Liquid-Core Capsules via Interfacial Free Radical Alternating Copolymerization

研究：液芯胶囊在药物、染料、酶等的高效包埋和控制输送方面的应用推动了创新技术的快速发展，这些技术基于层层组装、粒子和树枝状大分子的壳聚合，然后去核、核-壳乳液和囊泡的微相分离，从而限制了包封剂在界面的聚合或组装。然而，所有这些技术都以这样或那样的方式需要程序和材料，例如反复离心-洗涤、烧结、去核、微相分离、囊泡模板或嵌段共聚物，限制了对壳层厚度和渗透性的控制，阻碍了对基质的直接包覆，或者阻碍了大规模的实际应用。本项目的目的是研究界面自由基交替共聚，直接将液滴包裹在聚合物外壳内，而不需要固体核或泡囊模板。制造液芯胶囊的方法是基于自由基类比界面冷凝原理，通常用尼龙绳技巧来演示。与接触时反应失控的二胺和二酸氯化物不同，油溶和水溶的乙烯基醚和马来酸烷基酯通过自由基机制在界面上交替共聚。这项工作的目的是：1.阐明在界面聚合过程中形成液核胶囊的机理2.展示水核胶囊壳层渗透性的动态控制这种聚合的基本原理和方法允许通过高度可扩展和廉价的过程直接包裹许多底物。界面自由基交替共聚的一般原理具有潜在的重大影响，不仅限于液核胶囊，还延伸到许多成熟的纳米技术中，其中界面的优势突出了界面聚合的重要性。更广泛的影响：这个项目的更广泛的影响包括介绍、教育和培训高中、本科生和研究生关于自由基和缩合聚合原理、界面现象和复杂流体的知识。将特别努力招收美国学生和少数民族学生继续深造。特别是，工程教育将通过加州大学旨在从辛辛那提市大量黑人人口中招收学生的计划向代表性不足的群体推广。本文提出的形成液核胶囊的自由基聚合方法，由于其低成本和易于大规模实施，从商业角度来看，本身就具有广泛的影响。

ABSTRACTPI: Carlos C. Co and Chia-Chi Ho Institution: University of CincinnatiProposal Number: 0457453Title: Liquid-Core Capsules via Interfacial Free Radical Alternating CopolymerizationResearch: Liquid-core capsules have application in the high efficiency encapsulation and controlled delivery of drugs, dyes, enzymes, etc. These applications have driven the rapid development of innovative techniques, based on layer-by-layer assembly, shell polymerization of particles and dendrimers followed by core-removal, microphase separation of core-shell latexes, and vesicles, to confine polymerization or assembly of encapsulants at the interface. However, all of these techniques require, in one way or another, procedures and materials, such as repeated centrifugation-washing, sintering, core-removal, microphase separation, vesicle templates, or block copolymers, that limit control of shell thickness and permeability, preclude direct encapsulation of substrates, or hamper large-scale practical application. The aim of this project is to study interfacial free-radical alternating copolymerization for direct encapsulation of liquid drops within a polymer shell without the need for a solid core or vesicle template. The approach for making liquid-core capsules is based on a free-radical analogy of interfacial condensation principles routinely demonstrated with the nylon rope trick. Instead of diamines and diacid chlorides that react uncontrollably upon contact, oil- and water-soluble vinyl ethers and alkyl maleates are alternately copolymerized at interfaces via a free-radical mechanism. The objectives of the work are to: 1.Elucidate the mechanism through which liquid-core capsules are formed during interfacial polymerization 2. Demonstrate dynamic control of shell permeability for aqueous-core capsules The underlying principles and methodology of this type of polymerization allows for the direct encapsulation of many substrates through a highly scalable and inexpensive process. The general principle of interfacial free-radical alternating copolymerization has potentially significant impacts that extend beyond liquid-core capsules and into many established nanotechnologies where the preponderance of interfaces accentuates the significance of interfacial polymerizations. Broader Impacts: Broader impacts of this project include the introduction, education, and training of high school, undergraduate, and graduate students in the principles of radical and condensation polymerizations, interfacial phenomena, and complex fluids. Special effort will be made to recruit American and minority students to pursue advanced studies. In particular, engineering education will be promoted to under-represented groups via UC programs aimed at recruiting students from the large black population in the city of Cincinnati. The free-radical polymerization approach to liquid-core capsule formation proposed here, itself promises broad impact from a commercial standpoint due to its low cost and the ease with which it can be implemented on a large scale.