Book Description

Graft conjugated polymers are exciting new materials with the potential to make a sustainable impact in a number of different applications from organic electronics, to bioimaging and photocatalysis. The ability to control the chemical composition, topology, and functionality of these materials at a molecular level allows them to be tuned for a desired application. Current research into conjugated polymers has focused on their use as flexible electronics in organic field effect transistors, organic photovoltaics, and organic electrochemical transistors. The ability of conjugated polymers to function as light emitting and electron donating materials has been overlooked. This dissertation focuses on designing a versatile approach towards graft conjugated polymer synthesis and investigating the polymers as light emitting and electron donating materials. We have designed a building block synthetic strategy for creating graft conjugated polymers with tailored optical properties. Utilizing a grafting-to approach, different conjugated polymer backbones and different side chains can be created and tethered together in any combination through copper-catalyzed azide-alkyne cycloaddition. Our synthetic approach was verified through the formation of a collection of graft polymers with polythiophene backbones. These new graft polymers were investigated as nanoparticles in aqueous media and have shown improved photoluminescence by decreasing aggregation through the change in architecture. The scope of our building block strategy was expanded to include new conjugated copolymer backbones containing electron-donating carbazole comonomers. Fully conjugated graft polymers with polythiophene side chains exhibited electron transfer between the donating carbazole chromophore and the accepting thiophene chromophore. The electron transfer allowed these polymers to be investigated as microenvironment sensors. Furthermore, considering the electron donating nature of carbazole, all the carbazole containing grafts were investigated as photocatalysts for the degradation of common organic dyes found in waste water. The ability to control the optical properties of graft conjugated polymers was further demonstrated by the synthesis of donor-acceptor copolymer backbones with different side chains. Utilizing different donor-acceptor combinations, the conjugated graft polymers absorbed photons at longer wavelengths. These grafts were then explored as photocatalysts for the degradation of organic dyes under visible light irradiation. Altogether, this work demonstrates the ability to easily manipulate the chemical composition of conjugated graft polymers for a desired application. The progress we have made on connecting the polymeric architecture to its optical properties will aid in the future design choices for polymer chemists and has laid the foundation of conjugated graft polymers as light emitting and electron donating materials.