Nanoparticles as Surfactants: Static and Dynamic Properties

0932259 Leal“该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。“多相聚合物体系中共聚物和聚合物官能化纳米颗粒的界面活性具有深刻的科学兴趣和巨大的工业重要性。除了它们提出的各种基础科学问题外，这些合成增容剂还能使不混溶聚合物共混。此外，功能化纳米颗粒的核材料可以提供额外的化学或物理功能（磁性、光学、热或电子）。然而，即使是对它们如何工作的基本了解也仍然缺乏。该研究旨在测量、预测和建模纳米颗粒和共聚物表面活性剂的静态和动态性质。如果没有这种能力进行这样的测量，从而发展一个基本的了解他们的操作，合理的设计合成相容剂先进的聚合物共混物将仍然是不可能的。拟议项目的核心智力价值是开发和应用新技术来测量和理解聚合物/聚合物界面处合成共聚物和纳米颗粒“表面活性剂”的静态和动态特性，这基本上是第一次。这需要实现三个具体目标：（1）开发新的微尺度技术和工具。发展了两种新的测量技术：微张力仪和主动微流变技术，用于测量相容剂负载界面的表面粘弹性和非线性粘度;（2）利用这些新的测量工具测量和表征纳米粒子和共聚物表面活性剂的静态和动态。具体而言，将测量纳米颗粒和共聚物表面活性剂的表面压力与浓度等温线、表面活性剂扩散率和界面粘弹性，其性质以系统和全面的方式变化;以及（3）开发捕获测量行为的理论并进行可测试的预测;以便推广我们的结果，提供对这些合成相容剂工作机制的直观理解，并指导设计规则。拟议的工作具有潜在的高度变革性：它不仅提出开发新颖和前所未有的测量能力，而且还提出对共聚合物和纳米颗粒表面活性剂的静态和动态行为的基本和一般理解，以及如何设计它们的直觉。拟议工作的广泛影响相当大。首先，要开发的测量工具只需要少量的样品，但将能够控制界面组成和测量界面张力和流变性，这将是前所未有的。拟议工作的这一方面将在提供信息方面真正起到变革作用。具体的测量将是第一次，并将允许第一步的静态和动态性质的纳米粒子表面活性剂在聚合物/聚合物界面的基本理解。这样的理解也可能是变革性的，因为它将使具有所需性能的先进聚合物材料的合理设计和加工成为可能。这些团体将继续积极招募和指导有代表性的少数民族学生和雄心勃勃的本科生参加夏季和学年研究项目，利用UCSB材料研究实验室的国家认可的外联基础设施。一名高中教师将参与暑期研究，以影响他/她自己的经验以及他/她的学生在未来几年。为了接触到更广泛的大学社区，将为非理科学生开发一个新生研讨会课程，内容涉及日常生活中熟悉的流变学有趣产品的科学和工程，包括食品和个人护理产品。这个想法是让学生接触到有趣的，无处不在的和令人惊讶的理解世界的材料，既不是固体也不是液体。作为本课程的一部分，研究人员将在互联网上免费发布课堂讲稿和演示视频;在其成功开发之后，我们将为化学工程教育撰写一篇描述性文章，以鼓励和促进其他本科或高中课程的相关课程内容。

0932259Leal"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."The interfacial activity of copolymers and polymer functionalized nanoparticles in multiphase polymer systems holds deep scientific interest and enormous industrial importance. In addition to the variety of basic science questions they raise, these synthetic compatibilizers enable blends of immiscible polymers. Moreover, the core material of functionalized nanoparticles may offer additional chemical or physical functionality (magnetic, optical, thermal or electronic). However, even a basic understanding of how they work remains lacking. The research aims to measure, predict, and model the static and dynamic properties of nano-particle and co-polymer surfactants. Without such capability to make such measurements, and thus to develop a fundamental understanding of their operation, the rational design of synthetic compatibilizers for advanced polymer blends will remain impossible.Intellectual merit. The central intellectual merit of the proposed project is to develop and apply new techniques to measure and understand the static and dynamic properties of synthetic co-polymer and nanoparticle "surfactants" at polymer/polymer interfaces, essentially for the first time. This requires three specific aims be achieved:(1) To develop novel micro-scale techniques and tools. Two new and novel techniques will be developed: a micro-tensiometer, and an active microrheology technique to measure the surface viscoelasticity and nonlinear viscosity of the compatibilizer laden interface; (2) To use these new tools to measure and characterize the statics and dynamics of nanoparticle and copolymer surfactants. Specifically, surface pressure vs. concentration isotherms, surfactant diffusivity and interfacial viscoelasticity will be measured for nanoparticle and copolymer surfactants, whose properties are varied in a systematic and comprehensive manner; and (3) To develop theories that capture the measured behavior and make testable predictions; so as to generalize our results, provide an intuitive understanding of the mechanisms by which these synthetic compatibilizers work, and guide design rules. The proposed work is potentially highly transformative: not only does it propose to develop novel and unprecedented measurement capabilities, but also to develop fundamental and general understanding of the static and dynamic behavior of copolyer and nanoparticle surfactants, as well as intuition for how to design them.Broader impact. The broader impact of the proposed work is quite substantial. First, the measurement tools to be developed require only minute quantities of sample, yet would enable a control over interfacial composition and the measurement of interfacial tension and rheology, that would be unprecedented. This aspect of the proposed work would be truly transformative in terms of the information it would make accessible. The specific measurements would be the first of their kind, and would allow the first steps toward a fundamental understanding of the static and dynamic properties of nano particle surfactants at polymer/polymer interfaces. Such understanding would be potentially transformative as well, in that it that would enable the rational design and processing of advanced polymeric materials with desired properties. The groups will continue to be active in recruiting and mentoring under represented minority students and generally ambitious undergraduates in summer and academic year research projects, by leveraging the nationally recognized outreach infrastructure in UCSB's Materials Research Laboratory. A high school teacher will be involved in summer research, to impact his/her own experience as well as his/her students in future years. To reach out to the broader university community, a freshman seminar course will be developed for non-science students on the science and engineering of rheologically interesting products familiar from everyday life including foods and personal care products. The idea is to expose students to the interesting, ubiquitous and surprisingly understandable world of materials that are neither solid nor liquid. As part of this course, the investigators will post lecture notes and demonstration videos freely on the internet; following its successful development, we will write a descriptive article for Chemical Engineering Education, to encourage and facilitate related course content for other undergraduate or high school programs.