Random-Blocky Copolymers: Monomer Sequencing through Templated Chemical Coloring

拟议的研究计划的中心主题是证明随机嵌段共聚物（RBC）的能力，具有统计控制的单体序列分布的杂聚物，在本体中进行自组装，并在表面上进行化学图案的识别。 我们计划确定控制单体测序的统计性质足以赋予RBC独特的组装和识别特征;这些可能使RBC执行类似于更复杂的生物分子的功能。 RBC将通过调节溶液中均聚物的回转半径，然后对“着色”部分在空间上可接近的那些单体进行化学修饰（“着色”）来合成。 取决于均聚物的塌陷（不良溶剂）或膨胀（良好溶剂）的程度，RBC中的单体序列分布将在从嵌段（不良溶剂）到无规（良好溶剂）的范围内。 我们提出了基于聚（苯乙烯-co-4-溴苯乙烯）和聚（甲基丙烯酸二甲基氨基乙酯-co-烷基）的红细胞合成方案。 我们表明，聚（苯乙烯-co-4溴苯乙烯）红细胞可以进一步化学定制附加其他化学功能。 一组分析探针，包括NMR、元素分析和克尔效应测量，将用于确定RBC中的化学组成和单体序列分布。 分析方法将补充使用蒙特卡罗模拟，这将揭示分子水平的洞察力的性质的“着色”过程的建模研究。 我们还提出了一种新的方法来制备红细胞的表面上的小二氧化硅球。 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/固体界面的吸附。 后一种方法的主要焦点是研究共聚物序列分布、聚合物/固体相互作用和基底的化学不均匀性之间的相互作用。 高空间分辨率的深度剖析技术，包括中子和X射线反射率，光谱椭圆偏振法，和离子束技术，将被应用与选择性氘标记结合探测的体积分数的轮廓和面内distributioin的红细胞在固/液和固/融界面。 拟议活动的内在价值：这项工作的主要成果将是证明红细胞，尽管其统计性质，能够执行类似于具有精确控制的单体序列分布的大分子的功能。 我们将证明，可以采用简单的化学着色方法，以产生具有广泛的化学性质和功能的RBC。 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有力的工具。 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对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应用的健康。 了解这种大分子的界面性能提供了前所未有的手段，设计新的材料和结构，可以找到广泛的，在各种软凝聚态物质的应用，包括纳米反应器，“种子”组织非聚合物纳米夹杂物中使用。 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艾里山小学的外联活动，并提出吸引当地K-12学生参加我们的跨学科研究奋进。

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.