In Situ Detection of Chemical Compositions at Nanodroplet Surfaces and In-Nanodroplet Phases
In Situ Detection of Chemical Compositions at Nanodroplet Surfaces and In-Nanodroplet Phases
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DOI：
10.1021/acs.jpca.2c03346
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发表时间：
2022-06-16
影响因子：
2.9
通讯作者：
Rao, Yi
中科院分区：
文献类型：
--
作者：
Qian, Yuqin;Brown, Jesse B.;Rao, Yi
小体积纳米液滴在化学和生物学中发挥着越来越常见的作用。这种纳米液滴被认为在液滴与其周围介质之间的界面上具有独特的化学和物理性质，然而，它们没有得到充分的研究。在这项研究中，我们提出了一种新的振动和频率散射(VSFS)光谱技术，作为一种特定于界面的、高性能的方法，用于原位研究亚微米半径的纳米液滴以及通过同步超拉曼散射(HRS)光谱来研究液滴整体。我们使用实验室生成的来自乙醇水溶液的纳米液滴来演示这项技术将液滴表面发生的振动现象与潜在的体相分离的能力。此外，我们通过VSFS系统地研究了含有甲醇、乙醇、正丙醇和正丁醇的纳米液滴的界面光谱。此外，我们还展示了这种纳米液滴与其类似平面之间的界面差异。这项技术在标准条件下探测小颗粒密度的液滴表面的敏感性证实了VSFS是一种原位研究小纳米液滴的分析技术，提供了关于这些物种的突破性信息，具有越来越重要的意义。
Small-volume nanodroplets play an increasingly common role in chemistry and biology. Such nanodroplets are believed to have unique chemical and physical properties at the interface between a droplet and its surrounding medium, however, they are underexamined. In this study, we present the novel technique of vibrational sum frequency scattering (VSFS) spectroscopy as an interface-specific, high-performance method for the in situ investigation of nanodroplets with sub-micron radii; as well as the droplet bulk through simultaneous hyper-Raman scattering (HRS) spectroscopy. We use laboratory-generated nanodroplets from aqueous alcohol solutions to demonstrate this technique's ability to separate the vibrational phenomena which take place at droplet surfaces from the underlying bulk phase. In addition, we systemically examine interfacial spectra of nanodroplets containing methanol, ethanol, 1-propanol, and 1-butanol through VSFS. Furthermore, we demonstrate interfacial differences between such nanodroplets and their analogous planar surfaces. The sensitivity of this technique to probe droplet surfaces with few-particle density at standard conditions validates VSFS as an analytical technique for the in situ investigation of small nanodroplets, providing breakthrough information about these species of ever-increasing relevance.