Colloidal Films: Local Nanoparticle Self-Structuring and Novel Type of Detergency

美国国家科学基金会-化学与化工运输系统颗粒与多相过程分部计划(1415)摘要建议编号：CTS-0553738主要研究人员：瓦桑，达什市隶属关系：伊利诺伊理工学院建议标题：胶体膜：局部纳米粒子自结构和新型洗涤剂本建议是一项关于球形纳米粒子或表面活性剂胶束和溶剂组成的胶体流体的润湿和扩散现象的研究。胶体流体被限制在固体表面上的液膜的三相接触区域中。基础研究揭示了楔形薄膜内部的颗粒和/或胶束有序以及有序-无序结构转变的现象。智力价值拟议研究的目标是从实验和理论上阐明结构分离压力梯度(即薄膜张力梯度)在纳米流体在固体表面的润湿、扩散和粘合中的作用，并开发一种使用纳米颗粒的新型洗涤剂。将开展的具体任务包括：1)利用差示显微干涉法监测纳米流体在固体表面的扩散；2)利用激光扫描共聚焦显微镜和科塞尔衍射直接观察楔形薄膜中纳米流体的自组织；3)开发一种新型的纳米粒子去污剂；4)使用统计力学的积分方程法和蒙特卡罗模拟来模拟纳米流体的结构和扩散动力学。研究了影响纳米粒子结构形成和薄膜-弯月面区域结构分离压力的主要工艺因素，如粒子浓度、粒子电荷、粒子大小和多分散性。要研究的体系包括带电的和空间稳定的胶体颗粒，如二氧化硅和乳胶。扩散动力学将在玻璃、云母、硅片和塑料等各种表面上进行。广泛影响含有自组织结构的胶体膜的湿润，如纳米颗粒、聚合物乳液、球状蛋白质、表面活性剂胶束等的悬浮液在纳米技术和生物系统中都有重要的技术应用。例如，它们在固体表面的铺展和粘合行为可以产生具有理想结构和光学性能的材料。研究人员还试图通过为K-12年级科学教师开发胶体现象和去污剂的演示、研讨会和课程，以及IITs数学和科学教育部提供的继续教育项目，以及强调实践现象学方法的IITs科学和数学学习和提高倡议(SMILE)，有效地整合研究和教育。这些示范和课程也将纳入研究所针对高中生的推广方案，包括妇女参与科学和工程方案(WISE)。研究生和本科生将参与研究，短期的国际安置将加强他们的跨文化培训。

National Science Foundation - Division of Chemical &Transport Systems Particulate & Multiphase Processes Program (1415)ABSTRACTProposal Number: CTS-0553738Principal Investigator: Wasan, DarshAffiliation: Illinois Institute of TechnologyProposal Title: Colloidal Films: Local Nanoparticle Self-Structuring and Novel Type of DetergencyThis proposal is a study of the wetting and spreading phenomenon of a colloidal fluid comprising spherical nanosized particles or surfactant micelles and a solvent. The colloidal fluid is confined in a three-phase contact region of a liquid film on a solid surface. Fundamental research has revealed the phenomenon of particle and/or micelle ordering and order-disorder structural transitions inside the confined geometry of the wedge film. Intellectual MeritThe objectives of the proposed research are to elucidate, both experimentally and theoretically, the role of structural disjoining pressure gradient (that is, film tension gradient) in the wetting, spreading and adhesion of nanofluids on solid surfaces, and to develop a novel type of detergency using nanoparticles. The specific tasks to be undertaken are: 1) monitor spreading of nanofluids on solid surfaces using differential microinterferometry; 2) directly observe nanofluid self-structuring within wedge films using laser scanning confocal microscopy and Kossel diffraction; 3) develop a novel type of detergency using nanoparticles; and 4)model nanofluid structuring and spreading dynamics using the integral equation method of statistical mechanics and Monte Carlo simulations. Technological factors which greatly influence nanoparticle structure formation and thereby structural disjoining pressure in the film-meniscus region, such as particle concentration, particle charge, particle size, and polydispersity will be investigated. Systems to be investigated include charged and sterically stabilized colloidal particles, such as silica and latexes. The spreading dynamics will be carried out on various surfaces including glass, mica, silicon wafer and plastic.Broader ImpactWetting of colloidal films that contain self-organized structures, such as suspensions of nanoparticles, polymer latexes, globular proteins, surfactant micelles, etc. have significant technological applications in both nanotechnology and biological systems. For example, their spreading and adhesion behavior on solid surfaces can yield materials with desirable structural and optical properties. The researchers also seek to effectively integrate research and education by developing demonstrations, workshops, and lessons on colloidal phenomena and detergency for grades K-12 science teachers training and continuing education programs offered by IITs Department of Mathematics and Science Education, and IITs Science and Mathematics Initiative for Learningand Enhancement (SMILE) which emphasizes a hands-on phenomenological approach. These demonstrations and lessons will also be incorporated into IITs outreach programs for high school students including the Women in Science and Engineering Program (WISE). Graduate and undergraduate students will be involved in the research and short-term international placement will enhance their intercultural training.