CAREER: Electric Field Processing of Polyelectrolyte Complex

技术摘要：本奖项将开展的工作是研究合成聚电解质络合物溶液的相行为，然后使用电场在溶液中操纵这些络合物，目标是将它们作为固体沉积到基质上。本课程将考察通常用于聚电解质多层(如聚丙烯酸、磺化聚苯乙烯、聚烯丙基胺盐酸盐和聚乙烯亚胺)逐层组装的合成聚电解质，包括强聚电解质和弱聚电解质。工作的第一部分将是确定不同对聚电解质的络合物的相图作为pH、溶液离子强度、相对分子质量和浓度的函数。这些络合物的热力学行为通常被动力学考虑所掩盖，而解开这些组分将是一个目标。下一阶段的工作将是观察不同化学计量比的络合物在带电表面的吸附。这项工作的第三阶段将是比较这种平衡吸附和在电场影响下沉积在带电表面上的情况。这些因素包括离子强度，溶剂的介电常数，以及其他成分的添加，如金属纳米颗粒。这一过程最终将被推广到研究其他类型软物质的电泳沉积，如胶束或中空聚电解质胶囊。这项工作的最后阶段是检查这个过程产生的固体材料。与平衡吸附在表面上相比，通过电场操作可以获得不同的化学计量比和性质。非技术摘要：聚电解质(PES)可以被比作非常长的分子盐，即由一系列正电荷或负电荷组成的长链分子。它们往往是水溶性的，经常用于制药、化妆品或食品配方中。蛋白质和DNA等生物材料是聚电解质的例子。通过顺序吸附步骤的技术，PE可以加工成具有一系列非常有用的特性的薄涂层。这些涂层可能在替代能源设备、生物医疗设备、窗户节能涂层以及任何其他可能性中应用。它们商业化的一个主要障碍是制造这些涂料需要很长的时间。这里提出的工作是将电场作为一种工具来提高由聚电解质制成的涂层的沉积时间。这种潜力具有使这些材料在商业上可行的影响。这项工作将有助于培养博士生和本科生，使他们从事科学。将在考虑转到四年制项目的社区大学学生中开展外联活动。将特别重视对来自代表不足群体的本科生和研究生，特别是女学生和家庭中第一个上大学的学生的辅导。国际学生联合会在与这些团体的学生合作方面已经有了很好的记录。

TECHNICAL SUMMARY: The work to be conducted under this award is to examine phase behavior of solutions of synthetic polyelectrolyte complexes and to then use an electric field to manipulate these complexes in solution with the goal of depositing them as solids onto substrates. Synthetic polyelectrolytes, both strong and weak, that are typically used in layer-by-layer (LbL) assembly of polyelectrolyte multilayers (such as polyacrylic acid, sulfonated polystyrene, polyallylamine hydrochloride, and polyethylene imine) will be examined. The first part of the work will be to determine phase diagrams for the complexes of different pairs of polyelectrolytes as a function of pH, solution ionic strength, molecular weight, and concentration. The thermodynamic behavior of these complexes is generally masked by kinetic considerations, and unraveling these components will be one goal. The next phase of the work will be to look at adsorption of complexes of different stoichiometries onto charged surfaces. The third phase of the work will be to compare this equilibrium adsorption to deposition onto charged surfaces under the influence of an electric field. Factors including ionic strength, dielectric constant of the solvent, and addition of other components such as metal nanoparticles will be examined. This process will eventually be generalized to look at the electrophoretic deposition of other types of soft matter such as micelles or hollow polyelectrolyte capsules. The last phase of the work is to examine the solid materials created by this process. It is hypothesized that different stoichiometries and properties can be achieved through electric field manipulation as compared to equilibrium adsorption onto a surface.NON-TECHNICAL SUMMARY: Polyelectrolytes (PEs) can be compared very long molecular salts, i.e. long-chain molecules made up of a sequence of either positive or negative charges. They tend to be water-soluble and are often used in pharmaceutical, cosmetic, or food formulations. Biological materials such as proteins and DNA are examples of polyelectrolytes. PEs can be processed into thin coatings with a range of very useful properties by a technique of sequential adsorption steps. These coatings have possible applications in alternative energy devices, biomedical devices, energy saving coatings for windows, and any number of other possibilities. One major barrier to their commercialization is the long time required to make these coatings. The work proposed here is to look at electric fields as a tool to enhance the deposition times for coatings made of polyelectrolytes. This potential has the impact to make these materials commercially viable. This work will help to train PhD students as well as undergraduate students, to engage them in science. Outreach will be done with community college students who are considering transferring into four-year programs. Special attention will be paid to the mentoring of undergraduate and graduate students from under-represented groups, especially female students and those students who are the first in their family to attend college. The PI already has a strong record of working with students from these groups.