васильєв Василь Ігоревич Поневчинський Владіслав Вікторович Соскін Марат Самуїлович popup.nrat_date 2020-04-02 Close