A review on the application of inorganic nano-structured materials in the modification of textiles: focus on anti-microbial properties

Silver nanoparticles are considered to apply a silver paste for electrode because of their high conductivity. However, the dispersion of silver nanoparticles in electronically conductive adhesives (ECAs) restricts them used as conductive fillers. A simple method had enabled the synthesis of silver nanoparticles by reducing silver nitrate with ethanol in the presence of poly(N-vinylpyrrolidone) (PVP). Reaction conditions, such as silver nitrate concentration, PVP concentration, reaction time, and reaction temperature, had been studied. Fine dispersion and narrow size distribution of silver nanoparticles were obtained. They were added to ECAs by re-dispersing them in ethanol while it was used as the diluent to adjust the volatility of ECAs, preventing them from the aggregation and increasing the chance to fill the gaps between silver flakes. This proposed process offers the possibility to effectively use these synthesized silver nanoparticles for improving the conductivity of ECAs.

Synthesis and electrical properties of uniform silver nanoparticles for electronic applications

Silver nanowires have attracted a lot of attention in both academia and industry because of their potential applications in many electronic devices In the past decade, there have been many research articles relating to silver nanowires, but there have been relatively few review articles focusing on these unique nanomaterials In this review, the definition and the characterization of silver nanowires will be introduced The synthetic methods employed to prepare silver nanowires and the factors that influence their final morphology will also be discussed in detail Examples of typical synthetic technologies and the representative studies will also be summarized and discussed In addition, the applications of silver nanowires as conductive materials and components of electronic devices will be reviewed Lastly, the challenges that remain with silver nanowires will be proposed Download : Download high-res image (92KB) Download : Download full-size image

Silver nanowires: Synthesis technologies, growth mechanism and multifunctional applications

There is an increasing interest in developing a low temperature interconnection process using nanoparticles. Some studies focus on bonding using Ag nanoparticles (Ag NPs). However, few studies investigate a bonding process using Cu nanoparticles (Cu NPs) due to the easy oxidation in air. Here we achieve a robust bonding of Cu wires to Cu pads with polyvinylpyrrolidone (PVP) coated Cu NPs at a low temperature of 170 °C. The PVP coating can effectively prevent the oxidation of Cu NPs when heated in air. The bonding is formed through the sintering of Cu NPs and direct metallic bonding between the sintered Cu particles and Cu pads. Electrical measurements of the Cu NPs demonstrate that Cu NPs have a low resistivity of 8.6 × 10−5 Ω cm after being sintered under pressure. This method has the potential to be used in the electrical packaging industry due to its economic cost, easy operation, and high conductivity.

Preparation of PVP coated Cu NPs and the application for low-temperature bonding

Highly conductive polymer nanocomposites with very low resistivity (4.8 × 10−5 Ω cm) were prepared by thermal sintering of silver nanoparticles with silver flakes dispersed in a polymer matrix at 180 °C. By comparative studies of thermal behavior of Ag nanoparticles, the critical processing temperature required to obtain very low resistivity of polymer nanocomposites has been identified for Ag nanoparticles with different surface properties. The results indicate that the decomposition temperature of surface residues on Ag nanoparticles plays a key role in the sintering of Ag nanoparticles and thus the electrical resistivity of the polymer nanocomposites. Electrical measurements of the polymer nanocomposites showed that morphological changes induced by sintering of Ag nanoparticle with Ag flakes considerably contribute to the reduction of the contact resistance between conductive fillers, increasing the nanocomposite conductivity.

Preparation of highly conductive polymer nanocomposites by low temperature sintering of silver nanoparticles

Effect of nano-sized silver particles on the resistivity of polymeric conductive adhesives

A method of fabricating barium titanate powders uses titanium tetrachloride and barrium hydroxide as reactants in a reaction solution. The pH value of the reaction solution is adjusted to strongly alkaline range by adding potassium hydroxide. Nitrogen is charged into a reaction tank at normal pressure, and the reaction solution is heated at 80-102° C. The solution is intensively stirred at constant temperature, and then subjected to a hydro-thermal reflux. Then, the solution is treated through an ion exchange resin and dried to obtain a cubic BaTiO 3 powders.

Methods of fabricating barium titanate powders

A method for preparing shape-changed nanosize colloidal silica comprising the following steps: a). providing a nanosize spherical colloidal silica solution having an average diameter no more than 100 nm; b). adding a coagulant having a concentration no more than 5 wt % and an active silicic acid to the colloidal silica solution, and raising the reaction temperature; and c). keeping addition of said active silicic acid to said solution obtained from step b) continuously until the concentration of SiO2 reaches 6 to 50% by weight.

Method for preparing shape-changed nanosize colloidal silica

A process for preparing lithium cobalite powders uses an oxalate gel method in which lithium nitrate and cobalt nitrate are used as starting reactants, oxalic acid as a chelating agent and water as a solvent. Oxalate sol is formed by the chelating reaction. After poly-condensation is conducted by heating, oxalate gel is formed. Continue heating to remove the solvent and water generated by the reaction to obtain dried gel powders. The dried gel powders are then thermally decomposed and sintered to form lithium cobalite powders LiCoO2 of a halite-type layered structure.

Process of preparing lithium cobalite powders

A chemical mechanical polishing slurry is provided for the copper layer on a wafer. The slurry contains colloidal silica and a chemical etching agent composed of hydrogen peroxide, acetic acid, and phthalic acid. The hydrogen peroxide oxides the surface of the copper layer. The acetic acid then reacts with the copper oxide to form copper acetate. This selective and functional chemical reaction mechanism can speed up the polishing removal rate and reduce scratches. The phthalic acid functions as both a pH buffering agent and a complexing agent to make the reaction concentration at each point of the wafer surface more homogeneous. Therefore, the copper layer during the chemical mechanical polishing process has a high removal rate and uniformity.

Zong-Whie Shih

Papers

Effect of nano-sized silver particles on the resistivity of polymeric conductive adhesives

Methods of fabricating barium titanate powders

Method for preparing shape-changed nanosize colloidal silica

Process of preparing lithium cobalite powders

Chemical mechanical polishing slurry for polishing copper layer on a wafer