Molecular-Scale Solutal Electrokinetics and Micro-Scale Control of Interfacial Phenomena in Ebullient Heat Transfer

CBET-0755720，ManglikThis研究是对表面活性剂（有机/合成单体，胶束和/或生物分子）的分子电动力学及其对界面现象（表面润湿和界面张力）的调制的基础多尺度研究，用于控制水溶液中的核沸腾和相关沸腾。 在分子尺度上，研究了气液界面上的加性分子动力学，以及气液界面上的物理吸附和电动力学。 这些过程进而影响液-气界面张力和固-液润湿的微观变化（其中由于试剂电动力学和分子流动性，两种通常互补的力现在可以解耦）。随后的变化，瞬态传输机制在池沸腾与其特征胚胎蒸汽成核和随后的气泡生长将进行研究。 此外，宏观尺度沸腾传热，宏观层界面传热，气泡生长及其动力学（聚结，崩溃，和翻译）将进行研究和建模，以便识别和关联沸腾控制（增强或抑制）参数。 在本质上，主要假设，液-汽界面张力和固-液表面润湿（主要决定因素的微观尺度成核和宏观尺度沸腾，因此沸腾控制预测）可以解耦和控制的分子吸附物理吸附，胶束动力学，电动力学的试剂在水溶液中将被建立，并预测相关性的发展。 智力优势：这项研究的结果将（i）推进界面现象的基础科学及其通过水溶液中表面活性剂的分子动力学进行的操纵，（ii）在建立表征核相变的液-固和液-气界面的微观机制方面具有洞察力，以及（iii）导致基础科学和工程的进步，以实现有效的被动控制技术，使用？设计？试剂（纳米尺寸的胶束链和表面活性剂样蛋白质基生物分子），用于成核相变沸腾和传热。 更广泛的影响：该项目将大大加强学生在跨流和跨学科工程科学的培训，提供先进的实验（国家的最先进的仪器）和数学/模拟分析的经验，并帮助生产高度积极的工程师和研究人员谁拥有知识的深度和广度，以及先进的研究和教育事业的技能。 将研究与教育结合起来，特别是让妇女和少数族裔工程专业学生参与进来，将进一步满足国家对培养更多样化的工程工作队伍的需求。此外，与工业和国家实验室合作伙伴的外联将有助于长期技术转让。 在更广泛的变革本质中，这项工作中发现的试剂分子动力学/电动力学调制的沸腾相变不仅是开发新型化学和生物传感器、微流体或芯片实验室设备、微尺度热交换器和天基系统的有效热管理的新前沿，而且还涉及可具有更广泛的跨学科应用的新型表面活性生物分子和胶束聚合物。

CBET-0755720, ManglikThis research is a fundamental multi-scale study of the molecular electrokinetics of surface-active agents (organic/synthetic monomers, micelles and/or biomolecules), and their modulation of interfacial phenomena (surface wetting and interfacial tension) for the control of nucleate boiling and associated ebullience in aqueous solutions. At the molecular-scale, the additive molecular dynamics at the liquid-vapor interface, and its physisorption and electrokinetics at the liquid-solid interface are to be investigated. These processes in turn affect micro-scale changes in liquid-vapor interfacial tension and solid-liquid wetting (where the two usually complimentary forces can now be decoupled due to the reagent electrokinetics and molecular mobility). The consequent changes in transient transport mechanisms during pool boiling with its characteristic embryonic vapor nucleation and subsequent bubble growth will be investigated. Also, the macro-scale ebullient heat transport, governed by macro-layer interfacial heat transfer, bubble growth and its dynamics (coalescence, collapse, and translation) will be studied and modeled, so as to identify and correlate boiling control (enhancement or suppression) parameters. In essence, the principal hypothesis that liquid-vapor interfacial tension and solid-liquid surface wetting (primary determinants of micro-scale nucleation and macro-scale ebullience, and hence boiling control predictors) can be decoupled and controlled by the molecular adsorption-physisorption, micellar dynamics, and electrokinetics of reagents in aqueous solutions would be established, and predictive correlations developed. Intellectual Merit: The findings of this study will (i) advance the fundamental science of interfacial phenomena and its manipulation by the molecular dynamics of surface-active agents in aqueous solutions, (ii) be insightful in establishing the micro-scale mechanisms at liquid-solid and liquid-vapor interfaces that characterize nucleate phase-change, and (iii) lead to the advancement of the fundamental science and engineering for an effective passive control technique, using ?designed? reagents (nano-sized micelle-chains and surfactant-like protein-based biomolecules), for nucleate phase-change ebullience and heat transfer. Broader Impact: This project will significantly enhance the training of students in cross-stream and inter-disciplinary engineering science, provide an experience in advanced experimentation (state-of-the-art instrumentation) and mathematical/simulation analysis, and help produce highly motivated engineers and researchers who have the depth and breadth of knowledge, and skills for advanced research and education careers. The integration of research with education, particularly involving women and minority engineering students, would further address the national need of training a more diverse engineering work force. Also, outreach with industrial and national laboratory partners will lend to long-term technology transfer. In a broader transformative essence, the reagent molecular dynamics/electrokinetics-modulated ebullient phase-change discovered in this work, is a new frontier in developing not only novel chemical and biological sensors, micro-fluidic or lab-on-chip devices, micro-scale heat exchangers, and effective thermal management of space-based systems, but also novel surface-active biomolecules and micellar polymers that may have a wider range of inter-disciplinary applications.