Doctor of Philosophy (PhD)
Conjugated polymers (CPs) have been widely investigated for their remarkably high sensitivity towards various chemical detection applications. CPs can exhibit effective transduction of certain analyte binding events through changes in fluorescence. These changes include amplified fluorescence quenching ("turn-offmechanism") or an appearance of a fluorescent emission ("turn-onmechanism"). Whereas turn-offsensors can be readily designed and are widely used, amplifying turn-onsensors, from a practical standpoint, are more convenient to use but are more challenging to design.
This dissertation primarily focuses on the development and study of conjugated polymer based amplifying turn-onfluorescence chemosensors utilizing the novel “higher energy gap” control concept as well as further investigation of the scope of applicability and generality of this concept. The higher energy gap control paradigm that relies on relatively minor changes in the electronic nature of the receptor site upon its reaction with analytes could offer a general and universal approach towards using conjugated polymers as a platform for the design of amplifying turn-onfluorescent chemosensors. To expand the practical applicability of the higher energy gap paradigm, singlet oxygen and cysteine were chosen as target analytes as they areimportant biochemical and industrial analytical targets.
The last chapter of this dissertation involves the design of a novel nanoscale hybrid system consisting of silica core and fluorescent triblock copolymer shell which is prepared via surface-initiated Kumada catalyst transfer polymerization. Although this project is not directly related to the “higher energy gap” concept, these studies can help in better understanding the fundamental mechanisms behind the design of chemo- and biosensors.
Wang, Chun-Han, "Chemosensors Based on Higher Energy Gap Control of Fluorescence in Conjugated Polymers" (2019). LSU Doctoral Dissertations. 4980.