Equilibrium Parameters of Polyelectrolyte Complex Coacervates

第1部分：非技术概述具有带电化学基团的聚合物，称为聚电解质，在自然界和技术中随处可见。因为它们是带电的，这些聚合物溶解在水中，大大增加了粘度。当相反电荷的聚电解质混合时，它们缔合以产生新材料，聚电解质络合物或佩奇，具有作为用于纯化的膜、生物医学材料、抗静电涂层和防水粘合剂的潜在应用。盐有助于放松带相反电荷的聚合物之间的吸引力，使材料能够加工成所需的形状。所有这些有价值的应用都取决于如何通过选择材料和加工条件来设计这些佩奇的性能。这项研究将揭示三个参数必不可少的理解佩奇的响应和性能。首先，通过用重原子标记聚合物链，将在材料内部测量已知在无定形PEC内纠缠的聚合物线圈的大小。其次，将研究盐在主动破坏聚合物电荷之间的相互作用中的效率，而不是被动地坐在电荷附近。最后，将用超精密分析技术测定盐对佩奇的水、盐和聚合物含量的影响。除了作为国内学生的培训工具外，该项目还将跨越各大洲，让法国和尼日利亚的同事和学生参加关于聚电解质和现代聚合物科学和技术其他方面的研讨会。 第二部分：技术概述聚电解质凝聚/络合（佩奇）是液/液相分离的一个子集，当两种电荷相反的聚电解质混合时发生。该系统代表带电聚合物的水合共混物，其特征与水凝胶和中性聚合物的经典共混物重叠。这种形态在分离/纯化、生物医学材料、生物涂层、能量转换和防水粘合剂等领域提供了新的应用。材料及其性质也是物理学、化学、生物学和材料领域对液/液相分离的强烈兴趣的交叉点。要深入了解佩奇的性质，需要了解许多参数，这些参数既是聚合物科学的基础，也是佩奇独有的。这项研究将精确测量三个重要参数。首先，将使用一系列窄分子量分布的氘代聚电解质来确定聚合物线圈尺寸作为分子量的函数的缩放。第二个领域解决了当盐离子进入PEC以破坏正负重复单元之间的配对时盐离子发生的中心不确定性：每个离子是否破坏一对，或者一些离子是否只是为了平衡PEC和溶液之间的渗透压而存在。在最后一个子项目中，将制备一系列用C-14放射性标记的短链长度聚电解质，并用于高度精确和准确的放射性分析方法，以确定PEC相图作为分子量的函数。所有这些参数都需要为新兴的理论处理提供可靠的数据。除了作为国内学生的培训工具外，该项目还将跨越各大洲，让法国和尼日利亚的同事和学生参加关于聚电解质和现代聚合物科学和技术其他方面的研讨会。 该奖项反映了NSF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。

PART 1: NON-TECHNICAL SUMMARYPolymers having electrically charged chemical groups, called polyelectrolytes, are seen throughout nature and technology. Because they are charged, these polymers dissolve in water, substantially increasing viscosity. When polyelectrolytes of opposite charge are mixed, they associate to give new materials, polyelectrolyte complexes or PECs, with potential applications as membranes for purification, biomedical materials, antifouling coatings, and waterproof adhesives. Salt helps to loosen the attractions between oppositely charged polymers, allowing the material to be processed into desired shapes. All of these valuable applications depend on how the properties of these PECs can be designed by choice of materials and processing conditions. This research will shed light on three parameters essential to understanding the response and performance of PECs. First, the size of polymer coils, known to be entangled within the amorphous PEC, will be measured inside the material by labeling polymer chains with heavy atoms. Second, the efficiency of salt in actively breaking interactions between polymer charges, as opposed to passively sitting near the charges, will be investigated. Finally, the influence of salt on water, salt and polymer content of PECs will be measured with ultraprecise analytical techniques. In addition to serving as a training vehicle for domestic students, this project will reach out across continents, engaging colleagues and students in France and in Nigeria in seminars on polyelectrolytes and other aspects of modern polymer science and technology. PART 2: TECHNICAL SUMMARYPolyelectrolyte coacervation/complexation, PECs, a subset of liquid/liquid phase separation, occurs when two polyelectrolytes of opposite charge are mixed. The system represents a hydrated blend of charged polymers with characteristics overlapping both a hydrogel and a classical blend of neutral polymers. This morphology offers novel applications in the areas of separations/purification, biomedical materials, antifouling coatings, energy conversion, and waterproof adhesives. The materials and their properties also lie at the intersection of intense interest in liquid/liquid phase separation from the physics, chemistry, biology and materials fields. A deep understanding of the properties of PECs requires knowledge of many parameters both fundamental to polymer science and unique to PECs. The proposed research will accurately measure three important parameters. First, the scaling of the polymer coil size as a function of molecular weight will be determined using a series of narrow molecular-weight-distribution deuterated polyelectrolytes. The second area addresses the central uncertainty of what happens to salt ions when they enter a PEC to break pairing between positive and negative repeat units: whether each ion breaks a pair or whether some of the ions are simply present to balance the osmotic pressure between PEC and solution. In the final subproject, a series of short-chain-length polyelectrolytes, radiolabeled with C-14, will be prepared and employed in highly precise and accurate radioanalytical methods to determine a PEC phase diagram as a function of molecular weight. All of these parameters are needed to supply the burgeoning theoretical treatments with reliable data. In addition to serving as a training vehicle for domestic students, this project will reach out across continents, engaging colleagues and students in France and in Nigeria in seminars on polyelectrolytes and other aspects of modern polymer science and technology. .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.