Random-Blocky Copolymers: Monomer Sequencing through Templated Chemical Coloring

提出的研究计划的中心主题是证明随机块状共聚物（rbc）的能力，具有统计控制的单体序列分布的杂多聚合物，进行批量自组装并在表面上执行化学模式识别。我们计划建立控制单体测序的统计性质足以赋予红细胞独特的组装和识别特征；这些可能允许红细胞执行类似于那些更复杂的生物分子的功能。红细胞将通过调整溶液中均聚物的旋转半径来合成，然后对那些“着色”部分在空间上可接近的单体进行化学修饰（“着色”）。根据均聚物的崩解程度（不良溶剂）或膨胀程度（良好溶剂），红细胞中的单体序列分布从块状（不良溶剂）到随机（良好溶剂）不等。我们提出了基于聚（苯乙烯-co-4-溴苯乙烯）和聚（二甲基氨基乙基甲基丙烯酸酯-共烷基）的红细胞合成方案。我们表明，聚（苯乙烯-co-4溴苯乙烯）红细胞可以通过附加其他化学功能进一步进行化学定制。一组分析探针，包括核磁共振、元素分析和克尔效应测量，将被用于建立红细胞的化学组成和单体序列分布。分析方法将与使用蒙特卡罗模拟的建模研究相辅相成，这将揭示关于“着色”过程本质的分子水平的见解。我们还提出了一种在小硅球表面制备红细胞的新方法。提出了一套全面的实验，旨在了解红细胞在溶液中的组装和红细胞在溶液/固体和熔体/固体界面上的吸附。后一种方法的主要重点是研究共聚物序列分布、聚合物/固体相互作用和底物的化学非均质性之间的相互作用。高空间分辨率深度剖面技术，包括中子和x射线反射率、光谱椭偏和离子束技术；将与选择性氘标记一起应用，以探测固体/液体和固体/熔体界面上红细胞的体积分数分布和面内分布。所提议活动的知识价值：这项工作的主要成果将是证明红细胞，尽管具有统计性质，能够执行与精确控制单体序列分布的大分子类似的功能。我们将证明，简单的化学着色方法可以用来生产具有广泛的化学和功能的红细胞。合成、实验和建模的结合将为研究红细胞的溶液组装和界面活性提供非常强大的工具。拟议活动产生的更广泛影响：红细胞可被视为“蛋白质前体”的最简单模拟物。研究它们的溶液自组装和界面性质有望揭示非常复杂的生物分子行为的重要见解。拟议项目的技术前景包括，但远远超出了基于生物材料的健康应用。了解这种大分子的界面性能为设计新材料和结构提供了前所未有的手段，这些材料和结构可以广泛应用于各种软凝聚物质应用，包括纳米反应器，组织非聚合纳米内含物的“种子”。我们还概述了我们在培养研究生方面的努力，概述了在北卡罗来纳州Mount Airy的一所小学的外展活动，并希望吸引当地K-12学生参加我们的跨学科研究努力。

The central theme of the proposed research plan is to demonstrate the ability of random-blocky copolymers (RBCs), heteropolymers with statistically controlled monomer sequence distributions, to undergo self-assembly in the bulk and perform recognition of chemical patterns on surfaces. We plan to establish that controlling the statistical nature of the monomer sequencing is sufficient in endowing the RBC with unique assembling and recognition characteristics; these may allow the RBCs to perform functions similar to those of more complex biomolecules. The RBCs will be synthesized by adjusting the radius of gyration of a homopolymer in solution, followed by chemical modification ("coloring") of those monomers that are sterically accessible to the "coloring" moiety. Depending on the degree of collapse (poor solvent) or expansion (good solvent) of the homopolyer, the monomer sequence distribution in the RBC will range from blocky (poor solvent) to random (good solvent). We propose synthetic schemes leading to RBCs based on poly (styrene-co-4-bromostyrene) and poly(dimethyl aminoethyl methacrylate-co-alkyl). We show that poly(styrene-co-4bromostyrene) RBCs can be further chemically tailored by attaching other chemical functionalties. A set of analytical probes, including NMR, elemental analysis, and Kerr effect measurements, will be applied to establish the chemical composition and monomer sequence distribution in the RBCs. The analytical methods will be complemented with modeling studies using Monte Carlo simulations, which will reveal molecular-level insight about the nature of the "coloring" procedure. We also propose a new method for preparing RBCs on the surfaces of small silica spheres. A comprehensive set of experiments is proposed that aim at understanding the assembly of RBCs in solution and the adsorption of RBCs at solution/solid and melt/solid interfaces. The main focus of the latter methods is to investigate the interplay between the copolymer sequence distributioin, the polymer/solid interactions, and chemical heterogeneities of the substrate. High spatial resolution depth profiling techniques, including neutron and X-ray reflectivity, spectroscopic ellipsometry, and ion beam techniques, will be applied in conjunction with selective deuterium labeling to probe the volume fraction profiles and the in-plane distributioin of the RBCs at solid/liquid and solid/melt interfaces. Intecllectual merit of the proposed activity: The major outcome of this work will be the demonstration that RBCs, in spite of their statistical nature, are capable of performing functions similiar to those of macromolecules with precisely controlled monomer sequence distributions. We will demonstrate that simple chemical coloring methods can be employed in order to produce RBCs with a wide range of chemistries and functionalites. The combination of the synthesis, experiment, and modeling will offer very powerful tools for studying the solution assembly and interfacial activity of RBCs. Broader impact resulting from the proposed activity: The RBCs may be considered the simplest mimics of "protein precursors". Studying their solution self-assembly and interfacial properties is expected to reveal important insight into the behavior of very complex biomolecules. The technological promise of the proposed project includes, but extends well beyond, the health of biomaterial-based applications. Understanding the interfacial performance of such macromolecules provides unprecedented means of designing novel materials and stuctures that can find widespread, use in a variety of soft-condensed matter applications, including nano-reactors, "seeds" for organizing non-polymeric nano-inclusions. We also outline our efforts in training graduate students, outline outreach activities in an elementary school in Mount Airy, NC, and popose to attract local K-12 students to take part in our interdisciplinary research endeavor.