In Situ Probing of the Surface Properties of Droplets in the Air
In Situ Probing of the Surface Properties of Droplets in the Air
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DOI：
10.1021/acs.langmuir.3c00875
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发表时间：
2023-07-27
期刊：
影响因子：
3.9
通讯作者：
Rao，Yi
中科院分区：
文献类型：
--
作者：
Brown，Jesse B.;Qian，Yuqin;Rao，Yi
纳米液滴和微滴的表面特性与其在生物学、医学、生产、催化、环境和大气中的巨大应用密切相关。然而，许多用于分析液滴及其表面的方法是破坏性的、非界面特异性的、不在环境条件下进行、需要样品基底、原位进行或其组合。由于这些原因，需要一种在任何条件下进行表面选择性原位分析的技术。这篇专题文章介绍了用于空气中气溶胶液滴原位界面分析的二阶非线性光学散射技术的最新进展。首先，我们描述了此类液滴在各行业的广泛利用，以及它们独特的表面特性如何导致其普遍使用。然后，我们描述了液滴及其表面的基本特性，以及研究它们的常用方法。接下来，我们描述和频发生（SFG）光谱的基本原理、朗缪尔吸附模型，以及如何将它们一起用于描述平面液体和液滴表面的吸附过程。我们还讨论了悬浮在色散介质中的液滴的二阶散射的发展历史，并介绍了二次谐波散射（SHS）和和频散射（SFS）光谱。然后，我们继续概述空气中液滴的 SHS、电子和频散射 (ESFS) 和振动和频散射 (VSFS) 的发展，并讨论这些技术提供的有关液滴表面的基本见解。最后，我们描述了一些需要改进的空气液滴非线性散射领域，以及 SHS、ESFS 和 VSFS 在整个环境系统、界面化学和基础物理中的未来潜在方向和应用。这篇专题文章的目的是传播有关液滴及其独特表面特性的知识，并向可能不了解其适用性的最新进展和进步的广大受众介绍二阶非线性散射。
Surface properties of nanodroplets and microdroplets are intertwined with their immense applicability in biology, medicine, production, catalysis, the environment, and the atmosphere. However, many means for analyzing droplets and their surfaces are destructive, non-interface-specific, not conducted under ambient conditions, require sample substrates, conductedex situ, or a combination thereof. For these reasons, a technique for surface-selectivein situanalyses under any condition is necessary. This feature article presents recent developments in second-order nonlinear optical scattering techniques for thein situinterfacial analysis of aerosol droplets in the air. First, we describe the abundant utilization of such droplets across industries and how their unique surface properties lead to their ubiquitous usage. Then, we describe the fundamental properties of droplets and their surfaces followed by common methods for their study. We next describe the fundamental principles of sum-frequency generation (SFG) spectroscopy, the Langmuir adsorption model, and how they are used together to describe adsorption processes at planar liquid and droplet surfaces. We also discuss the history of developments of second-order scattering from droplets suspended in dispersive media and introduce second-harmonic scattering (SHS) and sum-frequency scattering (SFS) spectroscopies. We then go on to outline the developments of SHS, electronic sum-frequency scattering (ESFS), and vibrational sum-frequency scattering (VSFS) from droplets in the air and discuss the fundamental insights about droplet surfaces that the techniques have provided. Finally, we describe some of the areas of nonlinear scattering from airborne droplets which need improvement as well as potential future directions and utilizations of SHS, ESFS, and VSFS throughout environmental systems, interfacial chemistry, and fundamental physics. The goal of this feature article is to spread knowledge about droplets and their unique surface properties as well as introduce second-order nonlinear scattering to a broad audience who may be unaware of recent progress and advancements in their applicability.