Effect of Chain-ends on the Mixed Polymer Brush Morphology

链端对混合聚合物刷形态的影响

• 批准号: 2003891
• 负责人: Padma Gopalan
• 金额: $ 45万
• 依托单位: University of Wisconsin-Madison
• 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=2003891&HistoricalAwards=false
• 关键词: Effect; Chain; ends; Mixed; Polymer

PART 1: NON-TECHNICAL SUMMARYPolymer brushes are long stringy molecules that are chemically anchored to a surface to form a dense, thin coating that alters the surface properties. While the chemical anchoring to the surface provides the required mechanical strength to the coating, the chemistry and structure of the polymer enables communication with the environment. Hence, these coatings have broad relevance in solving problems in materials science and in human health. They can act as sensors for rapid detection of biomarkers in biofluids when anchored to electronically active surfaces, direct cell growth for regenerative medicine, resist deposition of micro-organisms on surfaces, control flow of charge in batteries, control friction at relevant interfaces., etc. This research program will develop new synthetic methodologies to make these polymer brushes with well defined structure and chemistry. The methodology developed is high yielding, simple and reproducible on a wide range of surfaces, hence can be adapted by the coating industry. This program will develop characterization methods to aid in the molecular level understanding of the resulting structure. The research program will serve to inspire and involve undergraduate students in polymer science and engineering research, by working with graduate student mentors, through the REU program. Educational modules will also be developed for dissemination through UW-Madison’s institute for Chemical Education, a national center dedicated to STEM education through outreach and education research. PART 2: TECHNICAL SUMMARYThe research program will develop a highly versatile approach to grow mixed A/B polymer brushes from a substrate using a cross-linkable copolymer coating, which contains a polymerizable initiator (inimer) as a comonomer. Mixed A/B polymer brushes consist of chemically distinct A and B chains, randomly grafted to the surface. They show changing density, height and composition profile as a function of solvent environment. These polymer brushes will have high chain grafting density, uniform distribution of A and B graft points, controlled molecular weights, and excellent control over composition. Theory predicts the lowering of critical point for phase separation in mixed brushes compared to block copolymers, and the formation of nanoscale morphology. However, experimental studies have fallen short of validating these predictions. The gap between theory and experiments is attributable to lack of: a) experimental methods for uniform growth of high grafting density mixed brushes with controllable grafting ratios, and predictable chain lengths, (b) accounting for chain end-groups in theory and experiments, and (c) characterization methods to study the morphology. In this project the goal is to understand the role of chain-end density, size, distribution, and type on the A/B mixed brush morphology. This is a largely experimentally and theoretically unexplored area in polymer brushes. Key aspects of this research will be to develop synthetic strategies to append select chain end groups, quantification of the extent of functionalization and chain-end distribution by a combination of X-ray photoelectron spectroscopy and Resonant Soft X-ray scattering (RSoXS), and studying the effect of chain-end functionalization on lateral phase segregation by a combination of scattering and advanced microscopy techniques. The morphological insight developed through these experiments will contribute towards the broader understanding and application of polymer brushes..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：非技术摘要聚合物刷是长长的分子，在化学上固定在表面上，形成一个密集的薄涂层，以改变表面性质。尽管化学锚定在表面上为涂层提供了所需的机械强度，但聚合物的化学和结构可以与环境进行通信。因此，这些涂料在解决材料科学和人类健康方面的问题方面具有广泛的意义。当锚定在电子活跃的表面上，直接细胞生长，再生药物的直接细胞生长，在电池表面上的控制，电池的控制，相关界面的控制摩擦在相关界面上的控制流程等，它们将充当生物流体中生物流体生物标志物快速检测的传感器。该研究程序将开发出新的合成方法，并构成这些综合方法。开发的方法是高产，简单且可在各种表面上可重现的，因此可以由涂料行业进行调整。该程序将开发出表征方法，以帮助分子水平理解所得结构。该研究计划将通过REU计划与研究生导师合作，从而激发并参与聚合物科学和工程研究的本科生。教育模块还将通过UW-Madison化学教育研究所开发用于传播，这是一个国家中心，致力于通过外展和教育研究来茎教育。第2部分：技术总结研究计划将使用可使用可连接的共聚物涂层从底物中从底物中生长出高度的方法，该方法包含一个可聚合的引发剂（INIMER）作为一个社区。混合的A/B聚合物刷由化学上不同的A和B链组成，随机移植到表面上。它们显示了随着偿付能力环境的函数而变化的密度，高度和组成曲线。这些聚合物刷将具有高链移植密度，A和B移植点的均匀分布，受控的分子量以及对组成的良好控制。理论预测与块共聚物相比，混合刷中相位分离的临界点降低，以及纳米级形态的形成。但是，实验研究未能验证这些预测。理论和实验之间的差距归因于：a）具有控制嫁接比的高移植密度混合刷均匀生长的实验方法，以及可预测的链长，（b）考虑理论和实验中链端组的链条，以及（c）研究形态学的表征方法。在这个项目中，目标是了解A/B混合刷形态上链端密度，大小，分布和类型的作用。这是聚合物刷中的实验和理论意外区域。这项研究的关键方面将是开发合成策略，以补充链条终端组，功能化程度和链末端分布的数量，结合X射线光电镜头和谐振软X射线散射（RSOXS）的组合，以及研究链 - 末端函数对以后相位隔离的效应，并通过散射技术组合的链接功能。通过这些实验开发的形态学洞察力将有助于更广泛的理解和应用聚合物刷子。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响来评估，被认为是宝贵的支持。

项目成果

Formamide based monomer for highly functionalized polymers

• DOI: 10.1002/pol.20210651
• 发表时间: 2021-11
• 期刊: Journal of Polymer Science
• 影响因子: 3.4
• 作者: Ri Chen;Balamurugan Ayyakkalai;Jian Sun;Gene Lee;P. Gopalan

Photoimageable Organic Coating Bearing Cyclic Dithiocarbonate for a Multifunctional Surface

• DOI: 10.1021/acsami.1c19559
• 发表时间: 2022-01-04
• 期刊: ACS APPLIED MATERIALS & INTERFACES
• 影响因子: 9.5
• 作者: An，Sol;Nam，Jieun;Kim，Myungwoong
• 通讯作者: Kim，Myungwoong

Chain End-Functionalized Dense Polymer Brushes from an Inimer Coating by SI-RAFT

• DOI: 10.1021/acs.langmuir.3c00733
• 发表时间: 2023-05-30
• 期刊: LANGMUIR
• 影响因子: 3.9
• 作者: Smith，Julia D.;Salas，Luis Adrian Padilla;Gopalan，Padma
• 通讯作者: Gopalan，Padma

Synthesis of High Etch Contrast Poly(3-hydroxystyrene)-Based Triblock Copolymers and Self-Assembly of Sub-5 nm Features

• DOI: 10.1021/acs.macromol.1c01611
• 发表时间: 2021-10
• 期刊: Macromolecules
• 影响因子: 5.5
• 作者: Jian Sun;Changyeon Lee;C. Osuji;P. Gopalan

Selectively Grown Quantum Dot Active Region Lasers

选择性生长的量子点有源区域激光器

• DOI: 10.1109/jqe.2022.3145838
• 发表时间: 2022
• 期刊: IEEE journal of quantum electronics
• 影响因子: 2.5
• 作者: Mawst, L. J.;Kim, H.;Wei, W.;Talreja, D.;Kuech, T. F.;Gopalan, P.
• 通讯作者: Gopalan, P.