反应体系粘度对多元醇法制备银纳米线的影响

Effect of Viscosity of the Reaction Solution on the Profiles of Silver Nanowires Prepared by Using the Polyol Reduction Method

在多元醇还原制备银纳米线(AgNW)的反应中,聚乙烯吡咯烷酮(PVP)稳定剂发挥着"软模板"的作用。通过加入不同相对分子量的PVP,研究其加入量对制备AgNW的影响。结果表明,PVP通过改变体系的粘度影响AgNW的直径、线长和产率。在一定粘度范围内(2.5~7.5 mPa·s),AgNW的直径基本稳定(约30 nm);线长大致随反应体系粘度增加呈现先增后减的趋势,最长平均线长在中间粘度(约3 mPa·s)获得,其中加入PVP K60时可在中间粘度获得最大平均线长(16 nm);粘度通过控制溶液中的传质作用影响副产物比例,当粘度很低(<2.5 mPa·s)或很高(>7.5 mPa·s)时,颗粒和短棒副产物比例大。

Polyvinylpyrrolidone （PVP） acts as a ＆quot;soft template＆quot; in the preparative reaction of silver nanowires （AgNW） using polyalcohol reduction. The effect of PVP on AgNW profiles was investigated by adding different relative molecular weights and different quantities of PVP The results show that PVP affects the diameter, length and yield of AgNW via changing the viscosity of the system. The diameter of AgNW is basically fixed （at about 30 nm） in a certain range of viscosity from 2.5 to 7.5 mPa·s）. AgNW tends to lengthen at first and then to shorten as the viscosity of the reaction system continues to rise. The maximum average length （16 nm） can be achieved at the moderate viscosity level（- 3 mPa·s） when PVP K60 is used. The viscosity controls the mass transfer in the solution, and further affects the byproduct ratio. The resulting nanwires will be accompanied by a high ratio of particle or short-rod byproducts when the concentration is below 2.5 mPa·s or above 7.5 mPa·s.