Selective Fundamental Problems in Supramolecular Assembly and Phase Stability of Homopolymer Mixtures

芝加哥大学的卡尔·弗里德获得了化学理论、模型和计算方法项目的一个奖项的支持，以研究自组装和相关现象。平衡自组装涉及分子自发组织成显示有序的更大结构，是化学，材料科学和生物学中普遍存在的现象。因此，控制这种自组装的能力在工业和医学上有许多应用。通过平衡自组装形成的大量复杂功能结构表明，对基本原理的理解可以在设计真正新颖的材料和医学疗法方面具有变革性。这激发了许多先进的合成自组装系统的实验研究，如纳米颗粒，肽和DNA复合物，大分子系统合成的变革策略的发展，具有特定性质的超分子系统的合成，以及分子和大尺度粒子自组装的计算机模拟。 最后是本项目的工作重点。自组装分析建模的快速增长有望推动应用向前发展，因为人们学会利用自然界长期利用的丰富原理来创造高度响应和功能性的自组织和自修复材料。这些进展可以大大提高有关软物质，纳米技术，生物技术，医学等各种问题的知识，并且当扩展到非平衡自组装时，可以解决生命系统和细胞运动和通信等基本过程的发展。目前的建议代表了一个长期的研究计划，致力于发展基础理论预测的热力学性质的均聚物混合物和解决方案，包含物种，可以相互关联或与溶剂的高潮。这两种类型的关联导致在化学平衡下形成可变大小的簇。理论方法是基于扩展的Flory-Huggins（FH）理论自组装或更详细的晶格簇理论（LCT），其中包括FH理论忽略的分子特征的描述，如单体的大小和形状，链刚度，和可压缩性的影响。LCT最近被扩展到描述强相互作用的遥爪聚合物（具有粘性端基的聚合物）的溶液。该理论旨在阐明生命系统中许多结构上重要的结合过程的一般效应，这些过程受到周围链、限制表面和结合分子（例如，调节组装体稳定性的蛋白质）。相互关联，聚合物的溶解性和疏水性的共同的一般机制强调溶剂化/结合的拟议研究的基本性质。竞争性分子结合在洗脱色谱、材料合成和生物过程中也具有重要意义。拟议的研究概述了一个广泛的理论框架，用于开发理论，可以帮助合理设计新材料，新药物系统和物理疗法，以减轻与自组装故障相关的疾病。

Karl Freed at the University of Chicago is supported by an award from the Chemical Theory, Models and Computational Methods Program to study self-assembly and related phenomena. Equilibrium self-assembly involving the spontaneous organization of molecules into larger structures that show order is a ubiquitous phenomenon pervading chemistry, materials science, and biology. Hence, the ability to control this self-assembly has numerous applications for industry and medicine. The vast array of complex functional structures formed through equilibrium self-assembly suggests that an understanding of the underlying principles can be transformative in designing truly novel materials and medical therapies. This has motivated numerous advanced experimental studies of synthetic self-assembling systems such as nanoparticles, peptides and DNA complexes, the development of transformative strategies for synthesis of macromolecular systems, the synthesis of supramolecular systems with specific properties, and computer simulations of the self-assembly of molecular and larger-scale particles. The last is a focus of the work in the current project. The rapid growth of analytical modeling of self-assembly promises to drive applications forward as one learns to exploit the rich palette of principles, long utilized by nature, to create highly responsive and functional self-organizing and self-healing materials. These advances can greatly improve knowledge concerning diverse problems in soft matter, nanotechnology, biotechnology, medicine, and, when extended to non-equilibrium self-assembly, allow addressing basic processes such as the development of living systems and cell locomotion and communication. The current proposal represents the culmination of a long term research program devoted to developing fundamental theories for predicting thermodynamic properties of homopolymer mixtures and of solutions containing species that can associate with each other or with solvent. Both types of association lead at chemical equilibrium to the formation of clusters of variable size. The theoretical approaches are based either on extensions of Flory-Huggins (FH) theory to self-assembly or on the more detailed lattice cluster theory (LCT), which includes a description of molecular features neglected by FH theory, such as monomer size and shape, chain stiffness, and compressibility effects. The LCT has recently been extended to describe solutions of strongly interacting telechelic polymers (polymers with sticky end groups). The theory aims at elucidating the generic effects of many structurally important binding processes in living systems that are greatly influenced by surrounding chains, confining surfaces, and binding molecules (e.g., proteins that modulate the stability of assemblies). The common general mechanism of mutual association, polymer solubility and hydrophobicity stresses the fundamental nature of the proposed studies of solvation/binding. Competitive molecular binding is also of central significance in elution chromatography, materials synthesis, and biological processes. The proposed research outlines a broad theoretical framework for developing theories that can assist in the rational design of new materials, new drug systems, and physical therapies to mitigate against diseases associated with malfunctioning self-assembly.