Tapered Block Copolymers: Interfacial Manipulation and Nanoscale Network Formation in Bulk and Thin Film Materials

随着未来技术进步需要设计和控制纳米级膜，必须完善用于创建具有可调形态、可加工性、传输性能和机械性能的定制材料的新方法。 不幸的是，许多设计系统需要在引入所需的化学成分和获得最佳的化学，运输和机械性能之间进行权衡。 为了克服这一困境，Epps小组正在开发界面改性的三嵌段共聚物系统，特别关注网络形成材料，通过使用组成锥度对内部（嵌段到嵌段）连接进行化学操作。 这些界面操作（锥形接头）将允许从自组装和热转变中解耦化学成分和分子量的影响，从而在设计这些软材料时提供更大的通用性。 这种三嵌段共聚物能够自组装成共连续网络结构，使它们成为纳米级器件的理想候选者。 三嵌段和锥形嵌段共聚物的组合可以产生具有改善的机械性能的高分子量网络系统（例如缠结的聚合物链），其中嵌段之间的锥形允许有效相互作用参数和纳米级界面混合的受控调节。 此外，通过开发对界面相互作用的更大控制，Epps小组将产生新的纳米结构材料，用于导电膜，分离膜和纳米级模板等应用。 这种控制将促进通用协议的开发，以生成用于体膜和薄膜纳米级应用的稳定、可加工和可调网络。 这种利用递变嵌段共聚物的纳米级网络也可能有助于替代能源、数据存储和生物应用。非技术总结：随着未来技术进步需要设计和控制纳米级膜，必须完善用于创建具有可调形态，加工性，传输性能和机械性能的定制材料的新方法。 不幸的是，许多设计系统需要在引入所需的化学成分和获得最佳的化学，运输和机械性能之间进行权衡。 为了克服这一困境，Epps小组正在开发化学合成方法，以控制膜材料中的纳米级（人类头发宽度的1/1000）界面，以允许独立调整这些化学，运输和机械性能。 通过使用特别改性的复杂聚合物，使纳米级界面的设计，合成和稳定化，用于分析分离膜，离子传导膜和纳米级模板的新材料可以开发用于替代能源，数据存储和生物应用。 此外，这个跨学科项目将培养学生解决纳米技术中的关键科学和工程挑战。 学生将探索化学、化学工程和材料科学的各个方面，使其处于纳米技术研究的最前沿。 与该项目直接相关的外展活动包括在Epps实验室为美国化学学会（ACS）少数民族学者计划本科生和ACS项目SEED（经济困难）高中生提供多学科夏季研究和导师机会。 PI一直积极参与涉及科学界代表性不足群体的活动，并将在整个项目期间继续这样做。

TECHNICAL SUMMARY:As future technological progress necessitates the design and control of nanoscale membranes, new methods for the creation of tailored materials with tunable morphology, processability, transport properties, and mechanical properties must be perfected. Unfortunately, many designer systems require a tradeoff between incorporating the desired chemical constituents and obtaining the optimal chemical, transport, and mechanical properties. To overcome this dilemma, the Epps group is developing interfacially-modified triblock copolymer systems, with a specific focus on network-forming materials, through the chemical manipulation of the internal (block-to-block) junctions using compositional tapers. These interfacial manipulations (tapered junctions) will allow decoupling of the influence of chemical constituents and molecular weight from self-assembly and thermal transitions, providing greater versatility in designing these soft materials. Such triblock copolymers are capable of self-assembling into co-continuous network structures, making them ideal candidates for nanoscale devices. The combination of triblocks and tapered block copolymers can produce high-molecular-weight network systems with improved mechanical properties (e.g. entangled polymer chains), where tapering between the blocks allows for the controlled tuning of effective interaction parameters and nanoscale interfacial mixing. Further, by developing greater control over interfacial interactions, the Epps group will generate new nanostructured materials for applications such as conducting membranes, separation membranes, and nanoscale templates. This control will facilitate the development of universal protocols for the generation of stable, processable, and tunable networks for bulk membrane and thin-film nanoscale applications. Such nanoscale networks utilizing tapered block copolymers may also be helpful for alternative energy, data storage, and biological applications. NON-TECHNICAL SUMMARY:As future technological progress necessitates the design and control of nanoscale membranes, new methods for the creation of tailored materials with tunable morphology, processability, transport properties, and mechanical properties must be perfected. Unfortunately, many designer systems require a tradeoff between incorporating the desired chemical constituents and obtaining the optimal chemical, transport, and mechanical properties. To overcome this dilemma, the Epps group is developing chemical synthesis methods to control the nanometer scale (1/1000th the width of a human hair) interfaces in membrane materials to permit the independent tuning of those chemical, transport, and mechanical properties. By using specially modified complex polymers to enable the design, synthesis, and stabilization of nanoscale interfaces, novel materials for analytical separation membranes, ion-conduction membranes, and nanoscale templates may be developed for alternative energy, data storage, and biological applications. Additionally, this interdisciplinary project will train students to address key scientific and engineering challenges in nanotechnology. Students will explore aspects of chemistry, chemical engineering, and materials science, placing them at the forefront of nanotechnology research. Outreach activities directly related to the project include providing multidisciplinary summer research and mentorship opportunities in Epps' labs for American Chemical Society (ACS) Minority Scholars Program undergraduates and ACS Project SEED (economically-disadvantaged) high school students. The PI has been active in activities involving underrepresented groups in science and will continue to do so throughout this project.