Metallic nanoparticles are often obtained by chemical decomposition or reactive techniques involving the extensive usage of harmful reducing or stabilizing agents. A facile green synthesis technique resulting in readily exploitable nanoparticle dispersion in ionic liquid without the use of any additional agents is reported here. 1-Propyl- 3- Methyl Imidazolium Iodide (PMIM(I)) is a non-volatile, thermally stable and non-toxic ionic liquid. This eco-friendly liquid is used as the substrate for thermal evaporation of gold to obtain stable gold nanoparticles. On being examined by Transmission Electron Microscopy the high monodispersity in their sizes was revealed. The byproduct free, ‘clean’ processing technique helps in obtaining un-contaminated particles. The thermal evaporation method used (for the generation of metallic vapor) plays a significant role in the difference in kinetics of the formation and growth of nanoparticles, unlike the widely reported sputtering technique for vapor generation. The formed particles are deposited only on the top surface of the liquid. Thus the nucleation and growth of the particles can be considered to have occurred by surface diffusion process only. A deeper investigation into the formation kinetics has the potential application for synthesizing other nanomaterials via this environmental friendly approach.

For a sol-gel process occurring in a water/oil (w/o) system, the self-assembly of silica nuclei can be controlled by close control of synthesis conditions. We have synthesized ellipsoidal or spherical silica particles by a template-free scheme that involves controlling surface tension on silica nuclei through via use of different volume ratios of a w/o micellar system.

Dry-coated nanosilver is a promising material for bio-applications. Its inert and non-porous nanothin SiO2 coating preserves the plasmonic properties of the nanosilver and cures its toxicity by (1) preventing direct cell to silver contact and (2) blocking the release of toxic silver ions. However, fully hermetic coatings have, to date, not been produced. During the coating process, a certain number of core particles are either coated only partially, or escape the coating process entirely. Here, a systematic parametric study was undertaken in order to optimize an aerosol reactor for the synthesis and dry-coating of nanosilver. The reactor was optimized with respect to coating injection height, jet number, mixing flow rate. By synthesizing xAg/SiO2 composite particles, small silver sizes (9-11 nm) with relatively high Ag ion release were obtained. This enabled the quantitative evaluation of the coatings by Ag ion release measurements.

In this work we study the effect of different reducing agent (chitosan, starch and sugars) on to synthesis of silver (AgNPs) and gold (AuNPs) nanoparticles by reduction of silver nitrate (AgNO3) and chloroauric acid (HAuCl4), respectively. The plasmon absorption peak between 419 - 434 nm, measured using a UV-Vis spectrophotometer indicates the existence of AgNPs, this reaction was favored by the increase of temperature with optimal results at 90°C. Synthesis of AuNPs was only obtained using chitosan as reducing agent, the use of solutions of starch and sugars allows the reduction of the gold salt present in the chloroauric acid, however the low pH of the solutions creates thermodynamic instabilities for the AuNP synthesis, due to low repulsive force for colloid stability.

An aqueous magnetic suspension was prepared by dispersing amphiphilic co-polymer (ACP) coated monodispersed magnetite nanoparticles (MNPs) synthesized through thermal decomposition of iron(III) acetylacetonate in a mixture of oleic acid and oleylamine. ACP composed of poly (maleic anhydride-alt-1-octadecene) and polyethylene glycol methyl ether was applied to disperse MNPs in water and buffer solution. The average diameter of MNPs increased from 6.6 to 12.5 nm with increasing reaction temperature from 200 to 250°C. Infrared spectra and elemental analysis revealed that the surface modified MNPs contain carboxyl groups originated from oleic acid and ACP. The conjugation of MNPs and bovine serum albumin (BSA) antibody was examined. As a result, the as-synthesized MNPs adsorbed BSA antibody effectively than the surface modified MNPs: the BSA antibody adsorption decreased with increasing cross-linker concentration.

In recent years, there has been significant effort in the synthesis of nanocrystalline spinel ferrites due to their unique properties. Among them, zinc ferrite has been widely investigated for countless applications. As traditional ferrite synthesis methods are energy- and time-intensive, there is need for a resource-effective process that can prepare ferrites quickly and efficiently without compromising material quality. We report on a novel microwave-assisted soft-chemical synthesis technique in the liquid medium for synthesis of ZnFe2O4 powder below 100 °C, within 5 min. The use of β-diketonate precursors, featuring direct metal-to-oxygen bonds in their molecular structure, not only reduces process temperature and duration sharply, but also leads to water-soluble and non-toxic by-products. As synthesized powder is annealed at 300 °C for 2 hrs in a conventional anneal (CA) schedule. An alternative procedure, a 2-min rapid anneal at 300 °C (RA) is shown to be sufficient to crystallize the ferrite particles, which show a saturation magnetization (MS) of 38 emu/g, compared with 39 emu/g for a 2-hr CA. This signifies that our process is efficient enough to reduce energy consumption by ∼85% just by altering the anneal scheme. Recognizing the criticality of anneal process to the energy budget, a more energy-efficient variation of the reaction process was developed, which obviates the need for post-synthesis annealing altogether. It is shown that the process also can be employed to deposit crystalline thin films of ferrites.

