CAREER: Dynamic Simulations of Reconfigurable Complex Fluids From "Janus" and "Catalytically-Driven" Colloidal Particles

科尔多瓦1055284这份职业发展计划结合了PI在低雷诺数流体力学和胶体悬浮液方面的专业知识，研究基于双面贾纳斯颗粒悬浮液的新兴复杂流体领域-具有两个不同侧面的颗粒-取决于其表面功能可能导致新的材料特性、聚集/自排序能力，或使用远离平衡运行的车载化学发动机的自主行为。研究和教育活动旨在阐明可重构复杂流体的重要方面-使用Janus和催化驱动的胶体颗粒作为前体的活性材料可以在最少或没有外部干预的情况下改变和松弛其结构。研究工作分为两个主要任务。第一个重点是研究在流体流动和外力的共同作用下，Janus颗粒悬浮液的运动、流变性和结构组织。根据粒子的Janus面之间的粒子间力(例如，硬球、有吸引力、软)，预期会有不同的行为。第二个研究任务旨在了解催化驱动的Janus粒子悬浮液的集体运动。在经典的多组分扩散和耗尽絮凝理论的基础上，将使用和实施一种通过化学反应实现自主运动的简单胶体方法。简单的基本动态单元以特定的规则运行并利用趋化性，将被建议作为未来可重构材料的元素。这些努力将通过布朗/斯托克动力学模拟和与合作伙伴的实验来完成。该计划的教育和宣传部分旨在让从K-12到研究生的拉美裔人参与和接受教育。将开设一门关于各向异性胶体悬浮液中粒子动力学的研究生课程。胶体流体力学的新兴主题将被纳入现有的本科流体力学课程。将使用先进的多媒体技术开发和实现说明自动移动的Janus粒子的模块。其他教育活动包括举办工作坊，帮助学生加强沟通技巧，改善他们为研究生入学考试(GRE)所作的准备。智力价值：这项工作将提供对迄今为止缺失的不对称功能化胶体颗粒的基本了解，这一缺乏迄今阻碍了Janus颗粒技术的充分开发和使用--通过改进材料、传感器和药物输送。测量它们在不同颗粒浓度和流动条件下的流变行为将为各向异性胶体的研究提供坚实的基础、基本的工具和可应用于这些技术的加工和使用的知识，从而对各向异性胶体的研究产生广泛的影响。另一方面，对Janus粒子催化驱动运动的研究将导致发现有趣的材料特性和行为，如合成趋化性和捕食者-猎物合作运动，这些通常在自然界中存在。该研究计划旨在利用布朗/斯托克动力学模拟对催化驱动的粒子运动提供必要的询问，特别是在具有实验挑战性的条件下(例如，集中量、有限的控制量)。提出了基于催化驱动运动的动力学单元的简单模型，可用于可重构复杂流体的设计和合成。更广泛的影响：这项研究将对几个科学和技术界产生重大影响，包括胶体和复杂流体、微流体和中间相物理学。综合研究/教学计划将教授和培训与胶体科学和工程学有关的代表人数不足的学生。该项目的所在地--波多黎各-马亚格斯大学(UPRM)--将促进来自代表性不足群体的学生的参与和教育。该项目的教学和宣传部分涉及胶体流体力学、工程材料和运输现象方面的倡议。

Cordova 1055284 This CAREER development plan combines the expertise of the PI in low Reynolds number hydrodynamics and colloidal suspensions to study the emerging field of complex fluids based on suspensions of two-faced Janus particles - particles which have two distinct sides - that depending on their surface functionality could lead to novel material properties, aggregation/self-ordering abilities, or to autonomous behaviors using on-board chemical motors operating far from equilibrium. Research and educational activities are designed to elucidate important aspects of reconfigurable complex fluids - active materials that could change and relax their structure with minimum or no external intervention using as precursors Janus and catalytically-driven colloidal particles. The research efforts are divided in two main tasks. The first one focuses on studying the motion, rheology, and structural organization of Janus particle suspensions guided by a combination of fluid flows and external forces. Different behaviors are expected depending on the interparticle force between the Janus faces of the particles (e.g., hard sphere, attractive, soft). The second research task aims at understanding collective motion of catalytically-driven Janus particle suspensions. A simple colloidal approach to autonomous motion via chemical reactions will be used and implemented based on classic multicomponent diffusion and depletion flocculation theory. Simple elementary dynamic units operating with specific rules and exploiting chemotaxis will be proposed as elements for future reconfigurable materials. These efforts will be accomplished by Brownian/Stokesian dynamics simulations and experiments with collaborating partners. The education and outreach components of the plan aim to involve the participation and education of Hispanics from the K-12 to the graduate level. A graduate course in particle dynamics in anisotropic colloidal suspensions will be developed. Emerging topics in colloidal hydrodynamics will be incorporated into an existing undergraduate fluid mechanics course. Modules illustrating autonomously-moving Janus particles will be developed and implemented using advanced multimedia techniques. Additional education activities include workshops to help students strengthen their communications skills and improve their preparation for the Graduate Record Examination (GRE). Intellectual Merit: This work will provide a level of fundamental understanding of asymmetrically functionalized colloidal particles that has heretofore been missing, a lack which has thus far prevented the full development and use of Janus particle technologies - by leading to improved materials, sensors, and drug delivery. The measurement of their rheological behavior at different particle concentrations and flow conditions will broadly impact research on anisotropic colloids by providing a solid basis, basic tools, and knowledge that can be applied in the processing and use of these technologies. On the other hand, the study of catalytically-driven motion of Janus particles will lead to the discovery of interesting material properties and behaviors, such as synthetic chemotaxis and predator-prey cooperative motions that are usually found in nature. The research plan aims at providing a necessary interrogation of catalytically-driven particle motion using Brownian/Stokesian dynamics simulations, particularly at conditions challenging to address experimentally (e.g., concentrated quantities, limited control volumes). Simple models of dynamic units based on catalytically-driven motion that could be exploited for the design and synthesis of reconfigurable complex fluids are proposed. Broader Impact: The research will substantially impact several scientific and technological communities including colloids and complex fluids, microfluidics and physics of interphases. The integrated research/teaching plan will teach and train underrepresented students in topics related to colloidal sciences and engineering. The site of the project, University of Puerto Rico-Mayagüez (UPRM), will facilitate the participation and education of students from underrepresented groups. The teaching and outreach components of the project involve initiatives in colloidal hydrodynamics, engineering materials, and transport phenomena.