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Báo cáo hóa học: " Synthesis and Characterization of Monodispersed Copper Colloids in Polar Solvents"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Synthesis and Characterization of Monodispersed Copper Colloids in Polar Solvents | Nanoscale Res Lett 2009 4 465-470 DOI 10.1007 S11671-009-9264-3 NANO EXPRESS Synthesis and Characterization of Monodispersed Copper Colloids in Polar Solvents Wei Yu Huaqing Xie Lifei Chen Yang Li Chen Zhang Received 5 November 2008 Accepted 27 January 2009 Published online 19 February 2009 to the authors 2009 Abstract A chemical reduction method for preparing monodispersed pure-phase copper colloids in water and ethylene glycol has been reported. Owing to the reduction property of ethylene glycol the reaction rate in ethylene glycol is higher than that in water. In addition the amount of reducing agent can be reduced largely. Ascorbic acid plays roles as reducing agent and antioxidant of colloidal copper due to its ability to scavenge free radicals and reactive oxygen molecules. Thermogravimetric results reveal that the as-prepared copper nanoparticles have good stability and they begin to be oxidized at above 210 C. Polyvinyl pyrrolidone works both as size controller and polymeric capping agents because it hinders the nuclei from aggregation through the polar groups which strongly absorb the copper particles on the surface with coordination bonds. Keywords Chemical synthesis Monodispersed Copper colloid Polyvinyl pyrrolidone Introduction In recent years there is an increasing interest in the research on metal colloids due to the multiple applications involving their physical and chemical properties 1-3 . For example the magnetic fluids made of Fe metal particles have higher magnetization in comparison with the fluids containing magnetic-iron oxide Fe3O4 or y-Fe2O3 4 . Co W. Yu H. Xie H L. Chen Y. Li C. Zhang School of Urban Development and Environmental Engineering Shanghai Second Polytechnic University Shanghai 201209 China e-mail hqxie@eed.sspu.cn nanoparticles in a colloidal solution can assemble into highly constrained linear chains along the direction of the magnetic field and the magnetic-field-induced chains become floppy after removal of the field folding