46 research outputs found
Influence of the Electrodeposition Conditions on the Energetics of Polypyrrole Thin Films
No full textThe influence of the solvent used for the electrodeposition and that of the dopant anion on the energetics of
electrochemically grown polypyrrole were studied by means of a non-destructive optical technique: Photocurrent
Spectroscopy. Polypyrrole films doped with the same anion and grown in different solvents, both aqueous and non-
aqueous, show the same HOMO-LUMO gap and the same Fermi level location in respect to HOMO. Polypyrrole films
doped with different anions in aqueous solutions, present different values of indirect band gap and flat band potential,
indicating that dopant anion influences both the defects band and the Fermi level locations
Comparative study of the various methods of preparation of silicate solution and its effect on the geopolymerization reaction
No full textAbstractThis paper is based on the characterization of synthesized geopolymer binders based on either powder or solution silicate, and the amount of water contained in synthesized binders is determined to evaluate their possibility to coat a brick. The structural evolution of the formed geopolymers was investigated using FTIR spectroscopy. The mechanical properties were evaluated using compression tests. The structural evolution ensured that the solutions prepared from silicate powder or liquid had different degrees of polymerization, which modified the polycondensation reaction of the mixture. Nevertheless, the use of aluminosilicate solutions based on powder or liquid display similar behavior in a polycondensation reaction. The obtained materials show good mechanical properties, and it is possible to deposit this binder on the brick depending on the water content
Third order NLO properties of modified azo-azulenes
No full textIn this work there are reported third order nonlinear optical properties of some new azo- functionalized azulene derivatives. They were studied using standard methods - degenerate four waves mixing and third harmonic generation and nonlinear optical absorption. The obtained results allow us to conclude that NLO properties of an azulene molecule can be significantly enhanced by substitution with an electron accepting an acetamidophenyl group
Les rotaxanes et caténanes : des nanomoteurs prometteurs pour applications ONL
No full textDate du colloque : 06/2008</p
Azo-azulene based compounds-nonlinear optical and photorefractive properties
No full textThis work reports on nonlinear optical properties of some azo-functionalized azulene derivatives. Linear and nonlinear optical absorption, second- and third harmonic generation were used as diagnostic tools. It was demonstrated that light induced a surface pattern on thin films containing the studied compounds. The results indicate an important role of thiazole substitution for enhancing NLO properties of the azulene derivatives
Thermal stability of blends containing azo-carbazole derivatives and epoxy resin, designed for nonlinear optical applications
No full textMany studies have been intended to synthesize new thermally stable organic materials and polymers for nonlinear optical applications. These materials are most often guest–host systems and present some inconveniences like solvents compatibility for both the matrix and the chromophore. In the present work, we propose to use an epoxy resin as matrix for chromophores. Three blends containing an epoxy resin and azo-carbazole derivatives (either physically dispersed or chemically bound) were studied. They were prepared in form of thin films. We report their nonlinear optical properties investigated by third harmonic generation (THG) by Maker fringes technique, as well as thermal stability of these characteristics. The results show different behaviour for dispersed chromophore in a matrix and covalently bounded chromophore
New class of highly conjugated nanomotors: catenanes and rotaxanes as potential candidates for nonlinear optical applications
No full textDate du colloque : 06/2008</p
Second and third order nonlinear optical properties of microrod ZnO films deposited on sapphire substrates by thermal oxidation of metallic zinc
No full text
