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

明尼苏达大学双城分校和密歇根大学安娜堡分校之间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-中性原子和分子，带电自由基和离子以及电子的反应气体。化学反应性液体在整个社会中使用，从家庭清洁液到制药定制解决方案;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项挑战，特别是当活性物质的寿命较短时。大气压等离子体是产生化学反应性的理想介质;并且等离子体-液体相互作用利用在等离子体中产生化学反应性物质的能力以在液体中产生独特的化学反应性。 该项目还将开发和支持每年一次的为期一周的美国低温等离子体学校，旨在为来自全国各地的研究生提供沉浸在低温等离子体科学中的机会，并向其领域的领先研究人员学习。我们将研究单个水滴与受控扩散的冷大气压等离子体之间的相互作用，其目的是对反应进行量化等离子体产生的物种与液体。 当传输和反应高度耦合时，在气体等离子体和液体之间的边界附近发生的反应动力学，导致界面传输，变得越来越复杂。当传输包括短寿命的高反应性物质（如在等离子体和液相中）并且物质转移是传输受限的时，通常是这种情况。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降低到最低限度的机会。 明尼苏达大学的实验装置将独特地使等离子体与已知初始和最终组成的单个液滴的相互作用的研究成为可能，该液滴穿过具有良好特征的等离子体。密歇根大学的多相等离子体建模将全面解决这个复杂的系统。预期结果将特别阐明液滴充电、等离子体诱导液滴蒸发、短寿命物种的运输机制和对流运输效应。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值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.