13 documents found, page 1 of 2
MATERIAIS VÍTREOS E LUZ: PARTE 1
Nalin,Marcelo; Ribeiro,Sidney J. L.; Manzani,Danilo; Gonçalves,Rogéria Rocha; Poirier,Gael; Cassanges,Fabia Castro; Matos,Christiano J. S. de2015 is the Year of Light, according to UNESCO. Chemistry has a close relationship with light and one of the materials that allows such synergy is glass. Depending on the chemical composition of the glass, it is possible to achieve technological applications for the whole range of wavelengths extending from the region of the microwave to gamma rays. This diversity of applications opens a large range of research...
MATERIAIS VÍTREOS E LUZ: PARTE 2
Nalin,Marcelo; Ribeiro,Sidney J. L.; Manzani,Danilo; Gonçalves,Rogéria Rocha; Poirier,Gael; Cassanges,Fabia Castro; Matos,Christiano J. S. deIn this second part it will be discussed some photonic applications of glassy and glass ceramic thin films which can be used as planar waveguides. Some photonic applications require certain specifications of glass, which can be quantified by studying the nonlinear optical properties of the materials. Therefore, a brief introduction of these phenomena is discussed, as well as the use of femtosecond lasers to man...
Bacterial Cellulose Membranes as a Potential Drug Delivery System for Photodyna...
Peres,Maristela F. S.; Nigoghossian,Karina; Primo,Fernando L.; Saska,Sybele; Capote,Ticiana S. O.; Caminaga,Raquel M. S.; Messaddeq,YounesThe development of drug delivery systems for photodynamic therapy (PDT) is increasingly demanded due to the hydrophobicity presented by most of photosensitizers molecules. Bacterial cellulose (BC), a highly pure cellulose produced by bacteria, possesses the essential features for applications in drug delivery systems, such as large surface area and excellent loading capacity. BC membranes prepared containing a ...
Luminescent Terbium Doped Aluminate Particles: Properties and Surface Modificat...
Caiut,José M. A.; Messaddeq,Younes; Dexpert,Hervé; Verelst,Marc; Ribeiro,Sidney J. L.; Dexpert-Ghys,JeannetteNew luminescent organic-inorganic hybrid particles based on Tb-doped aluminates and asparagine (Asn) surface modifiers were investigated. The Tb3+ doped inorganic core was obtained by spray pyrolysis, at 200 ºC γ-AlOOH (BOE:Tbx%) or at 700 ºC γ-Al2O3 (γTA:Tbx%). The reaction of Asn with boehmite in water disaggregated the sub-micronic boehmite particles to give stable dispersion of surface modified nanoparticle...
Biossíntese e recentes avanços na produção de celulose bacteriana
Donini,Ígor A. N.; Salvi,Denise T. B. De; Fukumoto,Fabiana K.; Lustri,Wilton R.; Barud,Hernane S.; Marchetto,Reinaldo; Messaddeq,YounesO presente trabalho discute os recentes avanços na biossíntese e na produção de celulose bacteriana (CB) pela gram-negativa, aeróbia e aceto-ácida Gluconacetobacter. xylinus. A CB se difere de seu par vegetal, principalmente devido ao seu caráter de fibras nanométricas, contra o caráter micrométrico da vegetal, são extruídas através da parede celular de G. xylinus, com isso sua estrutura macroscópica é mecanica...
Peak separation by derivative spectroscopy applied to ftir analysis of hydroliz...
Aragão,Bernardo J. G. de; Messaddeq,YounesReliable spectral analysis is only achieved if the spectrum is thoroughly investigated in regard to all hidden and overlapped peaks. This paper describes the steps undertaken to find and separate such peaks in the range of 3000 to 4000 cm-1 in the case of three different infrared absorption spectra of the glass surface of hydrolyzed silica optical fibers. Peak finding was done by the analysis of the second and ...
Structure and properties of Ti4+-ureasil organic-inorganic hybrids
Molina,Celso; Dahmouche,Karim; Hammer,Peter; Bermudez,Verónica de Zea; Carlos,Luís D.; Ferrari,Maurizio; Montagna,Maurizio; Gonçalves,Rogéria R.Hybrid planar waveguides were prepared from Ti4+-acetylacetone (acac)-Ureasil sols deposited on glass substrates. Structural features have been investigated by spectroscopic measurements (Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS) and Raman scattering) and Small Angle X-ray Scattering (SAXS). Addition of Ti4+-acac to the ureasil (Ti:Si molar ratio 1:1) leads to the fo...
Europium incorporated in silica matrix obtained by sol-gel: luminescent materials
Nassar,Eduardo José; Ciuffi,Katia Jorge; Ribeiro,Sidney José Lima; Messaddeq,YounesIn this work we report some aspects of the chemistry involved in the preparation of modified silicon oxide by the sol-gel process. Europium III compounds were used as luminescent probe. An organic-inorganic hybrid was obtained by hydrolysis of tetraethylorthosilicate (TEOS) and 3-aminopropyltriethoxysilane (APTS). The Eu III compounds were added in different ways. In the first, silica was prepared in the presen...
Filmes de titânio-silício preparados por "spin" e "dip-coating"
Nassar,Eduardo J.; Ciuffi,Katia J.; Gonçalves,Rogéria R.; Messaddeq,Younes; Ribeiro,Sidney J. L.The conditions for the preparation of luminescent materials, consisting of Eu3+ ions entrapped in a titanium matrix, in the forma of a thin film, using the sol-gel process, are described. The films were obtained from sols prepared with TEOS and TEOT, in the presence of acetylacetone as the hidrolysis-retarding agent, using the dip-coating and spin-coating techniques. The influence of these techniques on the fil...
Influência do pH na estabilidade dos coacervatos de prata como precursores vítreos
Montanari,Bianca; Vast,Pierre; Martines,Marco Antonio Utrera; Ribeiro,Sidney José Lima; Messaddeq,YounesNeste trabalho, usando o processo de coacervação, foi estudado o sistema NaPO3/AgNO3/H2O. Determinou-se o domínio de coacervação a partir de diferentes concentrações de NaPO3 e AgNO3 e a influência do pH na estabilização do coacervato foi determinada. Os coacervatos obtidos em pH ~ 5 apresentam maior região de estabilidade.