The Role of Interstitial Air Layer in Drop Impact on Liquid-infused Surfaces

间隙空气层在液体注入表面的液滴冲击中的作用

• 批准号: 1705745
• 负责人: Ying Sun
• 金额: $ 31.9万
• 依托单位: Drexel University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2022-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1705745&HistoricalAwards=false
• 关键词: Role; Interstitial; Air; Layer; Drop

Liquid-infused surfaces have attracted great interest in recent years due to their super slippery properties upon drop impact and potential benefits in self-cleaning and anti-fouling applications without much understanding of the underlying physics. The proposed project seeks to address this issue by examining the drop impact dynamics on lubricated and liquid-infused surfaces, with a focus on probing the role of the entrained air layer prior to drop-film contact and during drop-film interactions. Understanding the air film dynamics underneath the droplet allows for the better tuning of the liquid film properties in the lubricating layer, designing more robust nanostructures, and ultimately enhancing the performance of liquid-infused surfaces for applications ranging from anti-fouling and anti-icing to phase separation and thermal management. Since the air film dissipation is a universal phenomenon, the outcome of this study is also relevant to many industrial processes such as multilayered inkjet printing of functional materials, spray coating on wetted surfaces, combustion of fuel in internal combustion engines, pesticide spraying on waxy plant leaves as well as cooling of microelectronics. The project is hence relevant to several research frontiers of fluid mechanics in conjunction with surface sciences, nanomanufacturing, and heat transfer. This project will also enable new course materials for PI's two recently developed courses on Interfacial Transport Phenomena and Nanomanufacturing, as well as original contributions to the Gallery of Fluid Motion at the American Physical Society Division of Fluids Dynamics Meetings. In addition to training graduate students, the PI will actively mentor undergraduate researchers and recruit women and under-represented minority students. The community outreach programs extend to inner-city K-12 teachers and students through the Philly Materials Day, Philly Science Festival, and Drexel Graduate Fellows in K-12 and Research for Undergraduate programs.The key objective of this study is to advance the fundamental understanding of drop impact on lubricated and liquid-infused surfaces, with a focus on probing the role of the entrained air layer between the drop and film both prior to liquid-liquid contact and during liquid-liquid interaction. In contrast to drop impact on solid surfaces where even the smallest asperities cause random breakup of the entraining air film, the air film failure mechanisms on lubricated surfaces are expected to be much more controllable. Moreover, the post-rupture liquid-liquid contact may lead to interfacial instability and microbubble formation whose mechanisms are unclear. By integrating the total internal reflection microscopy, reflection interference microscopy, and high-speed imaging, the air film evolution and post-rupture liquid-liquid contact dynamics will be directly visualized for different impact conditions and drop/film/substrate properties with nanometer spatial and microsecond temporal resolution. This unique capability enables direct probing of air film profile at thickness where the liquid-liquid intermolecular interactions become important. The knowledge obtained from this project will bridge the gap between the drop impact physics of solid surfaces to deep liquid pools and enable technological discoveries from surface structural design to enhanced lubricant stability. The specific project aims are to address the following issues as fundamental to drop impact on lubricated and liquid-infused surfaces: (1) How does the air film evolve and rupture with varying impact conditions, film properties, and ambient pressure? (2) What is the frontal growth dynamics of liquid-liquid contact after air film ruptures? (3) What is the mechanism of finger-like instability at the growing liquid-liquid front? (4) How do surface structures and inclination affect air entrainment and drop impact dynamics?

