Author: Stephen KoehlerPublisher:
ISBN:
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Languages : en
Pages : 0
Book Description
Donor-Acceptor poly(p-arylenevinylenes) (DA PAVs) are an untapped class of materials owing largely to their challenging synthesis. The Elacqua group recently reported the synthesis of such polymers by Ring-Opening Metathesis Polymerization (ROMP). The newly synthesized monomer polymerized with good control over molecular weight and was able to form block copolymers with poly(norbornene). In Chapter 2, the inherent steric and electronic bias of ROMP is leveraged within the same monomer scaffold to study how to monitor and influence polymer sequence. A combination of monomer steric bulk, reaction solvent, and temperature are all variables that can influence the sequence. While further study is needed, non-symmetric substitution of alkyl chains appears to be important in achieving controlled polymerizations. This comes with many limitations, namely a challenging monomer synthesis, for which we provide some perspective and insight to overcome this deficit. Given the remaining synthetic challenges, computational chemistry will be a particularly powerful tool to deliberately identify synthetic targets. Simulating polymer properties is a difficult task in itself; in Chapter 3, a high throughput screening method which is both more accurate and an order of magnitude faster than leading quantum mechanical methods was developed. Preliminary data supports a size-parameter relationship between monomers, which could be leveraged to further enhance the accuracy, and potentially used in simulating higher-dimensional conjugated structures like covalent organic frameworks. Circling back to screening-driven polymer design, Chapter 4 presents time-dependent density functional theory calculations that identify DA PAVs as a promising class of materials for singlet fission. This is due, in part to the planarization afforded by the vinyl-spacer. This is observed both when replicating reported methods, as well as when applying the high throughput screening capabilities developed in Chapter 3. Chapter 5 looks toward multifunctional devices or stimuli responsive organic electronics, wherein the synthesis of thiophene-appended spiropyran oligomers which can reversibly change their band gap energy are presented. The observed band gap energies agree well with DFT calculations, suggesting more diverse spiropyran-oligomers could be explored. However, fast isomerization with oligomer-appended spiropyran was not observed, though it is hypothesized that spirothiopyran could be an effective tool to overcome this. Overall, this work demonstrates progress in both synthetic and computational methodology to advance the development and discovery of organic electronic materials.
Author: Stephen Koehler