Fundamental Energetics and Transmembrane Nanostructuring in Polyelectrolyte Membranes

复杂的聚电解质，包括那些通过“多层”技术形成的超薄膜，呈现出一种迷人的软凝聚态物质。结构上扩散，多折衷多层材料提供了无与伦比的组成灵活性和许多有前途的应用。本提案旨在解决聚电解质多层和复合物的单一最重要的定量描述：表征盐膨胀的平衡常数。膨胀在多层膜的生长中起着关键作用，当它们用作膜时，它们的运输特性，它们的稳定性以及在加工，微图案和细胞粘附促进剂中的应用。在一种新的方法中，将评估不同组合的聚电解质的膨胀常数，以获得单个聚电解质段离子配对的特征自由能。“相互作用能”可以用来预测任何聚电解质组合的膨胀性能，以及由此产生的性能，无论是在超薄膜中还是在其他形态中。结合对基础聚合物物理化学的探索，并在纳米生物技术的精神下，引入选择性纳米结构离子通道的新方法将被开发出来，这些离子通道将由疏水性梯度有序和定向。这种离子传导多肽被设计成垂直于表面，将为纳米多层结构开辟第三个维度。多层聚电解质和其他带电的纳米物质是一种使能技术。低要求的设备要求和功能和组成的可能性的有力结合刺激了跨学科的研究和教育。多层材料对技术的影响已经在纳米结构、生物技术、药物释放和表面修饰等不同领域得到了广泛的应用。这一分两部分的建议提供了双重范式：一是在一个快速发展的领域中提出一个基本的统一概念，另一个是在结构和结构上提出一个新的范式。这项工作以易于理解的概念为基础，通过追踪和提供代表多层和多电解质复合物物理化学本质的平衡常数，将对该领域产生最广泛的影响。对具有悠久历史的聚电解质复合物的性质进行合理化和预测，将有助于它们进入技术上有用的分子构建块的领域和词典。利用疏水性梯度来指导纳米结构组装提供了层间通信，当多层用于制造分隔的分层结构时，这是一门新兴的科学。

Complexed polyelectrolytes, including those formed into ultrathin films by the "multilayering" technique, present a fascinating phase of soft condensed matter. Structurally diffuse, polyeclectrolyte multilayers offer unparalleled compositional flexibility and a host of promising applications. This proposal seeks to address the single most important quantitative descriptor of polyelectrolyte multilayers and complexes: the equilibrium constant characterizing swelling by salt. Swelling plays a pivotal role in the growth of multilayers, their transport properties when used as membranes, their stability and this use in processing, micropatterning and cell adhesion promoters. In a novel approach, swelling constants will be evaluated for different combinations of polyelectrolytes to arrive at a characteristic free energy of ion pairing for a single polyelectrolyte segment. The "interaction energy" may be used to predict the swelling performance, and properties flowing therefrom, of any combination of polyelectrolytes, whether in ultrathin films or other morphologies. Coupled with this foray into fundamental polymer physical chemistry, and in the spirit of nano-biotechnology, new methods for introducing selective nanostructured ion channels, ordered and oriented by hydrophobicity gradients, will be developed. The proposed ion conducting polypeptide, designed to run perpendicular to the surface, will literally open up a third dimension for nanostructuring multilayers.The multilayering of polyelectrolytes and other charged nanoscopic species is an enabling technology. A potent combination of undemanding equipment requirents and functional and compositional possibilities has stimulated interdisciplinary research and education. The impact of multilayers on technology is already evidenced by a broad range of proposed and realized applications in diverse fields such as nanostructuring, biotechnology, drug release and surface modification. This two-part proposal offers dual paradigms: one, a fundamental unifying concept in a rapidly expanding field, the other, a new paradigm in structure and structuring. The proposed work, whose logistics are underpinned by easily digested concepts, will have the broadest possible impact on the field by tracking down and making available the equilibrium constants which represent the essence of the physical chemistry of multilayers and polyelectrolyte complexes in general. Rationalization and prediction of the properties of polyelectrolyte complexes, materials with a venerable history, will assist them in entering the realm and lexicon of technologically useful molecular building blocks. The use of hydrophobicity gradients to direct nanostructure assembly provides for interlayer communication when multilayers are used to fabricate compartmentalized hierarchical structures, an emerging science.