CAREER: Complex Phase Behavior in Block Copolymer Materials

职业：嵌段共聚物材料中的复杂相行为

• 批准号: 1844987
• 负责人: Christopher Bates
• 金额: $ 59.98万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1844987&HistoricalAwards=false
• 关键词: CAREER; Complex; Phase; Behavior; Block

NON-TECHNICAL SUMMARY:The properties of all materials depend on their structure across various length scales, from the microscopic arrangement of atoms to macroscopic shapes fashioned during processing. Nanometer-sized structures that spontaneously form ("self-assemble") in a class of materials known as "block copolymers" are widely used to create synthetic rubbers, adhesives, and next-generation computer chips among other applications. To date, there remains an incomplete understanding of what nanostructures are accessible with block copolymers, which limits new ways that they might be used. This program will uncover the fundamental molecular design rules that control structure formation in block copolymers through a combination of experiments and theory. The approach leverages synthesis to systematically manipulate polymer chemistry using concepts that are predicted to stabilize unique structures. X-ray measurements will provide insight into how self-assembly depends on composition and processing. Simulations will rationalize why certain structures are stable over others and inform refined molecular design. Fundamental knowledge uncovered in this research will promote the progress of science by elucidating the types of structure/property relationships that are central to the utility of soft materials. The outreach portion of this proposal involves broadening interest in polymer science, particularly among underrepresented demographics, via a plan targeting grade school, undergraduate, and graduate students. A series of hands-on structure/property workshops will provide 7-12th grade students with an introduction to polymer science using basic concepts from chemistry and physics. The impact of these demos will be amplified through teacher training that provides a mechanism for continual improvement and use. Curriculum development will further benefit undergraduate and graduate students who are interested in advanced topics aligned with the proposed research.TECHNICAL SUMMARY:The utility of block copolymers derives from their ability to self-assemble into well-ordered mesostructures, but the traditional phase behavior of materials with two types of block chemistries is limited to a handful of classical morphologies. Recently, a number of complex sphere packings known as Frank-Kasper phases have been discovered in simple AB diblock copolymer melts. However, to date there remains an incomplete understanding of what structures are accessible, why they develop, and how to bias their formation. This program will unravel the material design principles that govern the self-assembly of block copolymers into non-classical phases using a combination of synthesis, physical characterization, and theory. The central hypothesis underpinning this research posits that three factors known to promote interfacial curvature will influence complex phase behavior: (1) extreme conformational asymmetry in the form of statistical segment length differences between blocks, (2) the miktoarm star architecture, and (3) molecular dispersity. These topics will be investigated with a unified materials platform comprising poly(lactide) and poly(alkyl (meth)acrylate) blocks that enables systematic control over all three objectives. Small-angle X-ray scattering will be used to interrogate the structure of these materials in reciprocal space, augmented by density reconstructions and electron microscopy to probe real space. Rheological measurements will provide insight into order-disorder and order-order transitions. Self-consistent field theoretic simulations will be leveraged to rationalize these observations and guide iterative molecular design. The planned research will advance knowledge by revealing fundamental factors that control self-assembly and mesoscopic packing in soft materials.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.

非技术摘要：所有材料的特性都取决于它们在不同长度尺度上的结构，从原子的微观排列到加工过程中形成的宏观形状。在称为“嵌段共聚物”的一类材料中自发形成（“自组装”）的纳米尺寸结构被广泛用于制造合成橡胶、粘合剂和下一代计算机芯片等应用。迄今为止，人们对嵌段共聚物可实现哪些纳米结构仍不完全了解，这限制了它们的新用途。该项目将通过实验和理论的结合揭示控制嵌段共聚物结构形成的基本分子设计规则。该方法利用合成来系统地操纵聚合物化学，使用预计可稳定独特结构的概念。 X 射线测量将深入了解自组装如何依赖于成分和加工。模拟将合理解释为什么某些结构比其他结构稳定，并为精细的分子设计提供信息。这项研究发现的基础知识将通过阐明对软材料的实用性至关重要的结构/性能关系的类型来促进科学的进步。 该提案的外展部分涉及通过一项针对小学、本科生和研究生的计划，扩大对聚合物科学的兴趣，特别是在代表性不足的人群中。一系列结构/性质实践研讨会将为 7-12 年级的学生提供使用化学和物理基本概念的高分子科学介绍。这些演示的影响将通过教师培训得到放大，提供持续改进和使用的机制。课程开发将进一步使对与拟议研究相关的高级主题感兴趣的本科生和研究生受益。技术摘要：嵌段共聚物的实用性源于其自组装成有序介观结构的能力，但具有两种嵌段化学性质的材料的传统相行为仅限于少数经典形态。最近，在简单的 AB 二嵌段共聚物熔体中发现了许多被称为 Frank-Kasper 相的复杂球体堆积。 然而，迄今为止，对于哪些结构是可访问的、它们为何发展以及如何偏向它们的形成，仍然存在不完全的理解。该项目将结合合成、物理表征和理论，揭示控制嵌段共聚物自组装成非经典相的材料设计原理。支持这项研究的中心假设认为，已知促进界面曲率的三个因素将影响复杂的相行为：（1）以块之间统计段长度差异的形式出现的极端构象不对称性，（2）miktoarm星形结构，以及（3）分子分散性。这些主题将通过包含聚丙交酯和聚（甲基）丙烯酸烷基酯）嵌段的统一材料平台进行研究，该平台能够系统地控制所有三个目标。小角度 X 射线散射将用于询问这些材料在倒易空间中的结构，并通过密度重建和电子显微镜来增强以探测真实空间。流变测量将提供对有序-无序和有序-有序转变的深入了解。将利用自洽场论模拟来合理化这些观察结果并指导迭代分子设计。计划中的研究将通过揭示控制软材料中自组装和介观堆积的基本因素来增进知识。该奖项反映了 NSF 的法定使命，并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，被认为值得支持。

项目成果

Efficient Creation and Morphological Analysis of ABC Triblock Terpolymer Libraries

• DOI: 10.1021/acs.macromol.2c01480
• 发表时间: 2022-10
• 期刊: Macromolecules
• 影响因子: 5.5
• 作者: Elizabeth A. Murphy;Yan-Qiao Chen;Kaitlin R. Albanese;Jacob R. Blankenship;Allison Abdilla;M. Bates;Cheng Zhang;Christopher M. Bates;C. Hawker

Flow-Induced Concentration Nonuniformity and Shear Banding in Entangled Polymer Solutions

• DOI: 10.1103/physrevlett.126.207801
• 发表时间: 2021-05-20
• 期刊: PHYSICAL REVIEW LETTERS
• 影响因子: 8.6
• 作者: Burroughs, Michael C.;Zhang, Yuanyi;Helgeson, Matthew E.
• 通讯作者: Helgeson, Matthew E.

Simulation-guided analysis of resonant soft X-ray scattering for determining the microstructure of triblock copolymers

用于确定三嵌段共聚物微观结构的共振软 X 射线散射模拟引导分析

• DOI: 10.1039/d2me00096b
• 发表时间: 2022
• 期刊: Molecular Systems Design & Engineering
• 影响因子: 3.6
• 作者: Reynolds, Veronica G.;Callan, Devon H.;Saurabh, Kumar;Murphy, Elizabeth A.;Albanese, Kaitlin R.;Chen, Yan-Qiao;Wu, Claire;Gann, Eliot;Hawker, Craig J.;Ganapathysubramanian, Baskar
• 通讯作者: Ganapathysubramanian, Baskar