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دانلود رایکان مقاله انگلیسی ISI با موضوع ترکیب نانو ذرات طلا و نقره تثبیت شده – پلی ساکاریدی

عنوان فارسی مقاله:

ترکیب نانو ذرات طلا و نقره تثبیت شده – پلی ساکاریدی: یک روش سبز

عنوان انگلیسی مقاله:

Synthesis of polysaccharide-stabilized gold and silver nanoparticles: a green method

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بخشی از مقاله انگلیسی :

2. Results and discussion

Chitosan, the structure of which is shown in Figure 1a, is a polysaccharide obtained by partial deacetylation of chitin. Recently, chitosan has been used as a protecting polymer for the preparation of gold nanoparticles,20 but no reports have appeared describing the use of this polymer as a reducing agent in synthesis of metal nanoparticles. The method for the preparation of gold nanoparticles using chitosan as both a reducing agent and a protecting agent is quite simple. In a typical preparation, 100lL of a 20mM aqueous solution of HAuCl4 was mixed with 3mL of an aqueous solution of chitosan (2.0mg/mL, 100% deacetylated, Fluka). The mixture was heated to 55C and kept at this temperature while stirring in a water bath. After approximately 2 h, a red solution was obtained, indicating the formation of gold nanoparticles. The heat source was then removed and the solution was allowed to cool to room temperature while stirring. The gold nanoparticles prepared using chitosan as a protecting agent were of high monodispersity, and are comparable to citrate-stabilized gold nanoparticles with regard to shape and stability.21 A plasmon absorption band, characteristic of gold nanoparticles, was observed at 522 nm, as shown in Figure 2 (solid line).