近年来，注入液体液体表面引起了人们的极大兴趣，因为它们的超级滑动特性在降低影响下，并且在自我清洁和防化应用中的潜在益处而没有太多了解基础物理学。拟议的项目旨在通过检查润滑和注入液体液的表面的下降冲击动态来解决此问题，重点是探测滴入式胶片接触之前和滴入式胶片相互作用之前所插入的空气层的作用。了解液滴下方的空气膜动力学可以更好地调整润滑层中的液体膜性能，设计更强大的纳米结构，并最终增强液体注入液体表面的性能，以用于抗污染，抗污染和抗染色以及相位分离到相位分离和热管理。由于空气膜的耗散是一种普遍现象，因此这项研究的结果也与许多工业过程有关，例如功能材料的多层喷墨印刷，在湿表面上喷涂涂料，内燃烧机中燃料的燃烧，在蜡质植物上喷洒农药的燃料以及微电机的冷却。因此，该项目与表面科学，纳米制造和传热的几个研究前沿相关。该项目还将为PI最近开发的有关界面运输现象和纳米制造的课程提供新的课程材料，以及在美国体液社会流体动力学会议上对流体运动画廊的原始贡献。除了培训研究生外，PI还将积极指导本科研究人员，并招募妇女和代表性不足的少数民族学生。在Philly Material Day，Philly Science Festival，Philly Science Festival和K-12中的Drexel毕业生中，社区宣传计划扩展到K-12的教师和学生，以及针对本科课程的研究。这项研究的关键目的是促进对润滑和液体液体液液的基本影响的基本了解，重点是在液体层之间进行液体层次的液体层次和液体层次的工作，并在液态下进行了液位的效果，并在液态下进行了效果。与对固体表面的影响下降相反，即使是最小的浅层也会导致插入空气膜随机破裂，因此预计润滑表面上的空气膜故障机制将更加可控。此外，破裂后液体液接触可能导致界面不稳定性和微泡形成，其机制尚不清楚。通过整合整个内部反射显微镜，反射干扰显微镜以及高速成像，将直接对不同的影响条件以及具有纳米表空间和微分时间分辨率的不同影响条件以及滴膜/膜/底物特性，直接对空气膜的演化和破裂后液体液体接触动力学进行直接可视化。这种独特的能力使得在厚度下直接探测空气膜的剖面，其中液 - 液中分子间相互作用变得很重要。从该项目中获得的知识将弥合固体表面的滴撞击物理学之间的差距到深液池，并从表面结构设计到增强的润滑剂稳定性。具体项目的目的是解决以下问题，这是对润滑和注入液体液体表面影响的基础：（1）空气膜如何随着影响条件，薄膜特性和环境压力而演变和破裂？ （2）空气膜破裂后液态液体接触的额叶生长动力学是什么？ （3）在生长的液体液体前部生长的手指样不稳定的机制是什么？ （4）表面结构和倾斜度如何影响空气夹带和落下影响动态？

项目成果

Air film contact modes of drop impact on lubricated surfaces under reduced pressures

减压下液滴冲击润滑表面的气膜接触模式

• DOI: 10.1063/5.0065747
• 发表时间: 2021
• 期刊: Physics of Fluids
• 影响因子: 4.6
• 作者: Zhang, Lige;Soori, Tejaswi;Rokoni, Arif;Kaminski, Allison;Sun, Ying
• 通讯作者: Sun, Ying

Learning new physical descriptors from reduced-order analysis of bubble dynamics in boiling heat transfer

从沸腾传热中气泡动力学的降阶分析中学习新的物理描述符

• DOI: 10.1016/j.ijheatmasstransfer.2021.122501
• 发表时间: 2022
• 期刊: International Journal of Heat and Mass Transfer
• 影响因子: 5.2
• 作者: Rokoni, Arif;Zhang, Lige;Soori, Tejaswi;Hu, Han;Wu, Teresa;Sun, Ying
• 通讯作者: Sun, Ying

Thin film instability driven dimple mode of air film failure during drop impact on smooth surfaces

• DOI: 10.1103/physrevfluids.6.044002
• 发表时间: 2021-04
• 作者: Lige Zhang;Tejaswi Soori;Arif Rokoni;Allison Kaminski;Ying Sun

The effect of particle wettability on the stick-slip motion of the contact line

• DOI: 10.1039/c8sm02129e
• 发表时间: 2018-12-21
• 期刊: SOFT MATTER
• 影响因子: 3.4
• 作者: Kim, Dong-Ook;Pack, Min;Sun, Ying
• 通讯作者: Sun, Ying