Polymer-Based Capsules of Active Liquids Templated by Non-Aqueous Emulsions

非技术综述：科学家和工程师在电池、水净化、气体吸收等应用中不断开发性能提高的新材料。这些新材料为创造影响和改善现代生活几乎方方面面的新技术提供了基础。不幸的是，一些新材料，如离子液体和共晶溶剂，本身很难处理，它们需要某种形式的密封，限制了它们在实际系统中的使用。这项研究工作通过开发制备胶囊的方法来解决目前的这些限制，胶囊的核心是包裹在聚合物外壳中的特殊液体。这种方法是通过使用由分散在油中的活性液体的液滴组成的无水乳液，再加上聚合技术来实现的。不含水的乳液对开发这种封装系统至关重要，因为它们使专用液体保持纯净和未掺杂。这项工作解决了聚合物外壳的组成如何影响胶囊的性能特性，即机械性能和对气态二氧化碳的吸收。这项研究促进了复合材料领域的进步，并将其应用于能源储存和气体分离等关键领域。除了这项研究外，该项目还将支持本科生和研究生的培训以及如何制作视频。这些视频计划公开提供，并向新的研究人员展示如何使用科学仪器来表征基于聚合物的材料，从而支持更广泛的科学家和工程师的开发和培训。技术概述：计划研究的目标是开发以活性液体(如离子液体和深度共熔溶剂)为核心的胶囊和具有不同渗透性、稳定性和机械性能的聚合物复合材料外壳的制备方法。这将通过利用非水乳液中的界面聚合来实现。采用烷基化氧化石墨烯(GO)纳米片作为粒子表面活性剂稳定Pickering乳液，甲苯或辛烷为连续相，离子液体或深共晶溶剂为间断相。目的1以遥螺旋低聚物为单体，通过开环歧化聚合(ROMP)、可逆加成碎裂链转移聚合(RAFT)和自由基末端聚合(DEP)制备不同透气性和不同力学性能的胶囊壳。在目标2中，胶囊壳的稳定性将通过加入动态共价键来调节；这将使胶囊壳能够被破坏或融合。在目标3中，通过使用活性粒子表面活性剂和硫醇-烯化学，将使胶囊壳层厚度最小化，芯液纯度最大化。将确定胶囊的成分、形态、热性能、渗透性和机械性能。与Burcu Gurkan教授的一项没有资金支持的合作将揭示贝壳成分与气体二氧化碳渗透性之间的关系。与乔治·法尔教授的一项没有资金支持的合作将支持使用微操作技术对单个胶囊进行评估，产生力-位移曲线。科学研究得到了本科生和研究生研究人员的支持，以及演示用于表征软物质的技术的工作原理和实际考虑的How-to视频(HTV)。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARY:Scientists and engineers continue to develop new materials with improved performance in applications such as batteries, water purification, gas uptake, and so on. These novel materials provide the foundation used to create new technologies that impact and improve nearly every facet of modern life. Unfortunately, some of the new materials, such as ionic liquids and eutectic solvents, are difficult to handle by themselves, and they require containment of some kind, limiting their use in practical systems. This research work addresses these current limitations by developing methods to prepare capsules with cores of the specialized liquid wrapped in polymer shells. This approach is made possible by the use of a water-free emulsion that is composed of droplets of the active liquid dispersed in an oil, coupled with polymerization techniques. The water-free emulsions are critical to the development of this encapsulation system, as they allow the specialized liquid to remain pure and unadulterated. The work addresses how the composition of the polymer shell impacts performance properties of the capsules, namely mechanical properties and the uptake of gaseous carbon dioxide. This research promotes progress in the areas of composite materials with applications in critical areas such as energy storage and gas separations. In addition to the research, this project will support the training of undergraduate and graduate students and development of How-To Videos. These videos are planned to be publicly available and to show new researchers how to use scientific instruments to characterize polymer-based materials, thereby supporting the development and training of scientists and engineers more broadly. TECHNICAL SUMMARY:The goal of the planned research is to develop methods to prepare capsules with cores of active liquids (e.g., ionic liquids and deep eutectic solvents) and polymer composite shells of varied permeability, stability, and mechanical properties. This will be accomplished by leveraging interfacial polymerizations in non-aqueous emulsions. Alkylated graphene oxide (GO) nanosheets will be used as particle surfactant to stabilizing Pickering emulsions, toluene or octane will be used as the continuous phase, and ionic liquid or deep eutectic solvent as the discontinuous phase. Aim 1 focuses on preparing capsule shells of varied permeability and mechanical properties using telechelic oligomers as monomers, as prepared by ring opening metathesis polymerization (ROMP), reversible-addition fragmentation-chain transfer (RAFT) polymerization, and radical dead-end polymerization (DEP). In Aim 2, the stability of the capsule shell will be tuned by incorporation of dynamic covalent bonds; this will enable destruction or fusion of the capsule shells. In Aim 3, the capsule shell thickness will be minimized and the core fluid purity maximized by using reactive particle surfactants and thiol-ene chemistry. The capsule composition, morphology, thermal properties, permeability, and mechanical properties will be established. An unfunded collaboration with Prof. Burcu Gurkan will reveal the relationship between shell composition and permeability to gaseous CO2. An unfunded collaboration with Prof. George Pharr will support evaluation of individual capsules using micromanipulation techniques, producing force-displacement profiles. The scientific research is complemented by support of undergraduate and graduate researchers, as well as How-To Videos (HTVs) which demonstrate working principles and practical considerations for techniques used to characterize soft matter..This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.