tailieunhanh - Báo cáo "Ảnh hưởng pH và khối lượng phân tử chitosan đến keo bạc nano chế tạo bằng phương pháp chiếu xạ "

Ảnh hưởng pH và khối lượng phân tử chitosan đến keo bạc nano chế tạo bằng phương pháp chiếu xạ | TẠP CHÍ KHOA HỌC VÀ CÔNG NGHỆ Tập 47 số 6 2009 Tr. 47-52 THE EFFECT OF pH AND MOLECULAR WEIGHT OF CHITOSAN ON SILVER NANOPARTICLES SYNTHESIZED BY y-IRRADIATION DANG VAN PHU BUI DUY DU NGUYEN NGOC DUY NGUYEN TUE ANH NGUYEN THI KIM LAN VO THI KIM LANG NGUYEN QUOC HIEN 1. INTRODUCTION During the last decades developments of surface microscopy materials science biochemistry physical chemistry and computational engineering have converged to provide remarkable capabilities for understanding fabricating and manipulating structures at the atomic level. The rapid evolution of this new science and the opportunities for application promise that nanotechnology will become one of the dominant technologies of the 21S1 century 1 . The study on synthesis of metal nanoparticles is of interest in both research and technology. Among metal nanoparticles silver nanoparticles Ag-NPs have attracted considerable interest because of their novel properties and their potential application 2 3 . Different methods have been used for the synthesis of Ag-NPs from Ag solution such as chemical 4 electrochemical 5 photochemical reduction 6 ultrasonic spray pyrolysis 7 gamma and electron beam irradiation 3 8 . . Method for preparing Ag-NPs by exposure to ionizing rays provides several advantages such as the manufacturing process carries out at room temperature the sizes and size distribution of the particles are easily control and purely colloidal Ag-NPs can be obtained. In addition mass production at reasonable cost is possible 2 3 9 . It is well known that Ag in solution could be reduced by y-rays to Ag atoms while they would agglomerate if there is no protective substance. Hence an effective stabilizer is the key factor to fabricate densely dispersed Ag-NPs by irradiation method 10 . Several polymers having functional groups such as -NHj -COOH and -OH with high affinity for Ag atoms 2 to stabilize Ag-NPs such as PVA 11 PVP 3 5 alginate 9 CM-Chitosan 12 chitosan and oligochitosan 10 13 14 and so .