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Dissertation Proposal Defense – Augustus Lang
MSE Grad Presentation
Monday, January 29, 2018 - 10:00am
Committee Members: Prof. John R. Reynolds, Advisor, CHEM, MSE Prof. Lars Berglund, FTP (KTH) Prof. Robert J. Moon, RBI, MSE Prof. Elsa Reichmanis, CHBE, MSE Prof. Natalie Stingelin, MSE, CHBE
"Morphology and Structural Control of Redox-Active Conjugated Polymers Using Cellulosic Substrates"
Redox-active conjugated polymers have been actively studied for use in a variety of technologies including electrochromic devices, supercapacitors, light emitting electrochemical cells, and electrochemical transistors. In these devices, efficient transport of both ions and electrons must occur throughout the conjugated polymer film requiring coexisting morphologies for each mode of transport. As material for imparting nanoscale structure, wood-derived cellulose nanofibrils (CNF) can be readily assembled into a wide variety of microstructures providing a substrate for novel redox-active materials. This thesis proposal outlines methods for making highly conductive, conjugated-polymer electrodes on cellulosic substrates both for enabling novel electrochromic devices and for developing a deeper understanding of how to control morphology and structure for enhanced electronic and ionic transport.
First, a simple method of generating highly conductive poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) films on cellulosic substrates is presented. These cellulose-based electrodes are then investigated for use in conjugated polymer electrochromic devices. Next, the capacitive properties of a soluble PEDOT analogue copolymer are discussed in order to highlight the key considerations for improving the performance of supercapacitor electrodes. A family of (3,4-propylenedioxythiophene) (ProDOT) monomers are then proposed in order to gain insight into how in situ oxidative polymerizations on cellulose surfaces can be controlled to boost electronic conductivity. These monomers will then be used for the preparation PProDOT films on anisotropic cellulose structures to study the impact of side chains and microstructure on mixed ionic and electronic transport. Finally, anisotropic cellulose structures will then be studied as optical waveguiding structures in the active layer of light emitting electrochemical cells.