Polymer Crystallization at Curved Liquid/Liquid Interface

弯曲液/液界面处的聚合物结晶

• 批准号: 1308958
• 负责人: Christopher Li
• 金额: $ 48.8万
• 依托单位: Drexel University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1308958&HistoricalAwards=false
• 关键词: Polymer; Crystallization; Curved; Liquid; Interface

TECHNICAL SUMMARY: Curved space is incommensurate with typical ordered structures with three-dimensional (3D) translational symmetry. However, upon assembly, soft matter, including colloids, amphiphiles, and block copolymers (BCPs), often forms structures depicting curved surface/interface. Examples include liposomes, colloidosomes, spherical micelles, worm-like micelles, and vesicles (also known as polymersomes). For crystalline BCPs, crystallization oftentimes overwrites curved geometries since the latter is incommensurate with crystalline order. On the other hand, twisted and curved crystals are often observed in crystalline polymers. Various mechanisms have been proposed for these non-flat crystalline morphologies. One intriguing question would be: how do curved space and crystalline order co-exist in polymeric systems? In this work, the PI proposes to systematically investigate polymer solution crystallization at curved L/L interface using an emulsion-solution crystallization method. The objectives of the project are: 1) understanding the polymer single crystal growth mechanism at curved L/L interface; 2) understanding structure and mechanical properties of curved polymer single crystals; and 3) fabricating multicomponent shell ensembles using polymer single crystals. From a scientific standpoint, packing crystalline chains in a curved incommensurate space is an intriguing question to study. From a technological standpoint, if successful, the well-controlled single- or multiple-component ensembles will not only shed light on using polymeric capsules for drug delivery and gene therapeutics, they can also be extremely useful for applications such as catalysis, surface enhanced Raman spectroscopy, and artificial nanomotors.NON-TECHNICAL SUMMARY: Twisted and curved crystals are often observed in crystalline large molecules such as polymers. This is intriguing because by definition, crystals should lead to flat instead of curved surfaces. In this work, the PI proposes to investigate polymer crystallization at curved space and more importantly, to guide polymers to form tiny crystal shells whose radii are about one thousandth the diameter of a human hair! The tiny shells can be used as capsules to deliver drugs to specific locations needed to cure diseases. From a technological standpoint, the proposed research, if successful, will pave the way to improving the performance of polymeric capsules for drug delivery because these capsules are more stable than many other systems that are currently used. The educational component of the proposal includes: 1) addressing the need for the education of modern developments in polymer nanoscience and nanotechnology by developing two class modules which will be used in the Nanostructured Polymeric Materials course. 2) Involving graduate, undergraduate, high school students and teachers, particularly under-represented populations, in the proposed research activities.

技术概述：弯曲空间与典型的三维（3D）平移对称有序结构不相称。然而，在组装后，软物质，包括胶体、两亲体和嵌段共聚物（bcp），通常形成描绘曲面/界面的结构。例子包括脂质体、胶体体、球形胶束、蠕虫状胶束和囊泡（也称为聚合体）。对于结晶bcp，结晶通常覆盖弯曲的几何形状，因为后者与结晶顺序不相称。另一方面，在结晶性聚合物中经常观察到扭曲和弯曲的晶体。对于这些非扁平晶体形态，人们提出了各种不同的机制。一个有趣的问题是：弯曲空间和结晶秩序是如何在聚合物体系中共存的？在这项工作中，PI提出系统地研究聚合物溶液在弯曲L/L界面上的结晶，使用乳液-溶液结晶方法。本课题的目标是：1)了解聚合物单晶在弯曲L/L界面上的生长机理；2)了解弯曲聚合物单晶的结构和力学性能；3)利用聚合物单晶制备多组分壳系。从科学的角度来看，在弯曲的不相称空间中排列晶体链是一个有趣的研究问题。从技术的角度来看，如果成功的话，这种控制良好的单组分或多组分集成不仅将阐明聚合物胶囊用于药物输送和基因治疗，而且在催化、表面增强拉曼光谱和人工纳米马达等应用中也非常有用。非技术总结：在结晶大分子如聚合物中经常观察到扭曲和弯曲的晶体。这很有趣，因为根据定义，晶体应该导致平面而不是曲面。在这项工作中，PI建议研究弯曲空间中的聚合物结晶，更重要的是，引导聚合物形成半径约为人类头发直径千分之一的微小晶体壳！这种微小的外壳可以用作胶囊，将药物输送到治疗疾病所需的特定部位。从技术的角度来看，这项研究如果成功，将为提高聚合物胶囊的药物输送性能铺平道路，因为这些胶囊比目前使用的许多其他系统更稳定。该提案的教育部分包括：1)通过开发将用于纳米结构聚合物材料课程的两个课程模块，解决聚合物纳米科学和纳米技术现代发展教育的需求。2)让研究生、本科生、高中生和教师，特别是代表性不足的人群参与拟议的研究活动。