CAS: Sequence in Brush Copolymers

在化学系大分子、超分子和纳米化学项目的支持下，匹兹堡大学的Tara Y. Meyer教授正在制备具有二维序列控制的新型刷状共聚物材料，并研究了主链和侧链序列对水解降解谱的综合影响。聚合物刷是一种大分子，其中主聚合物链接枝有不同密度的附加聚合物链。它们具有有用的性质，包括蠕虫状构象，紧凑的分子尺寸，以及由于其紧凑和受限的结构而显着的聚合物链端效应。因此，这种刷子在生物医学设备、化学传感器、药物输送系统和组织工程中是很有前途的聚合物。在本研究中，化学反应将首先用于制备具有可生物降解和生物相容性侧链的聚合物刷，侧链由不同序列的乳酸和乙醇酸组成。制备的刷子将用于降解研究，目的是研究不同的刷子结构和侧链的二维序列对降解率的影响。与这项研究相关的活动旨在扩大参与，并使本科生和研究生在聚合物化学、有机合成和催化方面得到培训。与由六所机构组成的第1章NOBCChE合作组织的互动，包括三所历史上的黑人学院和大学（HBCUs），将继续专注于培养成员之间的长期关系，目标是共同努力，支持化学领域代表性不足群体的学生的成功和保留。本研究将集中于控制含有可生物降解和生物相容性的“α -羟基酸衍生”侧链的刷状共聚物的序列。在第一个目标中，将利用钌催化开环复分解聚合制备一二维序列控制的降冰片烯基刷。通过对乳酸和乙醇酸侧链优化的方法接枝将被利用。第二个目标将侧重于循环刷状共聚物的合成和表征，包括可以使用熵驱动聚合开环的变体，以创建交替刷状线性多嵌段共聚物。最后，将研究序列和结构对水解降解率的综合影响，目的是建立对序列刷状共聚物降解的机制理解。了解聚合物结构与降解之间相互作用的基础研究有可能导致改进基于刷的药物输送载体的设计。此外，与本研究相关的刷线状多嵌段共聚物的合成和表征可能会影响需要具有类组织特性的聚合物的应用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Macromolecular, Supramolecular and Nanochemistry program in the Division of Chemistry, Professor Tara Y. Meyer of the University of Pittsburgh is preparing novel brush copolymer materials with 2-dimensional sequence control and studying the combined effects of both backbone and sidechain sequence on the hydrolytic degradation profiles. Polymer brushes are type of macromolecules in which the main polymer chain is grafted with additional polymer chains of varying density. They have useful properties including wormlike conformations, compact molecular dimensions, and notable polymer chain-end effects due to their compact and confined structures. As such, the brushes are promising polymers for biomedical devices, chemical sensors, drug-delivery systems, and tissue engineering. In this research, chemical reactions will first be used to prepare polymer brushes with biodegradable and biocompatible side chains consisting of different sequences of lactic and glycolic acids. The prepared brushes will then be utilized in degradation studies with the aim to investigate the effects of different brush architectures and 2-dimensional sequences of side chains on the degradation rate. The activities associated with this research are designed to broaden participation and enable training of undergraduate and graduate students in polymer chemistry, organic synthesis, and catalysis. The interactions with a Charter 1 NOBCChE collaborative consisting of six institutions, including three historically black colleges & universities (HBCUs), will continue to focus on fostering long-term relationships among members with the goal of working together to support the success and retention of students from underrepresented groups in chemistry.This research will focus on controlling sequences in brush copolymers containing biodegradable and biocompatible "alpha-hydroxy acid derived" sidechains. In the first objective, one- and two-dimensional sequence controlled norbornene based brushes will be prepared using ruthenium catalyzed ring-opening metathesis polymerization. Grafting through methodology optimized for lactic and glycolic acids side chains will be utlized. The second objective will focus on the synthesis and characterization of cyclic brush copolymers with two-dimensional sequence control including variants that can be ring-opened using an entropy-driven polymerization to create alternating brush-linear multiblock copolymers. Lastly, the combined effects of sequence and architecture on hydrolytic degradation rates, with the goal of developing a mechanistic understanding of the degradation in sequenced brush copolymers, will be investigated. Fundamental studies related to understanding of the interactions between polymer architecture and degradation have the potential to lead to improved design of brush-based drug delivery vehicles. Additionally, the synthesis and characterization of the brush-linear multiblock copolymers associated with this research could impact applications that require polymers with tissue-like properties.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.