The design and synthesis of polymeric assemblies for materials applications : chemosensing, liquid crystal alignment and block copolymers

Abstract

Conjugated polymers are an indispensable class of materials that have advanced the development of optoelectronic device architectures; in part, due to their outstanding electronic and mechanical properties. This thesis explores the utility of rationally designed energy transfer cascades involving conjugated polymers that can be used in applications such as chemosensing and liquid crystal alignment. We begin by describing the design and development of a new transduction mechanism for the detection of cyclic ketones - molecules that are found in plasticized explosives. We discuss the synthesis of a new reporter dye bearing a receptor for cyclic ketones that is capable of undergoing efficient energy transfer with conjugated polymers. We further describe the optimization of a thin-film sensor comprised of these two components as well as its performance and selectivity. In the next chapter we describe the design and synthesis of two new polymers that are capable of undergoing the di-[Pi]-methane rearrangement. We begin by describing the synthesis and photochemistry of the polymers as well as a model compound. The polymers contain triplet sensitizers built into the polymer backbone thereby creating an energy transfer cascade that facilitates the di-a-methane rearrangement. These materials are then evaluated as liquid crystal alignment layers for optoelectronic applications. In the final chapter, we describe the end-capping of cross-coupling polymerizations using the hydroarylation of norbornadiene. This reaction is shown to be an efficient approach to generating macroinitiators which can be further polymerized using ring opening metathesis polymerization. These end-capped materials can also be crosslinked into hybrid materials that show promise as thin-film sensors for volatile organic compounds.