Ionic Poly(3,4-ethylenedioxythiophene)s: From Synthetic Method Development to Applications Toward Sensory Materials and Functional Surface Coatings

• Main Authors: Hailemichael Ayalew Assen, 海麥克
• Other Authors: Yu, Hsiao-hua
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/ex2brj

博士 === 國立交通大學 === 永續化學科技國際研究生博士學位學程 === 107 === Abstract A vast number of researches reported so far indicated there are still plenty of voids for improvements in the syntheses and applications of organic electrically conducting polymers (ECP). The properties and applications of a material made of ECP can be tuned by modulating the side chain functional groups of the polymers used. In this thesis, poly(3,4-ethylenedioxythiophene) (PEDOT), which is one of the most explored conducting polymer family, has been used to demonstrate new synthetic method of water soluble anionic PEDOTs and to develop new PEDOT derivatives with different applications. Chapter one highlights up-to-date overview of syntheses methods and applications of functionalized PEDOTs reported in the past. Chapter two describes the synthetic procedures for monomers and polymers of which we employed throughout this study. Both anionic and cationic PEDOTs were designed and synthesized through chemical or electrochemical polymerization methods. A synthetic method with less steps and atom economical is today’s choice. In view of this, direct C-H arylation polymerization method was chosen and optimized to prepare water-soluble anionic PEDOTs with higher molecular weights, narrower polydispersities and higher yields (up to 99%) as discussed in Chapter three. Chapter four deals with horizontal conductivity shift profiles of PEDOTs which is a promising platform towards the development of conductivity based chemical or biological sensors. Here, carboxylic acid functionalized PEDOTs were electrodeposited on micro-electrodes and the effect of side chain length and polymer composition on conductivity curve profiles were studied in aqueous buffer of pH 4, 7 and 10. The best material to be integrated into microdevices for the development of conductivity based sensory materials has been identified with a horizontal conductivity shift of 269 mV. Incorporation of bioactive moiety on the side chain of conducting polymers gives myriad of uses in tailoring function of a material as described in Chapter five. We functionalized EDOT with a biguanide moiety and electrodeposited on ITO coated substrates to develop antibacterial and electrically conducting surface coatings. The results from antibacterial activities of PEDOT-biguanide coated surfaces show above 96% inhibition rate on Staphylococcus aureus bacteria. This is a promising result to explore more antimicrobial activities of the biguanide-functionalized PEDOT polymer on different bacterial specimen. We believe this will lead to develop alternative antibacterial and electrically conducting polymer surface coatings for domestic and biomedical devices.