Surface Characteristics that Drive Heterogeneous Ice Nucleation

驱动异质冰核的表面特性

• 批准号: 2304879
• 负责人: Miriam Freedman
• 金额: $ 64.76万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2304879&HistoricalAwards=false
• 关键词: Surface; Characteristics; Drive; Heterogeneous; Ice

With support from the Environmental Chemical Sciences Program in the Division of Chemistry, Professor Miriam Freedman and her graduate and undergraduate students at Pennsylvania State University will study the freezing behavior of atmospheric particles, or aerosols. Aerosols catalyze the formation of clouds in the atmosphere, which can be composed of liquid water, ice, or a mixture of these phases. Ice particles in clouds can form by the freezing of aqueous droplets below -38 degrees C, or ice can form on the surface of an ice-nucleating particle (INP) at warmer temperatures. How particles nucleate ice on a molecular level is not well understood. To investigate the surface features that promote the ice nucleation process, the approach used in this project is to work with materials in which the surface can be infinitely tuned and probed. The goal of this project is to provide a framework for understanding which surface features are important for ice nucleation and the relative importance of these different features. This project is important for atmospheric scientists developing models of cloud formation. In addition, this project is of interest to the physical chemistry community because it deals with phase transitions, catalysis, and surfaces. Ice nucleation experiments are ideal for the inclusion of undergraduate researchers, often leading to publications with undergraduate coauthors. Results from these studies will be incorporated into undergraduate course lectures. Students performing this work will also be engaged in public outreach to families as well as continuing education for members of the wider community.This project characterizes the ice nucleation behavior of inorganic systems as well as organic and biological systems. Similarities are hypothesized between mineral, organic, and biological ice nucleating particles (INPs) in terms of how structure determines the ice nucleation behavior. For inorganic systems, the role of functional groups and surface composition will be characterized using functionalized gold nanoparticles, porous metalosilicates, and spinels. In terms of organic and biological systems, this project aims to characterize the role of hydrogen bonding on ice nucleation through studies of virgin and aged microplastics, ice-nucleating bacteria and their isolated proteins, and poly(vinyl alcohol)/poly(vinyl acetate) with different degrees of hydrolysis. Experiments will be performed primarily using immersion freezing, which is a dominant pathway for ice nucleation in the atmosphere.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.

在化学系环境化学科学项目的支持下，宾夕法尼亚州立大学的Miriam Freedman教授和她的研究生和本科生将研究大气颗粒物或气溶胶的冷冻行为。气溶胶催化大气中云的形成，云可以由液态水，冰或这些相的混合物组成。 云中的冰粒可以通过在-38摄氏度以下的水滴冻结而形成，或者冰可以在更温暖的温度下在冰核粒子（INP）的表面上形成。 粒子如何在分子水平上使冰成核还没有很好的理解。为了研究促进冰成核过程的表面特征，该项目中使用的方法是使用表面可以无限调节和探测的材料。 这个项目的目标是提供一个框架，了解哪些表面特征是重要的冰成核和这些不同的功能的相对重要性。 这个项目对大气科学家开发云形成模型很重要。此外，这个项目是感兴趣的物理化学社区，因为它涉及相变，催化和表面。 冰成核实验是理想的纳入本科研究人员，往往导致与本科合著者的出版物。 这些研究的结果将纳入本科课程的讲座。 从事这项工作的学生还将参与家庭的公共宣传以及更广泛社区成员的继续教育。该项目描述了无机系统以及有机和生物系统的冰成核行为。 矿物，有机，和生物冰成核颗粒（INPs）之间的相似性假设在结构如何决定冰成核行为。对于无机系统，功能基团和表面组成的作用将使用功能化的金纳米粒子，多孔金属硅酸盐，和尖晶石的特点。 在有机和生物系统方面，该项目旨在通过研究原始和老化的微塑料、冰核细菌及其分离的蛋白质以及具有不同水解度的聚（乙烯醇）/聚（乙酸乙烯酯）来表征氢键对冰核的作用。实验将主要使用浸没式冷冻进行，这是大气中冰成核的主要途径。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。