Planar and Three-Dimensional Printing of Conductive Inks

Printed electronics rely on low-cost, large-area fabrication routes to create flexible or multidimensional electronic, optoelectronic, and biomedical devices1-3. In this paper, we focus on one- (1D), two- (2D), and three-dimensional (3D) printing of conductive metallic inks in the form of flexible, stretchable, and spanning microelectrodes

Device fabrication: Three-dimensional printed electronics

Engineering and Applied Science

Wet-chemical synthesis of crystalline BaTiO3 from stable chelated titanium complex: Formation mechanism and dispersibility in organic solvents

Crystalline barium titanate nanoparticles were synthesized in solution at low temperature (70 degrees C) from acetylacetone chelated titanium complex and barium hydroxide. Very fine crystalline solids were characterized to cubic phase of BaTiO3 by X-ray diffraction studies of the air-dried samples. It was observed that the crystalline barium titanate was formed in solution at Ba/Ti molar ratio >= 2.5. The dependence of the reaction temperature and the Ba(OH)(2) concentration (in terms of Ba/Ti molar ratio) on formation of crystalline BaTiO3 in solution-phase was studied, and a plausible mechanism toward the formation of crystalline BaTiO3 was also proposed. Crystallite sizes of the BaTiO3 were found to be in the range 33-50 nm, while the average particle sizes, measured by dynamic light scattering method were in the range 70-100 nm. The crystalline BaTiO3 prepared from acetylacetone chelated titanium complex was highly dispersible in organic medium such as N-methyl-2-pyrillidone (NMP) and N,N-dimethyl formamide (DMF). (c) 2006 Elsevier Inc. All rights reservedclose1

Wet chemical synthesis of redispersible crystalline BaTiO3 in organic medium

Redispersible crystalline BaTiO3 nanoparticles were prepared by wet chemical method from alkoxide-hydroxide precursor in the presence of ethylene diamine. Crystal structure, crystallite size and morphology of BaTiO3 nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The crystallite sizes of the BaTiO3 nanoparticles were found to be in the range 24-43 nm, while the average particle sizes, measured by dynamic light scattering method and SEM were in the range 55-120 nm. The dispersibility of BaTiO3 nanoparticles in organic media was remarkably enhanced by preparing them under the presence of ethylene diamine. The dispersion stability of the nanoparticles was higher in the organic media such as methanol and N,N-dimethyl foramide with relatively high dielectric constants than organic media such as isopropyl alcohol, methyl isobutyl ketone and cyclohexanone with low dielectric constants. (C) 2007 Published by Elsevier B.Vclose

Effects of reactant concentration and OH- ions on the formation of nanocrystalline BaTiO3 in solution

Crystalline BaTiO3 nanoparticles were prepared in solution at low reaction temperature. The formation of crystalline BaTiO3 and its crystallite size was strongly dependent on the concentration of the OH- ion, total concentration of the reactants, reaction temperature and reaction time. The formation pathway and the variation of crystallite size were understood by several model experiments using NaOH as the additional source of OH- ions. At higher OH- concentrations, the crystallite size of BaTiO3 was found to be decreased with increasing OH- concentrations, while it was increased with increasing reactant concentrations. (C) 2006 F blished by Elsevier Ltdclose1

Sol-gel micro encapsulation of hydrophilic active compounds from the modified silicon alkoxides: The control of pore and particle size

The present paper has demonstrated one-pot preparation of the spherical silica microcapsules containing hydrophilic active compounds using a water-in-oil microemulsion process from the modified silicon alkoxides with 3-aminopropyl triethoxysilane (APTES) as a gelling agent. The H2O to-TEOS molar ratio in the preparation of the encapsulation precursors played an important role on controlling the morphology and pore size of the microcapsules. The spherical microcapsules were obtained in the range Of H2O/Si=1.5-1.7. Outside this range no spherical microcapsules was observed because the precursors were not miscible with hydrophilic active compounds below the range and gelled too fast above the range. The average particle sizes of the microcapsules were controllable in the range of sub-micrometers to several tens of micrometers by adjusting agitation speeds, and the properties of the precursors. The pore size of the microcapsules can be also tuned by changing the H2O-to-TEOS molar ratio in the preparation of the encapsulation precursors. (c) 2007 Elsevier B.V. All rights reservedclose1

Preparation of inorganic-organic hyhrid titania sol-gel nanocomposite films, and their dielectric properties

Hybrid titania materials were prepared by a process involving the phase separation of TiO2 by hydrolysis and polycondensation from hybrids between titanium tetraisopropoxide (TTIP) and 3-(methacryloyloxy)propyl trimethoxysilane (MPTS) with excess acidic water at an elevated temperature (80 degrees C). The formation of TiO2 nanoparticles within the hybrid materials was studied as a function of the ageing time as well as the Ti/Si molar ratio. The crystalline phases of the TiO2 nanoparticles formed in situ within the inorganic-organic hybrid matrix were characterized by X-ray diffraction and Fourier transform infrared studies. The microstructures and the morphologies of thick films of the hybrid materials were studied using scanning and transmission electron microscopy, which showed the existence of nanocrystalline TiO2 within the crack-free hybrid matrix. The dielectric constants of the composites were found to be in the range 5.0-7.1, depending on the measuring frequency and the composite composition. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheimclose

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Core/shell silica-based in-situ microencapsulation: A self-templating method

Core/shell SiO2 and (RSiO1.5)(1-x)-(SiO2)(x) (R = alkyl) microcapsules were synthesized via a single-step O/W emulsion system using a self-templating method; the facile synthetic process provides an in-situ encapsulation route for a wide range of lipophilic functional compoundsclose2

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