Photochemical Sciences Ph.D. Dissertations

Understanding Light Driven Processes in Molecules and Materials

Date of Award

2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Photochemical Sciences

First Advisor

Jayaraman Sivaguru, (Committee Chair)

Second Advisor

Pavel Anzenbacher (Committee Member)

Third Advisor

Malcolm D. E. Forbes (Committee Member)

Fourth Advisor

Amy L. Morgan (Other)

Abstract

The interaction of molecules and materials with light can transform the chemical nature besides the physical phenomena. Investigation of these transformations for better cognizance of light mater interaction is significant. Chapter 2 will present a novel and new excited state reactivity of aryl maleimides that go through a [2+4] photodimerization utilizing visible light irradiation, instead of the established [2+2]-photodimerization. The [2+4] photodimerization of arylamides was established under both direct and sensitized conditions. Typically, light-mediated reactions proceed through electron transfer / energy transfer in case of sensitized (photocatalyzed) reactions. This new reactivity is investigated and reported using various photochemical and photophysical studies. Employing light as a green reagent for various transformations and development of novel green polymerization strategies is discussed in Chapter 3. Photoinitiators are relevant components in photopolymerization. Biomass derived and visible light activated photoinitiators are fascinating new technology when compared to fossil fuel derived UV-active photoinitiators. UV-light is hazardous and cause energy wastage. Chapter three will detail the synthesis of biomass derived photoinitiators that are effective in promoting polymerization under visible light irradiation. Based on photopolymerization and photophysical data, these new visible light active biomass derived photoinitiators are shown to have superior optical properties compared to conventional fossil fuel derived photoinitiators with similar functionality. Chapter 4 will detail the development of stabilizers for electronically dimmable eyewear, that features dye dopped liquid crystal (LC) scaffolds. The photodegradation of the LC materials were investigated and suitable stabilizers were evaluated to slow the degradation process. Chapter 5 will also highlight studies related to the photodegradable polymers that are synthesized from bioresources. With growing concern towards plastic degradability, the idea of photodegradation and recyclability of the polymer gives promise. The green process of upcycling the biomass derived cross linked polymer by utilizing light is being discussed in the thesis with the support of quantum yield studies.

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