Department of Applied Chemistry, School of Natural Science, Anhui Agricultural University, Hefei, Anhui 230036, P. R. China.
Langmuir. 2020 Sep 22;36(37):11110-11116. doi: 10.1021/acs.langmuir.0c02128. Epub 2020 Sep 13.
Dielectric spectroscopy was employed, for the first time, to monitor the formation process of silica nanoparticles in a nonionic surfactant-based microemulsion and in real time. Two dominant relaxations were observed in the frequency range of 1 MHz-3 GHz during this process. The relaxation at the lower frequency range was confirmed to be mainly ascribed to interfacial polarization, whose relaxation parameters, together with the electrical property of the synthesis system, were used to characterize the evolution of this dynamic formation process. Four evolution stages are distinctively revealed, including an induction stage, a nucleation dominant stage, an early particle growth stage, and a late growth stage. The dynamic features at each evolution stages were discussed in terms of the dielectric characteristics of the system. It is strongly suggested that dielectric spectroscopy is an effective tool for the mechanistic study of nanoparticle formation in microemulsion.
介电谱首次被用于实时监测非离子表面活性剂基微乳液中二氧化硅纳米颗粒的形成过程。在这个过程中，在 1 MHz-3 GHz 的频率范围内观察到两个主要的弛豫。低频范围内的弛豫被证实主要归因于界面极化，其弛豫参数与合成系统的电学性质一起用于表征这个动态形成过程的演化。四个明显的演化阶段被揭示出来，包括诱导阶段、成核主导阶段、早期颗粒生长阶段和晚期生长阶段。根据系统的介电特性，讨论了每个演化阶段的动态特征。强烈建议介电谱是研究微乳液中纳米颗粒形成的机制的有效工具。