The objective of the present study is to obtain the electrolyte material YSZ at low cost via sol gel, through exploration of the index rate between the complexing agents and the metallic salts (HMTA / metallic salts) from 1 to 5, prepared by a polymeric way in a sol gel process. We show an easy method that could be used in the industrial scale in order to obtain solid electrolyte material for its application in SOFC to operate at temperatures in the range of 700 800°C. This study has as reference the papers from Lenormand and Rieu about their synthesis of zirconium substituted to 8% of yttrium (CYSZ= 0.2 mol*L-1 metallic salts concentration-). The presence of the phase in the materials has been confirmed by X-ray diffraction assisted by thermal analysis tests, for indexes from 2 to 5 at a temperature of 1000°C for 5 hours at a calcination rate (from amorphous dust obtained at 400°C) of 1000°C per hour. The grain size mean for crystalline powder has an average near 50 nm and standard deviation close to 9 nm, it was confirmed by scanning electron microscope (SEM).

Cellulose nanofibrils have been evaluated as reinforcement material in polymeric matrixes due to their potential to improve the mechanical, optical, and dielectric properties of these matrixes as well as its environmental positive footprint. This work describes how banana nanocellulose can be used to replace others not so friendly materials in many applications including, biomaterials, automotive industries and packaging by proved with their mechanical properties. The process used is very mild to the environment and consists of a high pressure fibrillation followed by a chemical purification which affects the fiber morphology. Many fibers characterization processes were used including microscopy techniques and X-ray diffraction to study the structure and properties of the prepared nanofibers and composites. Microscopy studies showed that the used individualization processes lead to a unique morphology of interconnected web-like structure of the fibers.

Fulfilling the need for reproducible Quantum Dots (QDs) with certain spectroscopic features, high stability and luminescence we have established synthetic routes for the production of CdSe core as well as CdSe/shell particles in a continuous flow (cf) system. Our method features the deviation between nucleation and growth in two different parts of the system to mimic the well-known and often-used hot injection method for the synthesis of nanoparticles in organic solvents.

Due to its excellent thermal shock resistance, mechanical and chemical stability at both room and elevated temperatures, silicon carbide (SiC) is an attractive material for environmental protection and energy production applications such as catalyst supports, molten metal filters and gas separation membranes. Precise pore size control and high porosity are the key deciding factors for such applications. In this study, we demonstrated the fabrication of bi-layered SiC membranes with a graded porosity, consisting of porous nano-SiC layer on the surface of a porous coarse-grained SiC support layer. Nano-SiC powders utilized for this study were synthesized using a novel process based on mechanical activation of silica fume and graphite mixtures, resulting in particle sizes as small as 30 nm. The effects of sintering temperature were investigated to control the pore size, particle size and overall density of the bi-layered membrane.

Graphite that had been ball-milled for 10 h in 3 bar hydrogen, was then mixed with lithium borohydride (2:1 molar ratio of graphite to LiBH4) and milled for a further 2 h. This resulted in a significantly enhanced the hydrogen desorption properties: compared with the pure hydrogenated milled graphite, added LiBH4 lowered the desorption temperature by 170°C, to 230°C, and increase the hydrogen desorption from 5.6 to 9.3 wt%, heating to 500°C. There was no detectable methane generation in the desorption gas.

Ceramics of alumina of high density and purity can have a broad application area due to the combination of the excellent properties such as resistance to corrosion, good biocompatibility, and high resistance to wear and moderate mechanical resistance. But its low fracture toughness limits its range of applications. One possibility of improvement in the properties of these materials might be in the use of nanometric inclusions of ZrO2 into the matrix of Al2O3. The aim of this paper was to obtain and characterize the nanocomposites of alumina containing 0, 5, 10, 15 and 30 vol% of nanometric zirconium, seeking improvements in the mechanical properties and its comparison with values found for the matrix without the inclusion. For that, nanometric particles of ZrO2 were added into the matrix of alumina in the different proportions, using mixture of suspensions. The samples of alumina and nanocomposites of alumina-zirconium were physically, microstructurally and mechanically characterized. The results obtained, showed the efficiency of the used process, obtaining a good dispersion of the particles of zirconium in the matrix of alumina. The adding of up to 15vol% nanometric zirconium in the matrix of alumina promoted an increase in the values of the mechanical properties when compared with alumina. For the nanocomposites containing 30vol%, a good dispersion of the zirconium inclusions did not happen, leading to inferior values in the measured properties.