VOL. 9, NO. 4, APRIL 2014 ISSN 1819-6608 ARPN Journal of Engineering and Applied Sciences © 2006-2014 Asian Research Publishing Network (ARPN). All rights reserved. www.arpnjournals.com 586 SYNTHESIS OF SILVER NANOPARTICLES Raid Salih Jawaad, Khalid F. Sultan and Ali H. Al- Hamadani University of Technology, Baghdad, Iraq E-Mail: dr99990@yahoo.in ABSTRACT Widely Silver nanoparticles have been investigated because they exhibit unusual optical, electronic, and chemical properties, depending on their size and shape, thus opening many possibilities with respect to technological applications. The silver nanoparticle is one of the inorganic nano materials which is a good antimicrobial agents. The researcher found that the bactericidal nano materials have opened a new epoch in pharmaceutical industries. Silver nanoparticles are the metal of choice as they hold the promise to kill microbe’s effectively and effect on both extracellularly as well intracellularly, the researchers by using different methods, manufactured silver nanoparticles with spherical, octahedral, tetrahedral, hexagonal, cubic, wire, coaxial cable, triangular prism, disc, triangular mark, belt, and shell shapes. Keywords: silver nanoparticles, surface plasmon, chemicals reduction. 1. INTRODUCTION There are different methods to synthesize silver nanoparticles, such as conventional temperature assisted process, controlled reaction at elevated temperatures, and microwave assisted process K. J. Sreeram et al., [1] Chemical, physical synthesis methods and Bioinspired synthesis. Chemical and physical methods lead to the presence of some toxic chemical species adsorbed on the surface that may have adverse effects in medical applications. Bioinspired synthesis of nanoparticles provides advancement over chemical and physical methods. Microbes generally have a harder time developing resistance to silver than they do to antibiotics.v.Parashar et al., [2] metallic nanoparticles shows unique properties such as excellent conductivity, chemical stability, and catalytic activity, etc. which are dependent on the particle size, size distribution and shape. Among all metals, silver has the highest electrical and thermal conductivity S. L-C Hsu, and R-T Wu [3]. The intrinsic properties of metal nanoparticles are mainly determined by their size, shape, composition, crystallinity, and structure. In principle, any one of these parameters could be controlled to fine-tune the properties of metal nanoparticles. D. Kim et al., [4]. Green synthesis of silver NPs using , Parthenium leaf Vyom Parashar et al., [2], citrus limon, latex of Jatropha curcas, starch, banana peel extract, leaf extract of Rosa rugosa, seed extract of Jatropha curcas, sucrose and maltose, Hibiscus rosa sinensis, cochlospermum gossypium honey and D. carotas, have been reported M. Umadevi [5]. 2. METHODS FOR PRODUCE NANO SILVER V. Parashar. et al., [2] used fresh leaves of Parthenium hysterophorus L. weighing 25 g were thoroughly washed thrice in distilled water for 15 min, dried, cut into fine pieces and were boiled in a 500 ml Erlenmeyer flask with 100 ml of sterile distilled water up to 5 min and were filtered, Silver nitrate (AgNO 3 ) 50 ml of fresh leaf extract was added into the aqueous solution of 1 mM Silver nitrate. Average size of the particles synthesized was 50 nm with size range 30 to 80 nm with irregular shape. Due to our interest to get much smaller particles, above solution was centrifuged at a rate of 1200 rpm up to 15 minutes and investigated that particles present in the supernatant were nearly homogenous with average size of 7 nm silver ion complex (1mM) and leaf extract it was observed that precursors in the ratio of 1:1 gave best results. S. L-C Hsu, and R - T Wu [3], dissolved AgNO 3 in de - ionized water in a beaker to this solution, a protecting agent [poly (N - vinyl - 2 - pyrrolidone or thiosalicylic acid or triethylamine] was added. After being stirred, HCHO solution was then added to the solution. Subsequently, a promoter (triethylamine or pyridine) was added drop wise. The color of the solution turned from clear to black. After being stirred for 200 min at room temperature, the precipitates were washed several times with ethanol, followed by centrifugation (6000 rpm, 10 min), to remove unbounded TEA. The particles were then dried at room temperature under vacuum for 24 h. The silver nanoparticles suspensions were prepared from the dried silver nanoparticles by re-dispersing them into alphaterpineol to prepare the nanoparticles in order to reduce the sintering temperature. As shown in Figure-2(a), when we used triethylamine as the reaction promoter and TSA as the protecting agent, the silver nanoparticles were successfully reduced from the AgNO 3 precursor. During the preparation of Ag nanoparticle suspensions, the individual particles had a tendency to form large agglomerates through the van der Waals force or Coulomb’s force. In order to prevent the agglomeration of small particles, we added TEA to the suspensions as the stabilizer. For TEA - protected silver nanoparticles, the agglomeration of small particles increased with the increasing TEA concentrations. Because the reduction reaction of AgNO 3 by formaldehyde is slow without the addition of basic catalysts. A higher pH is favored for higher reducing power. In order to avoid the use of inorganic bases as the reaction promoter, which usually contains other unwanted metal ions, we chose organic bases, triethylamine or pyridine as the reaction promoter. These bases are easy to be washed out after reaction and will not contaminate the resulting silver nanoparticles.