Shape Changing Stimuli-Responsive Multicomponent Molecular Bottlebrushes in Solution and at Interfaces

溶液中和界面处的形状变化刺激响应多组分分子洗瓶刷

• 批准号: 2004564
• 负责人: Bin Zhao
• 金额: $ 55万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2004564&HistoricalAwards=false
• 关键词: Shape; Changing; Stimuli; Responsive; Multicomponent

PART 1: NON-TECHNICAL SUMMARYMolecular bottlebrush polymers are a class of chain-like molecules composed of a very long polymer backbone with densely grafted shorter molecules. These polymers exhibit intriguing properties and could be used, e.g., in manufacture of advanced materials, lubrication for friction reduction, drug delivery for medication. Their shapes are governed by the length ratio of backbone and side chains and the interactions of side chains with themselves and their environment. External stimuli have been shown to trigger the shape change of brush polymers from wormlike to globular, which mimics the folding and unfolding behavior of natural proteins. In this project the PI will design, prepare, and study multicomponent brush polymers that can individually change their shapes in solutions and at interfaces upon application of external stimuli. The fundamental understanding of the properties and behavior of such giant molecules under various conditions will potentially impact many technologies, including targeted delivery of substances (e.g., medications) and environmentally responsive foams and emulsions. The research program will provide a platform for training postdoctoral researchers, graduate and undergraduate students, and thus will have broader societal impact beyond the research itself. Outreach activities will be directed to stimulate the interest of high school students toward STEM fields and to broaden the science horizons of the students at the University of Tennessee Knoxville.PART 2: TECHNICAL SUMMARYThis project is aimed at synthesizing multicomponent molecular bottlebrush polymers that can display shape changes in response to external stimuli and understanding how various molecular parameters affect their shape changing behavior in dilute and moderately concentrated solutions and at interfaces. Specifically, the research program will utilize previously developed synthetic strategies to prepare stimuli-responsive multicomponent brush polymers via state-of-the-art synthesis techniques, characterize their changes in molecular dimension and conformation (shape) upon application of external stimuli in dilute and moderately concentrated aqueous solution, under external fields, and at interfaces, elucidate the effects of various molecular parameters on shape-changing behavior, and reveal the unique properties of brush polymers under different conditions. A series of multicomponent molecular bottlebrush polymers with various chemical compositions, molecular weights, molecular architectures, and narrow dispersities will be made. They will be investigated by multidetector size exclusion chromatography (SEC) for molecular weights and dimensions, dynamic and static light scattering (DLS and SLS) for molecular sizes under different conditions, atomic force microscopy (AFM) and transmission electron microscopy (TEM) for direct visualization on substrates, and small angle neutron scattering (SANS) for in situ study of brush dimensions and conformations in solutions. The knowledge gained from this research project will be used to guide the design and synthesis of functional brush polymers for potential applications in delivery of substances and stimuli-responsive foams and emulsions.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.

第 1 部分：非技术概要分子洗瓶刷聚合物是一类链状分子，由非常长的聚合物主链和密集接枝的较短分子组成。这些聚合物表现出有趣的特性，可用于先进材料的制造、减少摩擦的润滑、药物的药物输送等。它们的形状取决于主链和侧链的长度比以及侧链与其自身及其环境的相互作用。外部刺激已被证明可以触发刷状聚合物的形状变化，从蠕虫状变为球状，从而模仿天然蛋白质的折叠和展开行为。在这个项目中，PI 将设计、制备和研究多组分刷状聚合物，这些聚合物可以在施加外部刺激时单独改变其在溶液中和界面处的形状。对此类大分子在各种条件下的性质和行为的基本了解将潜在地影响许多技术，包括物质（例如药物）的定向输送以及环境响应型泡沫和乳液。该研究项目将为培养博士后研究人员、研究生和本科生提供平台，因此将产生超出研究本身的更广泛的社会影响。外展活动将旨在激发高中生对 STEM 领域的兴趣，并拓宽田纳西大学诺克斯维尔分校学生的科学视野。第 2 部分：技术摘要该项目旨在合成可显示形状的多组分分子洗瓶刷聚合物响应外部刺激而发生变化，并了解各种分子参数如何影响其在稀溶液和中等浓度溶液以及界面处的形状变化行为。具体来说，该研究计划将利用先前开发的合成策略，通过最先进的合成技术制备刺激响应性多组分刷状聚合物，表征在稀释和适度的外部刺激下其分子尺寸和构象（形状）的变化。浓水溶液在外场下和界面处，阐明了各种分子参数对形状变化行为的影响，并揭示了刷状聚合物在不同条件下的独特性能。将制造一系列具有不同化学成分、分子量、分子结构和窄分散性的多组分分子瓶刷聚合物。将通过多检测器尺寸排阻色谱 (SEC) 来研究它们的分子量和尺寸，动态和静态光散射（DLS 和 SLS）来研究不同条件下的分子大小，原子力显微镜 (AFM) 和透射电子显微镜 (TEM) 来直接研究它们。基板上的可视化和小角度中子散射（SANS）用于原位研究溶液中的刷子尺寸和构象。从该研究项目中获得的知识将用于指导功能性刷状聚合物的设计和合成，以用于物质输送以及刺激响应泡沫和乳液方面的潜在应用。该奖项反映了 NSF 的法定使命，并通过评估被认为值得支持利用基金会的智力优势和更广泛的影响审查标准。

项目成果

pH- and chaotropic anion-induced conformational changes of tertiary amine-containing binary heterografted star molecular bottlebrushes in aqueous solution

pH 和离液阴离子诱导水溶液中含叔胺二元异质接枝星形分子瓶刷的构象变化

• DOI: 10.1039/d0py01466d
• 发表时间: 2021-01
• 期刊: Polymer Chemistry
• 影响因子: 4.6
• 作者: Kent, Ethan W.;Lewoczko, Evan M.;Zhao, Bin
• 通讯作者: Zhao, Bin

Effects of N -Substituents on the Solution Behavior of Poly(sulfobetaine methacrylate)s in Water: Upper and Lower Critical Solution Temperature Transitions

N-取代基对聚磺基甜菜碱甲基丙烯酸酯在水中溶液行为的影响：上下临界溶液温度转变

• DOI: 10.1021/acsapm.0c01191
• 发表时间: 2021-02
• 期刊: ACS Applied Polymer Materials
• 影响因子: 5
• 作者: Lewoczko, Evan M.;Wang, Ning;Lundberg, Claire E.;Kelly, Michael T.;Kent, Ethan W.;Wu, Tao;Chen, Ming;Wang, Jian;Zhao, Bin
• 通讯作者: Zhao, Bin

Effects of temperature on chaotropic anion-induced shape transitions of star molecular bottlebrushes with heterografted poly(ethylene oxide) and poly( N , N -dialkylaminoethyl methacrylate) side chains in acidic water

酸性水中温度对异质接枝聚环氧乙烷和聚(N,N-二烷基氨基乙基甲基丙烯酸酯)星型分子瓶刷形状转变的影响

• DOI: 10.1039/d1sm00728a
• 发表时间: 2021-07
• 期刊: Soft Matter
• 影响因子: 3.4
• 作者: Lewoczko, Evan M.;Kelly, Michael T.;Kent, Ethan W.;Zhao, Bin
• 通讯作者: Zhao, Bin

Shape-Changing Bottlebrush Polymers

变形洗瓶刷聚合物

• DOI: 10.1021/acs.jpcb.1c01819
• 发表时间: 2021-05
• 期刊: The Journal of Physical Chemistry B
• 作者: Zhao; Bin
• 通讯作者: Bin