GOALI: Balanced Surfactants for Self-Assembly of Highly Immiscible Polymers

Nitash Balsara-加州大学伯克利分校David Lohse-ExxonMobilGOALI：用于高度不相容聚合物自组装的平衡表面活性剂拟议活动的智力优点拟议工作的目标是建立一个表面活性剂库，用于控制高度不相容聚合物混合物的自组装。这将使创造新的纳米结构聚合物材料成为可能。它还可以重新利用混合的聚合物废物。该方法不同于以往在该领域的大量实验和理论工作，这些工作依赖于A-B共聚物的表面性质来组织A和B均聚物的混合物。现在人们认识到，只有当均聚物弱不相容时，这些类型的共聚物才能组织界面。将在研究中使用的表面活性剂是一种平衡的A-C嵌段共聚物。平衡的概念取自有关水体系中表面作用的文献。非离子表面活性剂具有疏水和亲水平衡的特性，尽管它们具有高度的不相容性质，但仍成功地在油水混合物中形成了纳米结构。这项研究涉及到这一原理在聚合物中的应用。实验将在高度不相容的聚烯烃、聚丁烯(PB)和聚异丁烯(PIB)的混合物上进行。聚丁烯-嵌段-乙烯-丁烯共聚物(PB-EB)将作为表面活性剂。该体系是基于PB/EB和PIB/EB Flory-Huggins相互作用参数的温度依赖性而选择的。预计表面活性剂的亲PIB和憎恶PIB倾向的平衡将导致丰富的相行为，到目前为止，只有在水混合物中才能确定这些行为。然而，正在开发的平衡原理是完全通用的，可以应用于各种聚合物混合物。本研究所需的模型聚合物将通过阴离子聚合和阳离子聚合来合成。自组装将在国家标准与技术研究所(NIST)通过小角中子散射、光散射和电子显微镜进行研究。拟议活动和目标机制的广泛影响从事此项目的学生将由PI(加州大学伯克利分校)和共同PI(埃克森美孚)联合提供建议。这名学生每年将在新泽西州安南代尔的埃克森美孚企业研究实验室工作约6周。与访问相关的所有费用(住宿、旅费、实验室用品等)将由埃克森美孚支付。这种合作的框架已经建立：这位博士生在去年夏天花了两周时间在埃克森美孚，学习聚合物合成，并获得了安全培训和埃克森美孚实验室的工作许可。接触工业研究实验室将为学生的教育增加一个新的维度。由于该项目将涉及对NIST的多次访问，学生将了解政府实验室的运作情况。将合成和表征的材料和样品将用于伯克利大学热力学和聚合物科学课程的教学，以及NIST等其他机构的教学。

Nitash Balsara - University of California - BerkeleyDavid Lohse - ExxonMobilGOALI: Balanced Surfactants for Self-Assembly of Highly Immiscible PolymersIntellectual Merit of Proposed ActivityThe objective of the proposed work is to build a library of surfactants for controlling the self-assembly in mixtures of highly immiscible polymers. This will enable the creation of newnanostructured polymer materials. It may also enable reusing commingled polymeric waste. The approach represents a departure from the large body of previous experimental and theoretical work in this field which relied on the surfactancy of A-B copolymers for organizing mixtures of A and B homopolymers. It is now recognized that these types of copolymers can only organize interfaces if the homopolymers are weakly immiscible. The surfactant that will be used in the research is a balanced A-C block copolymer. The notion of balance is adapted from the literature on surfactancy in aqueous systems. Nonionic surfactants with balanced hydrophobic and hydrophilic character have been successful in creating nanoscale organization in oil/water mixture in spite of their high degree of incompatibility. The reseserch deals with the application of this principle to polymers. Experiments will be conducted on mixtures of highly immiscible polyolefins, polybutene (PB) and polyisobutylene (PIB). Polybutene-block-ethylenebutene copolymer (PB-EB) copolymer will serve as the surfactant. This system was chosen on the basis of the temperature dependence of the PB/EB and PIB/EB Flory-Huggins interaction parameters. It is expected that the balancing of PIB-philic and PIB-phobic tendencies of the surfactant will lead to the rich varieties of phase behaviors that have, thus far, only been identified in aqueous mixtures. The principle of balance that is being developed is, however, perfectly general, and can be applied to a wide variety of polymer blends. Model polymers required for this study will be synthesized by anionic and cationic polymerization. Self-assembly will be studied by small angle neutron scattering at the National Institute of Standards and Technology (NIST), light scattering, and electron microscopy.Broader Impact of Proposed Activity and GOALI mechanismThe student working on this project will be jointly advised by the PI (at UC Berkeley) and co-PI (at ExxonMobil). The student will spend about 6 weeks every year, working at the ExxonMobil Corporate Research Labs in Annandale, NJ. All of the expenses associated with the visit (lodging, travel, lab supplies, etc.) will be paid by ExxonMobil. The framework for this collaboration has already been established: the PhD student spent 2 weeks this past summer at ExxonMobil, learning about polymer synthesis, and obtaining safety training and clearances to work in the ExxonMobil Labs. Exposure to an industrial research lab will add a new dimension to the student's education. Since the project will involve several visits to the NIST, the student will learn about the functioning of government laboratories. The materials and samples that will be synthesized and characterized will be used in teaching courses on both thermodynamics and polymer science at Berkeley, and at other institutions such as NIST.