柠檬酸银纳米乳液的合成与表征

Synthesis and characterization of silver citrate nano-emulsion

为了制备纳米层级有机酸银乳液，并考察其在制备纳米导电银膜方面的应用，在聚乙烯吡咯烷酮（PVP）存在的条件下，于水中通过硝酸银与柠檬酸钠反应，合成了柠檬酸银纳米乳液。将柠檬酸银纳米乳液涂布在PET片基上，并用抗坏血酸（Vc）水溶液对其进行还原，制备了纳米导电银膜。通过红外光谱仪、热分析仪、X射线衍射仪、激光粒度仪、紫外．可见光分光光度计、扫描电镜（SEM）等，对柠檬酸银纳米乳液，以及导电银膜性能进行了测试和表征。发现PVP保护的柠檬酸银乳液，粒度分布均匀。SEM观察表明，柠檬酸银呈长径比为5：1的棒状生长，直径约为20nm。银膜的UV-Vis吸收峰位于430nm，表明其具有纳米结构，表面电阻为2.42kΩ/cm。

To prepare the nano-scale silver carboxylate emulsions and investigate their applications in the conductive nano-silver films, the silver citrate emulsion was synthesized through the reaction of silver nitrate with sodium citrate in the presence of polyvinylpyrrolidone （PVP） as a protected agent in water. The emulsion was coated onto the PET substrate to form a thin latex layer of silver citrate. Then, it was deoxidized by aqueous ascorbic acid（Vc）. Properties of the silver citrate emulsion and the silver thin film on the PET substrate were fully characterized by FTIR, Thermogravimetry, X-ray powder diffraction, Laser particle size analyzer, UV-visible absorption spectroscopy, Scanning electron microscopy and so on. It was found that the silver citrate particle which was protected by PVP has a nano-rod structure and homogeneous size distribution. The nano-rod was about 20nm in diameter and 100nm in length. For the UV-Vis spectrum of the thin film exhibited an absorption peak at 430nm, the silver thin film was considered a typical nano-scale sliver film. The surface resistance of the film reached to 2.42kΩ/cm indicated that the silver film were electrically conductive.