Main Group Catalysis for Sustainable Piezoelectrics

目标的总体项目是研究新的主族催化剂是否可以用于生产具有有趣的可调性能的可持续铁电材料。在该项目中，将研究利用N-杂环膦化合物（NHP-X）的极性对丙交酯和其他环酯进行开环聚合（ROP）研究（与洛斯阿拉莫斯国家实验室合作）。除了文献中报道的5元NHP-X催化剂之外，一系列新的催化剂支架将被应用于研究N-取代基、P-取代基、N-P-N角和π-离域对所得聚酯的聚合物性质的影响。改变由NHP催化剂提供的聚酯的微观结构（即立构规整度、链长、端基、制备共聚物的能力）的能力提供了开发结构-活性关系和测量此类聚合物的铁电性质的独特机会。目标1：研究已知和新的NHP-X物种在ROP和其他反应性中的催化功效。（使用标准的空气敏感化学技术，包括Schlenk技术，并利用分析化学方法进行表征，如核磁共振（NMR）光谱法，质谱法和单晶X射线衍射。目的2：探讨单体范围、稳定性和解聚潜力。（将监测聚合反应，并使用NMR光谱、差示扫描量热法、粉末X射线衍射和MALDI-TOF质谱等技术分析产品。目的3：研究NHP-X衍生聚合物的介电和铁电性能。（聚合物的铁电，热电和压电特性将与机械工程系合作测量，通过测量材料在电场，温度变化和压力下的极化变化。

The overall project of the goal is to investigate whether new main group catalysts can be used to produce sustainable ferroelectric materials with interesting tuneable properties.In this project, the exploitation of the polar nature of N-Heterocyclic phosphine compounds (NHP-X) to undertake ring-opening polymerisation (ROP) studies on lactide and other cyclic esters (in concert with Los Alamos National Lab) will be investigated. Beyond the 5-membered NHP-X catalysts reported in the literature, a range of new catalyst scaffolds will be applied to investigate the effect of N-substituent; P-substituent; N-P-N angle and pi-delocalisation upon the polymer properties of the resulting polyester. The ability to vary the microstructure of polyesters offered by NHP catalysts (i.e. tacticity, chain length, end groups, ability to prepare copolymers) provides a unique opportunity to develop structure-activity relationships and measure the ferroelectric properties of such polymers. Aims of the project:Aim 1: Investigation of the catalytic efficacy of known and new NHP-X species in ROP and other reactivity. (Using standard air sensitive chemistry techniques including Schlenk techniques, and utilising analytical chemistry methods for characterisation such as nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry and single crystal X-ray diffraction.) Aim 2: Interrogation of monomer scope, valorization and depolymerization potential. (Polymerisations will be monitored and the products will be analysed using techniques such as NMR spectroscopy, differential scanning calorimetry, powder X-ray diffraction and MALDI-TOF mass spectrometry.) Aim 3: Investigation of the dielectric and ferroelectric properties of NHP-X derived polymers. (Ferroelectric, pyroelectric and piezoelectric properties of the polymers will be measured in collaboration with the Department of Mechanical Engineering, by measuring the change in polarisation of the material under the application of electric field, temperature change and pressure.)