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

第一部分：非技术性总结这项研究是关于一类被称为“多两性离子”的聚合物材料。它们由携带正电荷和负电荷的长链化学单元组成。一些新的具有不同化学结构的多两性离子将在实验室中设计和制造，然后进行研究，以找到最适合技术应用的。它们将接受热稳定性、机械强度以及吸水或拒水能力的测试。这些研究将为更合理地为各种应用开发新材料提供所需的知识基础。预计拟议的多两性离子研究将在重要方面造福社会。多两性离子可能用于生物医学用途，如水凝胶或伤口敷料。在净水领域，多两性离子可以改善滤膜的性能，从而产生更好的水处理系统。多两性离子分子在水或盐存在的情况下如何相互作用将是能源技术领域的重要信息，从而导致用于储能的新电池。妇女、少数群体和残疾人等代表不足的群体更多地参与STEM领域也将使社会受益(特别强调针对聋哑人和听力障碍本科生的方案)。第二部分：技术综述先进的热分析方法，如温度调制和快速扫描芯片量热法，将被用于以磺基甜菜碱型两性离子基团为特征的多两性离子(PZI)的热物理性质的基础研究。热测量将通过结构表征得到加强。其技术目标是：1.合成一系列多两性离子，并研究浇铸膜的基本热学性质与化学链结构和盐含量的变化的关系；2.使用快速扫描量热法测量PZI的基本热学性质，以最大限度地减少降解的影响；3.研究PZI的结构与形成链内和链间交联度的盐含量的函数关系，这可以调节这种交联性。将进行高精度、高精度的热容测量，以量化固体和液体状态，以及它们与结合水和盐含量的关系。具体地说，将研究LiCl盐对PZI的热性能和结构性能的影响。温度调制差示扫描量热法将在PZI铸膜上进行，以提供基本的热性能，如固态热容。采用差示快速扫描切片量热法对这些材料在2000K/S下进行研究，以避免降解，得到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。在存在或不存在添加盐的情况下，将研究PZI的玻璃形成能力。材料的结构将使用广角和小角X射线分析和傅里叶变换红外光谱进行评估。教育和外展活动将包括为聋人和听力障碍实习生提供暑期实习计划。这一奖励反映了NSF的法定使命，并通过使用基金会的智力优势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 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.