Foamability of Ionic Micellar Solutions: Adsorption Kinetics and Supramolecular Surface Forces

离子表面活性剂胶束水溶液在生物膜、脂肪消化、洗涤剂、石油化工、化学催化等领域有着广泛的应用。这项拟议的研究旨在为了解离子胶束溶液的泡沫稳定性和成型性奠定科学和工程基础。获得全面的实验数据和发展描述离子表面活性剂的吸附动力学和超分子作用力的方法是本研究的主要动机。另一个目标是找到可量化的启发式标准，如发泡性和泡沫稳定性，并将它们与表面活性剂的物理化学性质相关联，以帮助发现更好的表面活性剂，包括可生物降解的生物表面活性剂。泡沫包含复杂的薄膜和通道结构，在分子水平上，泡沫膜由表面活性剂稳定。泡沫膜中胶束的分层导致分层，表现为逐步变薄和不同厚度区域的共存。分层对分离压力产生超分子振荡表面力，从而影响泡沫膜的稳定性。实验和理论研究的重点是了解离子表面活性剂的吸附动力学和泡沫膜的稳定性，定量分析电荷对超分子结构作用力主导的表面张力和分离压力的动态和平衡测量的影响。PI建议通过使用PI基团建立的最大气泡压力装置和泡沫稳定性来将发泡性与吸附动力学关联起来，并使用改进的薄膜平衡装置来关联超分子结构力。理论工作将集中于开发一个基于自由能的强大框架，用于量化电荷对吸附动力学和超分子结构力的影响。一项有重点的夏季实验研究计划被提议聚集在UIC的一个本科生团队中，在界面软物质领域进行实验。一门名为“泡沫和界面现象”的课程将作为一门跨学科选修课提供给研究生和本科生。泡沫学(或水滴、气泡、乳液和泡沫的科学)、光学、流变学和复杂流体的力学将构成外展活动的基础。参与的学生将开发几种低成本、坚固的工具来研究界面现象，并将向K-12教师提供这些工具。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Aqueous micellar solutions of ionic surfactants play a significant role in diverse applications including biological membranes, fat-digestion, detergents, petrochemical processes, chemical catalysis, etc. Foams are ubiquitous as they exhibit a range of complex, unique and useful properties. The proposed research aims to develop the scientific and engineering foundations for understanding foam stability and formability of ionic micellar solutions. Obtaining comprehensive experimental data and developing methods for describing adsorption kinetics and supramolecular forces for ionic surfactants are primary motivations for this study. Another goal is to find quantifiable measures of heuristic criteria like foamability and foam stability and correlate them to physicochemical properties of surfactants to aid in the discovery of better surfactants, including biodegradable bio-surfactants.Foams contain a complex architecture of thin films and channels, and, at the molecular level, foam films are stabilized by surfactants. Layering of micelles in foam films results in stratification, manifested as stepwise thinning and coexistence of regions with different thicknesses. The layering contributes supramolecular oscillatory surface forces to disjoining pressure, that influence the stability of foam films. The proposed experimental and theoretical research focuses on understanding the adsorption kinetics and foam film stability of ionic surfactants, to quantitatively analyze the influence of charge on dynamical and equilibrium measurement of surface tension and disjoining pressure dominated by supramolecular structural forces. The PI proposes to correlate foamability to adsorption kinetics characterized by using maximum bubble pressure apparatus built by the PI's group and foam stability to supramolecular structural forces using a modified thin film balance apparatus. The theoretical effort will focus on developing a robust free-energy based framework for quantifying the influence of charge on both adsorption kinetics and supramolecular structural forces. A focused summer experimental research initiative is proposed to bring together a team of undergraduate students at UIC to conduct experiments in the realm of soft matter at interfaces. A course titled 'Fizzics and Interfacial Phenomena', developed by the PI, will be offered as an interdisciplinary elective to graduate and undergraduate students. Fizzics (or the science of drops, bubbles, emulsions and foams), optics, rheology and mechanics of complex fluids will form the basis for outreach activities. The participating students will develop several low-cost, robust instruments for studying interfacial phenomena and will make the instruments available to K-12 teachers.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.