Thermal and Structural Properties of Polyzwitterions, with Research Opportunities for Deaf and Hard of Hearing Interns

第一部分： 非技术概述本研究是关于一类称为“聚两性离子”的聚合物材料。 它们由带有正电荷和负电荷的化学单位的长链组成。 许多新的聚两性离子将在实验室中设计和制造具有不同化学结构的，然后研究以找到最佳的技术应用。它们将被测试热稳定性，机械强度和吸收或拒绝水的能力。这些研究将为更合理地开发一系列应用的新材料提供所需的知识基础。预计拟议中的对两性离子的研究将以重要的方式造福社会。聚两性离子可用于生物医学用途，例如水凝胶或伤口敷料。在水净化领域，两性离子可以改善过滤膜的性能，从而产生更好的水处理系统。在水或盐的存在下，聚两性离子分子如何相互作用将成为能源技术领域的重要信息，从而产生用于能量存储的新型电池。社会利益也将来自代表性不足的群体，如妇女，少数民族和残疾人（特别强调针对聋人和听力困难的大学生的计划）的人越来越多地参与STEM领域。第二部分： 技术概述先进的热分析方法，如温度调制和快速扫描芯片量热法，将用于以磺基甜菜碱型两性离子部分为特征的聚两性离子（PZI）的热物理性质的基础研究。热测量将增加结构表征。技术目标是：1。合成了一系列聚两性离子，研究了化学链结构和盐含量变化对铸膜基本热性能的影响; 2.使用快速扫描量热法测量PZI的基本热性质以使降解的影响最小化; 3.研究PZI的结构，相对于作为盐含量的函数的链内和链间交联的形成，其可以介导这种交联。将进行高精度、高准确度的热容测量，以量化固体和液体状态及其对结合水和盐含量的依赖性。具体而言，氯化锂盐的作用将被调查，其对PZI的热性能和结构性能的影响。将对PZI流延膜进行温度调制差示扫描量热法，以提供基本的热性能，如固态热容。差示快速扫描芯片量热法将用于在2000 K/s下研究这些材料以避免降解，以获得干态玻璃化转变温度、液态热容和玻璃化转变时的热容增量。将研究PZI在存在或不存在添加盐的情况下的玻璃形成能力。材料的结构将使用宽角和小角X射线分析和傅里叶变换红外光谱进行评估。教育和推广活动将包括为聋人和听力困难的实习生提供暑期实习计划。该奖项反映了NSF的法定使命，并被认为是值得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的支持。

PART 1: NON-TECHNICAL SUMMARYThis research is on a class of polymeric materials called "polyzwitterions". They consist of long chains of chemical units that carry both positive and negative charges. A number of new polyzwitterions will be designed and made in the laboratory with different chemical structures, and then studied to find the best ones for technological applications. They will be tested for heat stability, mechanical strength, and ability to absorb or reject water. The studies will provide a knowledge base which is needed to more rationally develop new materials for a range of applications. It is expected that the proposed research on polyzwitterions will benefit society in important ways. Polyzwitterions may be useful for biomedical uses such as hydrogels or wound dressings. In the field of water purification, polyzwitterions may improve the properties of filtration membranes leading to better water treatment systems. How polyzwitterion molecules interact with each other in the presence of water or salts will be important information for the field of energy technology, leading to new batteries for energy storage. Societal benefit will also be derived from increasing participation in STEM fields of persons from under-represented groups, such as women, minorities, and persons with disabilities (with particular emphasis on a program aimed at deaf and hard-of-hearing undergraduates). PART 2: TECHNICAL SUMMARYAdvanced methods of thermal analysis, such as temperature modulated and fast scanning chip calorimetry, will be used for fundamental studies of thermo-physical properties of polyzwitterions (PZIs) featuring sulfobetaine-type zwitterionic moieties. Thermal measurements will be augmented with structural characterization. The technical objectives are to: 1. synthesize an array of polyzwitterions and investigate fundamental thermal properties of cast films in relationship to variations of chemical chain structure and content of salt; 2. measure fundamental thermal properties of PZIs using fast scanning calorimetry to minimize effects of degradation; 3. investigate the structure of PZIs with respect to formation of intra- and interchain cross-linking as functions of salt content, which can mediate this cross-linking. High precision, high accuracy heat capacity measurements will be made to quantify the solid and liquid states, and their dependence upon bound water and salt content. Specifically, the role of LiCl salt will be investigated as to its impact on the thermal and structural properties of PZIs. Temperature modulated differential scanning calorimetry will be performed on PZI cast films to provide fundamental thermal properties such as the solid state heat capacity. Differential fast scanning chip calorimetry will be used to study these materials at 2000 K/s to avoid degradation, to obtain the dry-state glass transition temperature, liquid-state heat capacity, and heat capacity increment at the glass transition. Glass forming ability will be studied for PZIs in the presence or absence of added salt. Structure of the materials will be evaluated using wide and small angle X-ray analysis and Fourier Transform infrared spectroscopy. Educational and outreach activities will include a summer internship program for deaf and hard-of-hearing interns..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.