CAREER: Visualizing single-chain conformation and dynamics of bottlebrush polymers in the bulk state

职业：可视化散装状态下的瓶刷聚合物的单链构象和动力学

• 批准号: 1945249
• 负责人: Muzhou Wang
• 金额: $ 60万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1945249&HistoricalAwards=false
• 关键词: CAREER; Visualizing; single; chain; conformation

NON-TECHNICAL SUMMARYPolymers are used everywhere in our daily lives in almost every application imaginable. After decades of research, it is still nearly impossible to directly see the shape of a single polymer molecule and how it moves in its native environment, because the typical sizes of polymer chains are too small. This project uses the next generation of optical techniques called super-resolution microscopy to achieve this goal of directly imaging how single polymers behave in the solid state. While these techniques have been explored in several biological applications for achieving tens of nanometer resolutions, their use in materials science has been much more limited. This work will focus on a specific class of polymers called bottlebrushes, which have attracted interest for photonic materials and drug delivery, and happen to be a perfect size to be imaged by super-resolution. This project will directly address the question of how the structure and behavior of single polymers connect to the properties of the material at everyday length scales. Beyond the fundamental understanding that this offers, it will also enable efficient design of new materials for societal benefit. In addition, the further application of super-resolution microscopy to materials science will make it easier for others in this community to adopt these methods to their own research problems. In line with this theme of nanotechnology and materials science, this project will also support new curriculum development for Junior Science Club, an afterschool activity for underrepresented youths of grades 3-5. Graduate students and volunteers across campus will mentor students weekly over new 6-8 week modules, which will be publicly available and ready for adoption by others offering similar programs. TECHNICAL SUMMARYThe connection between single-chain behavior and macroscopic properties is a central tenet in our modern understanding of polymer physics. However, direct visualization of single polymers is difficult particularly in application-relevant configurations, because single polymer chains are typically nanometers in size. This project tackles the grand challenge of imaging the conformation and dynamics of single polymer chains within a bulk material. The experiments will utilize super-resolution microscopy, which can image structures at tens of nanometer resolution, both non-invasively and with chemical specificity through fluorescent labeling. The specific polymers in this study are bottlebrushes, exploring the conformational rigidity in the bulk vs. previous dilute solution results, and directly visualizing entanglement dynamics. The questions posed here can be directly answered by visualization of single chains, while other techniques such as scattering, rheology, and simulation can only probe these questions indirectly.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.

非技术概述聚合物在我们的日常生活中几乎在每一个可以想象的应用中无处不在。经过几十年的研究，仍然几乎不可能直接看到单个聚合物分子的形状以及它在其天然环境中的运动方式，因为聚合物链的典型尺寸太小。该项目使用称为超分辨率显微镜的下一代光学技术来实现直接成像单个聚合物在固态下的行为的目标。虽然这些技术已经在几个生物应用中进行了探索，以实现数十纳米的分辨率，但它们在材料科学中的应用却受到了更多的限制。这项工作将集中在一种称为瓶刷的特定类型的聚合物上，这种聚合物已经引起了人们对光子材料和药物输送的兴趣，并且恰好是通过超分辨率成像的完美尺寸。该项目将直接解决单一聚合物的结构和行为如何与日常长度尺度下的材料特性相关联的问题。除了提供基本的理解之外，它还将使新材料的有效设计能够造福社会。此外，超分辨率显微镜在材料科学中的进一步应用将使该社区的其他人更容易采用这些方法来解决自己的研究问题。根据纳米技术和材料科学这一主题，该项目还将支持青少年科学俱乐部的新课程开发，这是一项针对3-5年级代表性不足的青少年的课外活动。 整个校园的研究生和志愿者将在新的6-8周模块中每周指导学生，这些模块将公开提供，并准备由其他提供类似课程的人采用。单链行为和宏观性质之间的联系是我们现代理解聚合物物理学的中心原则。然而，单个聚合物的直接可视化是困难的，特别是在与应用相关的配置中，因为单个聚合物链的尺寸通常为纳米。这个项目解决了成像的构象和动态的单个聚合物链在散装材料的巨大挑战。这些实验将利用超分辨率显微镜，它可以以数十纳米的分辨率对结构进行成像，既可以是非侵入性的，也可以通过荧光标记进行化学特异性。本研究中的特定聚合物是瓶刷，探索本体与之前稀释溶液结果的构象刚性，并直接可视化缠结动力学。这里提出的问题可以直接通过单链的可视化来回答，而其他技术，如散射，流变学和模拟只能间接地探索这些问题。这个奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

项目成果

Direct visualization of bottlebrush polymer conformations in the solid state

• DOI: 10.1073/pnas.2109534118
• 发表时间: 2021-10-05
• 期刊: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• 影响因子: 11.1
• 作者: Chan, Jonathan M.;Kordon, Avram C.;Wang, Muzhou
• 通讯作者: Wang, Muzhou