CAREER: Electric Field Processing of Polyelectrolyte Complex

职业：聚电解质复合物的电场处理

• 批准号: 1255612
• 负责人: Nicole Zacharia
• 金额: $ 40万
• 依托单位: Texas A&M Engineering Experiment Station
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-03-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1255612&HistoricalAwards=false
• 关键词: CAREER; Electric; Field; Processing; Polyelectrolyte

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.

技术概述：根据该奖项进行的工作是检查合成多电解质复合物溶液的相行为，然后使用电场在溶液中操纵这些复合物，目的是将它们作为固体沉积到基板上。将对通常用于多层聚电解质（如聚丙烯酸、磺化聚苯乙烯、聚烯丙胺盐酸盐和聚亚胺）的逐层（LbL）组装的合成聚电解质（包括强聚电解质和弱聚电解质）进行检查。工作的第一部分将是确定不同对聚电解质复合物的相图，作为pH值、溶液离子强度、分子量和浓度的函数。这些配合物的热力学行为通常被动力学因素所掩盖，解开这些成分将是一个目标。下一阶段的工作将是观察不同化学计量的配合物在带电表面上的吸附。工作的第三阶段将比较这种平衡吸附和在电场影响下在带电表面上的沉积。考察的因素包括离子强度、溶剂介电常数和其他成分（如金属纳米粒子）的加入。这一过程最终将被推广到其他类型软物质的电泳沉积，如胶束或中空聚电解质胶囊。工作的最后一个阶段是检查由这个过程产生的固体材料。假设不同的化学计量和性质可以通过电场操作来实现，而不是在表面上的平衡吸附。非技术概述：聚电解质（PEs）可以比较非常长的分子盐，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。生物材料如蛋白质和DNA就是聚电解质的例子。通过顺序吸附步骤技术，pe可以加工成具有一系列非常有用性能的薄涂层。这些涂料有可能应用于替代能源设备、生物医学设备、窗户节能涂料和任何其他可能性。它们商业化的一个主要障碍是制造这些涂层需要很长时间。这里提出的工作是把电场作为一种工具来提高聚电解质制成的涂层的沉积时间。这种潜力对这些材料的商业可行性产生了影响。这项工作将有助于培养博士生和本科生，使他们从事科学工作。外联工作将在考虑转入四年制大学的社区大学学生中进行。将特别重视对来自代表性不足群体的本科生和研究生的指导，特别是女学生和家庭中第一个上大学的学生。PI在与这些团体的学生合作方面已经有了良好的记录。