Shrestha Lok Kumar, Shrestha Rekha Goswami, Vilanova Neus, Rodríguez-Abreu Carlos, Ariga Katsuhiko
J Nanosci Nanotechnol. 2014 Mar;14(3):2238-44. doi: 10.1166/jnn.2014.8548.
In this paper, we report the one-step synthesis of metallic silver nanoparticles (Ag NP) using nonionic surfactant reverse micelle as nanoreactors. Diglycerol monolaurate (C12G2) spontaneously self-assemble into spheroid reverse micelles having size 10-12 nm in cyclohexane under ambient conditions of temperature and pressure. The spheroid C12G2 reverse micelles swell with water. Swollen reverse micelles having size - 20 nm are formed upon incorporation of 1% water. We used C12G2 reverse micelles as nanoreactors for making ordered nanostructure of Ag-NP by replacing water with aqueous silver nitrate solution. The diglycerol moiety of the surfactant reduces silver ions into metallic silver and thereby stabilizes the generated Ag NP. We found that shape and size of the Ag NP is closely related to the structure of nanoreactor. Similar results have been observed in linear chain alkane n-octane. We found bigger Ag NP from the C12G2/octane reverse micelle system as the size of the micelle in this system is bigger than that of the C12G2/cyclohexane system. This simple approach based on in-situ reduction of metal ions (without the need of reducing agent) opens a new possibility for the development of controlled synthesis of nanostructured noble metallic nanoparticles.
在本文中，我们报道了使用非离子表面活性剂反胶束作为纳米反应器一步合成金属银纳米颗粒（Ag NP）的方法。在常压和常温条件下，二月桂酸二甘油酯（C12G2）在环己烷中自发自组装成尺寸为10 - 12 nm的球形反胶束。球形的C12G2反胶束会吸水膨胀。加入1%的水后会形成尺寸约为20 nm的膨胀反胶束。我们用C12G2反胶束作为纳米反应器，通过用硝酸银水溶液代替水来制备有序结构的Ag - NP。表面活性剂的二甘油部分将银离子还原为金属银，从而稳定生成的Ag NP颗粒。我们发现Ag NP的形状和尺寸与其纳米反应器的结构密切相关。在直链烷烃正辛烷中也观察到类似结果。我们发现，由于C12G2/正辛烷反胶束体系中的胶束尺寸比C12G2/环己烷体系中的大，所以从该体系中得到的Ag NP颗粒更大且尺寸更大。这种基于金属离子原位还原（无需还原剂）的简单方法为可控合成纳米结构贵金属纳米颗粒开辟了新的可能性。
