Colloidal Transport, Self-Assembly, and Deposition in Evaporating Droplets

蒸发液滴中的胶体传输、自组装和沉积

• 批准号: 2344217
• 负责人: Hassan Masoud
• 金额: $ 34.74万
• 依托单位: Michigan Technological University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-04-15 至 2027-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2344217&HistoricalAwards=false
• 关键词: Colloidal; Transport; Self; Assembly; Deposition

From beverage marks on the kitchen table to salt deposits on windows of the family car, we are all familiar with these stains that plague our homes and vehicles. However, such residues are not in random nor uniform patterns, and they often appear as circular spots with a bright center and a dark rim. A closer inspection of this phenomenon reveals that the accumulation of the particles at the edge is facilitated by the fluid flow inside the droplet, which is, in turn, driven by the liquid leaving the free surface of the drop due to evaporation. Apart from its everyday relevance, the evaporation-driven deposition of solutes offers a simple, inexpensive method for assembling complex miniature structures. This method can also be used as a diagnostic tool for forensic analysis, disease examination, and biodetection. The goal of this award is to examine the motion of particles suspended in evaporating colloidal droplets that rest on a substrate, and to link the transport of the colloids to where they finally reside when the droplet is desiccated. The planned studies are coupled with a range of educational activities that involve outreach to underrepresented middle and high school students, mentorship of diverse community college and graduate students, and curriculum development.This award aims to investigate the transport and aggregation of nonvolatile particles in drying colloidal sessile drops with the ultimate goal of understanding the mechanisms underlying various deposition patterns. Specifically, high-fidelity numerical simulations and theoretical analyses will be used to study the (i) role of the liquid-gas interface in the evolution of the evaporative self-assembly process, (ii) impact of shape and polydispersity on transport and deposition of solutes, and (iii) sensitivity of particle transport and deposition to droplet geometry and shielding effect. The findings of this award will narrow the gap in our current knowledge and fundamental understanding of the evaporation-induced transport, self-assembly, and deposition of particles initially suspended in a sessile drop of a simple liquid. They will also establish a transformative physics-based regime map for deposition patterns that can serve as an engineering guideline for tailoring the system parameters in order to elicit the desired self-assembled structure for a variety of high-tech applications. The map can also be utilized as a diagnostic tool for pinpointing the properties of the suspended particles and the nature of their interactions with themselves, with the liquid-gas interface, and with the substrate.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.

从厨房桌子上的饮料标记到家庭汽车窗户上的盐沉积，我们都熟悉困扰我们房屋和车辆的这些污渍。但是，这些残基不是随机或均匀的图案，它们通常是圆形的斑点，具有明亮的中心和黑暗的边缘。对这种现象的仔细检查表明，边缘颗粒的积累是由液滴内部的流体流动促进的，这又是由液体驱动的。除了日常相关性外，蒸发驱动的溶质沉积还提供了一种简单，廉价的方法来组装复杂的微型结构。该方法也可以用作法医分析，疾病检查和生物调查的诊断工具。该奖项的目的是检查悬浮在蒸发基板上的胶体液滴中的颗粒的运动，并将胶体的传输与液滴干燥时最终驻留的位置联系起来。计划的研究与一系列教育活动相结合，这些活动涉及对代表性不足的中学生和高中生，多元化社区学院和研究生的指导以及课程的发展。该奖项旨在调查在理解各种动力范围的最终基础上，研究非挥发性壳的非挥发性小子的运输和聚合，以了解各种疾病。具体而言，高保真数值模拟和理论分析将用于研究液体界面在蒸发自组装过程演化中的（i）（ii）形状和多分散性对溶质的传输和降低的影响（ii）对溶质的运输和（iii）对液压和液滴的粒子运输和沉积液的敏感性的影响。该奖项的发现将缩小我们当前的知识和对蒸发引起的运输，自组装和沉积颗粒的沉积的基本理解，最初悬浮在简单液体的无柄下降中。他们还将为沉积模式建立一个基于变革性的物理制度图，该制度模式可以用作定制系统参数的工程指南，以便为各种高科技应用程序引起所需的自组装结构。该地图也可以用作诊断工具，用于指出悬浮颗粒的特性以及与液态加气接口以及基质的互动性质，并具有基质。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子和更广泛的影响来评估的，并被认为是值得的。