Collaborative Research: Understanding Plasma-Liquid Interactions Through Controlled Plasma-Microdroplet Experiments and Modeling

明尼苏达双城大学和密歇根大学安娜堡分校的这项合作研究项目将研究水滴与大气压等离子体的相互作用。大气压等离子体是一种由中性原子和分子、带电自由基和离子以及电子组成的反应气体。化学反应液体在整个社会中被广泛使用，从家庭清洁液到用于制药制造的定制解决方案；现在越来越多地用于生物医学应用。定制这些液体的反应性是一个挑战，特别是在活性物种寿命较短的情况下。大气压等离子体是产生化学反应的理想介质；而等离子体-液体相互作用利用在等离子体中产生化学反应物种的能力，在液体中产生独特的化学反应。该项目还将开发和支持每年一周的美国低温等离子体学院，旨在为全国各地的研究生提供沉浸在低温等离子体科学中并向该领域的领先研究人员学习的机会。在这个研究项目中，将研究单个水滴与受控扩散的冷大气压等离子体的相互作用，目的是量化等离子体产生的物种与液体的反应。当传输和反应性高度耦合时，发生在气体等离子体和液体之间边界附近的反应动力学变得越来越复杂，从而导致界面传输。通常情况下，传输包括短暂的高活性物种，如在等离子体和液体中，而物种传输是有限的。气溶胶和散布在气体等离子体中的小液滴的等离子体活化提供了将运输限制减少到最低限度的机会。明尼苏达大学的实验设备将独特地使研究等离子体与已知初始和最终组成的单个液滴通过特征良好的等离子体的相互作用成为可能。密歇根大学的多相等离子体建模将全面解决这一复杂系统。预期的结果将特别阐明液滴充电、等离子体诱导的液滴蒸发、短寿命物种的传输机制和对流传输效应。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This collaborative research project between University of Minnesota-Twin Cities and University of Michigan-Ann Arbor will study the interaction of a water droplet with an atmospheric pressure plasma - a reactive gas of neutral atoms and molecules, charged radicals and ions, and electrons. Chemically reactive liquids are used throughout society, from cleaning fluids in the home to customized solutions for pharmaceutical manufacturing; and now increasingly in biomedical applications. Customizing the reactivity of these liquids is a challenge, particularly when the active species have short lifetimes. Atmospheric pressure plasmas are an ideal medium to produce chemical reactivity; and plasma-liquid interactions leverage the ability to generate chemically reactive species in plasmas to produce unique chemical reactivity in the liquid. This project will also develop and support an annual one-week US Low Temperature Plasma School aimed to provide opportunities for graduate students from across the country to be immersed in low temperature plasma science and learn from leading researchers in their field.In this research project, the interaction of a single water droplet with a controlled diffuse cold atmospheric pressure plasma will be investigated with the goal of quantifying the reaction of plasma produced species with liquids. The reaction kinetics occurring near the boundary between the gas plasma and liquid, resulting in interfacial transport, becomes increasingly complex when transport and reactivity are highly coupled. This is often the case when transport includes short-lived highly reactive species as in both the plasma and liquid phases, and species transfer is transport limited. Plasma activation of aerosols and small liquid droplets interspersed in the gas plasma provides opportunities to reduce transport limits to a minimum. The experimental apparatus at University of Minnesota will uniquely enable the investigation of plasma interactions with a single droplet of known initial and final composition, passing through a well-characterized plasma. Multi-phase plasma modeling at University of Michigan will comprehensively address this complex system. The anticipated results will, in particular, elucidate droplet charging, plasma induced droplet evaporation, transport mechanisms of short-lived species and convective transport effects.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.