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

离子型表面活性剂的胶束水溶液在生物膜、脂肪消化、洗涤剂、石化工艺、化学催化等多种应用中发挥着重要作用。泡沫普遍存在，因为它们表现出一系列复杂、独特和有用的特性。该研究旨在为理解离子胶束溶液的泡沫稳定性和可成形性奠定科学和工程基础。获得全面的实验数据和发展的方法来描述吸附动力学和超分子力的离子表面活性剂是本研究的主要动机。另一个目标是找到启发式标准的可量化措施，如起泡性和泡沫稳定性，并将其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。泡沫包含薄膜和通道的复杂结构，在分子水平上，泡沫膜由表面活性剂稳定。胶束在泡沫膜中的分层导致分层，表现为逐步变薄和不同厚度的区域共存。分层有助于超分子振荡表面力的分离压力，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稳定性，定量分析电荷对由超分子结构力主导的表面张力和分离压的动态和平衡测量的影响。PI建议将起泡性与吸附动力学相关联，其特征在于使用PI组构建的最大气泡压力装置，并使用改进的薄膜平衡装置将泡沫稳定性与超分子结构力相关联。理论上的努力将集中在开发一个强大的自由能为基础的框架，用于量化的影响，吸附动力学和超分子结构力的电荷。一个集中的夏季实验研究计划，建议汇集在UIC的本科生团队进行软物质在接口领域的实验。由PI开发的名为“Fizzics和界面现象”的课程将作为研究生和本科生的跨学科选修课提供。Fizzics（或液滴、气泡、乳液和泡沫科学）、光学、流变学和复杂流体力学将构成外联活动的基础。参与的学生将开发几个低成本，强大的仪器，用于研究界面现象，并将提供给K-12教师。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.