Colloidal Dispersions
Mostrando 1-12 de 25 artigos, teses e dissertações.
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1. Aqueous Nanofluids Based on Copper MPA: Synthesis and Characterization
The application and use of efficient cooling fluids have become increasingly important due to the increasing industrial and energy demand associated with the miniaturization of various electronic devices. The search for high-efficiency heat exchanger fluids in the early 1990s led to the development of a new class of refrigerants called nanofluids. The use of
Mat. Res.. Publicado em: 11/01/2018
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2. Binary Micellar Solutions of Poly(Ethylene Oxide)-Poly(Styrene Oxide) Copolymers with Pluronic® P123: Drug Solubilisation and Cytotoxicity Studies
The non-commercial copolymers E45S8, E45S17 and their mixtures with Pluronic® P123 (E21P67E21) were studied as carriers of the model drug griseofulvin. Critical micelle concentration (cmc) (dye solubilisation method), drug solubilisation capacity (Scp and Sh) determined by ultraviolet-visible (UV-Vis) spectroscopy and 1H nuclear magnetic resonance (1H NMR)
J. Braz. Chem. Soc.. Publicado em: 2015-11
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3. Colloidal Dispersion Stability: Kinetic Modeling of Agglomeration and Aggregation
In this work we present a simple model for the kinetics of agglomeration and aggregation of colloidal particles. We consider that particles agglomerate rapidly and endothermically forming oligomers. These oligomers can, in turn, aggregate irreversibly, in a process that leads to the destabilization of the colloidal system. As these two processes have very di
J. Braz. Chem. Soc.. Publicado em: 2015-02
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4. EFEITO DA ESTRUTURA MOLECULAR DE LIGANTES DE SUPERFÍCIE EM PONTOS QUÂNTICOS DE CdTe DISPERSOS EM ÁGUA
Water-soluble CdTe quantum dots are synthesized to investigate how short-chain surface ligands bearing -SH, -COOH, and -NH2 groups interact with CdTe during nucleation/growth processes. Their optical properties and colloidal stability after the ligand exchange are also investigated. We then characterize the resulting CdTe by fluorescence, UV–Vis absorption
Quím. Nova. Publicado em: 2015-01
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5. Preparação e caracterização de suspensões coloidais de nanocarreadores lipídicos contendo resveratrol destinados à administração cutânea
Solid lipid nanoparticles (SLN), nanoemulsions (NE), and microemulsions (ME) were prepared by the hot solvent diffusion method, using tristearin or castor oil as oily phase, and soy lecithin and Solutol HS 15 as surfactants. Mean particle sizes ranged from 20 to 215 nm and negative zeta potentials were obtained for all nanocarriers. A HPLC method used to det
Química Nova. Publicado em: 2011
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6. Estudo das características morfológicas texturais e estruturais dos catalisadores automotivos, síntese e caracterização de filmes alternativos
The structural, morphological and textural changes of new and used automotive catalysts heated at temperatures between 500 and 1000°C were investigated. The catalysts were thermally characterized on simultaneous thermogravimetric and differential thermal analysis (TG-DTA) equipment performed in air and N2. Morphological changes were observed by scanning ele
Publicado em: 2010
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7. Estudo de materiais, estruturas de dispositivos e fenômenos de transporte em sistemas fotovoltaicos híbridos orgânico-inorgânico / Study of materials, device structures and transport phenomena in hybrid photovoltaic systems
Recently a fast development in organic and hybrid photovoltaic field has been observed. Such devices are fabricated by organic semiconductors within components of a heterojunction, in which bulk heterojunctions obtained via interpenetrating networks at the sub-20-nm length scale. It permits the effective collection of photogenerated charge carriers even with
Publicado em: 2010
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8. Repulsive and attractive ferroglasses: a SAXS and XPCS study
A dynamical freezing, which is the analogous of a glass transition, is observed at large concentrations in aqueous dispersions of maghemite nanoparticles. We study experimentally the structure and the dynamical properties of two dense ferroglass-formers in two very distinct states of interparticle interaction, either strongly repulsive or attractive. The sta
Brazilian Journal of Physics. Publicado em: 2009-04
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9. Gravitational and magnetic separation in self-assembled clay-ferrofluid nanocomposites
We report on experimental observations of self-assemblies in colloidal dispersions of clay nanoplatelets and magnetic nanoparticles. Visual observations have been combined with small angle X-ray scattering (SAXS) in the study of several composites at a fixed clay concentration in the dilute regime, and varying ferrofluid concentrations. Our visual observatio
Brazilian Journal of Physics. Publicado em: 2009-04
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10. Investigação da ordem local de nanocolóides magnéticos por espalhamento em baixo ângulo
In this work, we investigate using small angle scattering measurements the colloidal stability and the local order (typically between 10 nm and 100 nm) of magnetic nanocoloides, made of solution of magnetic ferrite nanospheres and mixed systems of magnetic nanospheres and laponite nanoplatelets. The balance of interparticles interactions has been quantitativ
Publicado em: 2009
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11. Preparação de emulsões complexas a partir de dispositivos de microfluídica / Production of complex emulsions using microfluidics devices
Emulsões são sistemas coloidais onde um líquido é disperso em outro líquido imiscível. O controle dessa dispersão pode trazer importantes contribuições para a ciência e para a sociedade, já que este tipo de sistema coloidal apresenta variadas e importantes aplicações nas áreas alimentícia, farmacêutica e de materiais. Este trabalho tem como o
Publicado em: 2009
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12. Caracterização eletroquímica de colóides magnéticos visando a aplicações nanotecnológicas nanobiotecnológicas
Electric Double Layered Magnetic Fluids (EDL-MF) are stable colloidal dispersions of spinel ferrite type nanoparticles in water medium. The thermodynamic stability is achieved by balancing the van der Waals and magnetic dipolar attractions with the introduction of repulsive electrostatic interactions between particles in order to avoid the agglomeration phen
Publicado em: 2008