Understanding Structure and Response in Thermally-Responsive Block Copolymer Assemblies

响应性聚合物组装体在一系列应用中显示出巨大的前景，包括药物递送、传感和催化。对这些系统的阐述至关重要的是聚合物的发展，这些聚合物在具有不同尺寸和结构的组件之间经历快速，可预测和可逆的变化。对于涉及在聚合物囊泡内包封其他物质的应用，开发更有效的包封方法也非常重要。为了应对这些挑战，PI及其同事先前制备了温度响应性ABC三嵌段共聚物，（环氧乙烷）（PEO）作为亲水性嵌段，聚（N-异丙基丙烯酰胺）作为温度响应性嵌段，和聚异戊二烯作为交联疏水嵌段，它们形成在临界温度附近经历大的尺寸和形状变化的组件，然而，发现在高温下将小的组装体（直径为20 nm的胶束）重组成较大的组装体（直径为100 nm的囊泡）需要几周时间。最近，相关的共聚物与聚（环氧丁烷-统计-环氧乙烷）响应嵌段，其中有较弱的链间相互作用，在没有水的情况下，被发现在几个小时内进行显着的结构转变。这项研究将探讨的假设，削弱链间相互作用的脱水状态是至关重要的，以增加组装转化率。这些研究将进一步了解这些嵌段共聚物体系及其潜在的应用。具体来说，PI和同事将研究新的亲水性-响应性-疏水性三嵌段共聚物，进一步探索可能的结构转变（例如，胶束到蠕虫状胶束），更深入地研究组装转化过程的动力学，并对嵌段共聚物组装体进行包封和释放研究。这些新的响应系统的进一步研究提供了潜在的扩展和转换的应用聚合物为基础的nanostructure.NON-TECHNICAL摘要：聚合物分子的纳米尺寸的组件显示出很大的希望在一系列的应用，从癌症和其他疾病的治疗新的传感器设备的发展。这项研究将进一步加深我们对聚合物组装体的理解，这些聚合物组装体被设计成在暴露于热或其他刺激时在尺寸和形状上发生特定变化。在这样做的过程中，它将为未来的努力奠定基础，将这些材料用于对刺激的反应可以与特定应用相结合的应用中，例如释放化疗药物或检测特定分子。这项研究将由研究生和本科生进行，作为他们科学训练的一部分，并将与斯托尼布鲁克大学、布鲁克海文国家实验室和沃里克大学（英国）的其他研究人员合作。PI将通过纽约州立大学Louis Stokes少数民族参与联盟（SUNY LSAMP）计划招募本科生参与化学系的研究。这项工作的结果将在国际参加的科学会议上提出，参与该项目的博士生将维护一个网站/博客，通过该网站/博客，他们将能够向公众传达他们对该项目和科学研究人员生活的看法。

TECHNICAL SUMMARY:Responsive polymer assemblies show great promise in a range of applications, including drug delivery, sensing, and catalysis. Crucial to the elaboration of these systems is the development of polymers that undergo rapid, predictable, and reversible changes between assemblies with different sizes and structures. For applications involving encapsulation of other species within polymer vesicles, the development of more efficient encapsulation methods is also of great importance. To meet these challenges, the PI and co-workers have previously prepared temperature-responsive ABC triblock copolymers with poly(ethylene oxide) (PEO) as a hydrophilic block, poly(N-isopropylacrylamide) as a thermoresponsive block, and polyisprene as a cross-linkable hydrophobic block, which form assemblies that undergo large changes in size and shape around a critical temperature, however the reorganization of small assemblies (micelles of 20 nm diameter) into larger assemblies (vesicles of 100 nm diameter) at elevated temperatures was found to take several weeks. Recently, related copolymers with poly(butylene oxide-stat-ethylene oxide) responsive blocks, in which there are weaker interchain interactions in the absence of water, were found to undergo significant structural transformations within several hours. This research will probe the hypothesis that weakening interchain interactions in the dehydrated state is critical to increasing assembly transformation rate. This research will further the understanding of these block copolymer systems and their potential applications. Specifically, the PI and co-workers will investigate new hydrophilic-responsive-hydrophobic triblock copolymers, further probe possible structural transformations (e.g., micelle-to-worm-like micelle), more deeply investigate the kinetics of the assembly transformation process, and carry out encapsulation and release studies with block copolymer assemblies. The further study of these novel responsive systems offers the potential to expand and transform the applications of polymer-based nanostructures.NON-TECHNICAL SUMMARY:Nanometer-sized assemblies of polymer molecules show much promise in a range of applications, from the treatment of cancer and other diseases to the development of new sensory devices. This research will further our understanding of polymer assemblies that are designed to undergo specific changes in size and shape upon exposure to heat or other stimuli. In doing so, it will lay the groundwork for future efforts to use these materials in applications where the response to stimulus can be coupled to a specific application, such as release of a chemotherapy agent or the detection of specific molecules. This research will be carried out by graduate and undergraduate students as part of their scientific training and will involve collaboration with other researchers at Stony Brook University, Brookhaven National Laboratory, and Warwick University (UK). The PI will work through the State University of New York Louis Stokes Alliance for Minority Participation (SUNY LSAMP) program to recruit undergraduate students to participate in research in the chemistry department. Results of this work will be presented at internationally-attended scientific meetings and the PhD students involved in the project will maintain a website/blog through which they will be able to communicate their reflections on the project and the life of a scientific researcher to the general public.