【作者】 朱玉萍；

【导师】 王西奎；

【作者基本信息】 济南大学 ， 应用化学， 2010， 硕士

【摘要】 本文利用超声化学法,以可溶性银盐为银源,在一定浓度的还原剂和稳定剂存在下,在水介质中制备出了盘状和棒状纳米银;而使用相同的银源、还原剂和稳定剂,在水/乙醇介质(1:1)中,则得到银微纳米管。通过扫描电子显微镜和透射电子显微镜观察其形貌及生长过程,并通过选区电子衍射、X-射线衍射、红外光谱及能谱对纳米银进行了表征。利用超声化学法制备盘状和棒状纳米银尚属首次,大尺寸银微米管的制备国内外未见报道。银纳米棒:将含有硝酸银(0.01 mol/L)、还原剂六次甲基四胺(HMTA 0.80 g/L)和稳定剂聚乙烯吡咯烷酮(PVP 0.40 g/L)的水溶液,在恒温条件下进行超声辐照,制备得到形貌均一的银纳米棒,平均长度6μm,直径50 nm。并利用透射电子显微镜(TEM)、扫描电子显微镜(SEM)和X射线衍射仪(XRD)对其进行表征。同时讨论了反应时间、稳定剂及反应温度等对纳米银形貌的影响。结果表明,银纳米棒的长度随着时间的延长而增加,随稳定剂浓度的增大而变短。论文通过红外分析提出了反应机理。银纳米盘:在上述反应体系中,保持硝酸银为浓度0.01 mol/L,增加稳定剂浓度(PVP 0.60 g/L),同时降低还原剂的含量(HMTA 0.20 g/L),30℃条件下,超声反应30 min,制备出直径200- 280 nm盘状纳米银。这是由于在低浓度还原剂条件下,银晶核受高浓度的稳定剂的抑制,生长缓慢,最终生长为表面光滑的盘状纳米银。随着稳定剂PVP浓度的增加,纳米盘直径规律性地变小,这可以作为控制银纳米盘直径大小的重要条件。论文还考察了还原剂和介质酸度对银纳米盘形貌的影响,并研究了盘状纳米银粒子的抗菌性能,结果表明此种盘状纳米银粒子具有良好的抗菌效果,其最小抑菌浓度为8μg /mL。银微纳米管:以硝酸银为银源、HMTA为还原剂、PVP为稳定剂,在水/乙醇介质(1:1)中,恒温30℃超声反应30 min,然后在4℃下陈化6天,得到银微米管。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X-射线衍射(XRD)对其进行表征,考察了陈化时间、稳定剂种类、还原剂浓度、介质pH值以及超声处理等因素对银微米管形貌的影响。结果表明,通过自组装过程形成的银微纳米管,其长度和形貌受还原剂浓度、稳定剂种类、体系pH值和陈化时间的影响,当用电磁搅拌代替超声后,银管形貌不均一。更多还原

【Abstract】 In this paper, silver nanorods and nanoplates have been synthesized by means of ultrasonic irradiation, with fusibility silver salt and a certain concentration of reducing agent and stabilizer in aqueous solution; And when we use the same silver source, reducing agent and stabilizer, but change the system to water / ethanol solution (1:1), a special morphology micro/nanotubes of silver was prepared. The process of growing can be monitored by transmission electron microscopy (TEM) and scanning electron microscope (SEM). The products were characterized by selected area electron diffraction (SAED), X-ray diffraction (XRD), IR spectrophotometer and energy dispersive spectra (EDS). This is the first time to synthesis silver nanorods and nanoplates using sonochemical method, and the preparation of large-size silver microtubes have not been reported whether at home or abroad.Silver nanorod: The reaction solution contains stabilizer PVP 0.40 g /L、reducing agent HMTA 0.80 g /L and silver source AgNO3 0.01 mol /L, under the conditions of constant temperature and ultrasonic irradiation, silver nanorods with uniform morphology was prepared, with average length of 6μm and diameter of 50 nm. We use transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray to characterize the morphology of silver nanorods. At the same time, the impact of the reaction time, stabilizer and reaction temperature on the silver nanorods morphology had been discussed. The experiment shows that the length of silver nanorods is increasing as the reaction time increased, and becoming shorter when the stabilizer concentration increased. The reaction mechanism is proposed by IR analysis.Silver nanoplates: In the above reaction system, we maintain the concentration of silver nitrate of 0.01 mol / L, reducing the concentration of reductant(HMTA 0.20 g/L), while increasing the concentration of stabilizer(PVP 0.60 g/L), then ultrasonic irradiation for 30 minutes at the temperature of 30℃, the silver nanoplates of 200- 280 nm in diameter were prepared. It shows that under the conditions of low concentration of reducing agent, the growth of silver nuclei was inhibited by high concentrations of stabilizing agent, and eventually grows into a plate with smooth surface. With the concentration of PVP stabilizer increasing, nanoplates regularly to become smaller in diameter, which can control the diameter and the size of silver nanoparticles; The paper also examines the effect of reducing agent and medium acidity on the morphology of silver nanoplates. In addition, silver nanoparticles have good antibacterial properties, the results showed that the minimum inhibitory of silver nanoparticles concentration is 8μg /mL.Silver micro/nano-tubes: In this study, we use silver nitrate as silver source, HMTA as the reducing agent, PVP as stabilizer to prepare silver colloid in the organic system of water/ethanol (1:1) under the conditions of constant temperature 30℃and ultrasonic irradiation for 30 min. After 6 days aging at 4℃, the silver microtubes were formed. The silver microtubes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). By changing the aging time, stabilizer type, concentration of reducing agent, medium pH and ultrasound treatment, we investigated the morphology differences of silver microtubes. The results showed that it is a self-assembly process to form silver micro/nano-tubes, its length and shape are affected by the reducing agent concentration, stabilizer type, pH value and aging time. When we use stirring instead of ultrasound, the morphology of the silver tubes were heterogeneity.更多还原