Syntheses And Properties Of Several Derivatives Of Polythiophene

The derivatives of polythiophene usually have desirable electrochemical activity, environmental stability and easy processibility, which provide potential applications in various fields as electronics, optics, biology, etc. In present dissertation, we have synthesized three new polythiophene derivatives via electrochemical or chemical methods and characterized the structures and properties of the obtained polymers.1. 3-phenylthiophene was electropolymerized in pure boron trifluoride diethyl etherate (BFEE) and free standing films of poly(3-phenylthiophene) (P3PhT) were yielded. This work has enriched the researches on electrosynthses of conducting polymers in the electrolyte of BFEE. The oxidation potential of the monomer was lower than that measured in a neutral medium of acetonitrile and thus the quality of the polymer was improved, which demonstrated good electroactivity, chemical and environmental stability. A typical film of P3PhT has a tensile strength as high as 32-40 MPa and a conductivity of 0.01 Siemens per centimeter. Raman spectral results demonstrated that the doping level of P3PhT films increased with the increase of deposited charge density during the electrochemical growth process.2. 2-Phenylthiophene has been electrochemically polymerized in BFEE and in a composite electrolyte of BFEE and trifluoacetic acid (TFA). The addition of certain amount of TFA into BFEE lowered the oxide potential of the monomer and accelerated the polymerization. A judicious choice of TFA concentration could increase the current efficiency of the electrosynthesis to 70%. The structure of the polymer has been examined by infrared and Raman spectroscopies, which showed evidence of ?,??-coupling in the polymer. The dedoped polymer can be dissolved in some common organic solvents and fluorescent spectral studies indicated the polymer is a blue-green light emitter. 3. A new type of functionalized thiophene, 3-(10-mercaptodecyl)thiophene (MDT), was synthesized from 1,10-dibromodecane as the starting reagent. In dichloromethane-water liquid-liquid system, MDT reacted with tetrachloroaurate to yield monolayer protected gold nanoparticles (MPCs). Ferric chloride was added to a dichloromethane dispersion of MPCs to polymerize the thiophene moieties and the core-shell structure of gold nanoparticle/poly(3-(10-mercaptodecyl)thiophene) was yielded. High resolution transmission electron microscope, infrared and Raman spectroscopies were utilized to characterize the structure. In this reaction, tetrabutyl ammonium-dichloromethane system was used for extraction, which substituted traditional tetraoctyl ammonium-toluene system used in previous literatures and improved the reaction economically. Meanwhile, the facile and convenient approach developed here for the incorporation of gold nanoparticles can be also applied to other nanoparticles such as Pt, CdSe, etc.