Main Group Catalysis for Sustainable Piezoelectrics

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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.)