Direct Electrochemical Generation Of Polyaniline Microrings And In-Situ Conductivity Measurement Of Conducting Polymer

Conducting polyaniline has many potential applications in fabricating rechargeablebattery, emitting diode and biosensors due to its controllable conductivity and opticalactivities. With the extensive research and application of nanomaterials, it is expected tosynthesize micro/nano-structured conducting polymer with both advantages of nanomaterialsand organic conductors. In this thesis, a direct chemical method was applied to preparemicrorings of conducting polymer. Meanwhile, some basic study was focus on in-situconductivity measurement of conducting polymer using a home-made in situ Electrochemicalconductometer (ECC). Based on the resistance changes, a simple mathematical model wasdeduced to investigate the kinetics of conductivity change.1. Self-doped polyaniline (SPANI) microrings were generated on indium tin oxide (ITO)substrates via an electrochemical polymerization process. FE-SEMs showed typicalmicro-ring width of ca. 100nm, with ring diameter varying from several to dozens ofmicrometers, depending on deferent current density and time profiles during polymerization.Morphological observations are interpreted in the context of a gas-bubble-templatemechanism of micro-ring formation. In confirmatory experiments, where reaction solutionswere degassed with nitrogen throughout electropolymerization, micro-belts were observedinstead. These findings demonstrate that the potential for precise control ofconducting-polymer microstructure through controlling simple reaction variables andelectrode surface properties.2. A two-band electrode with new insulate material as very small gap with a newlydeveloped electric circuit was used for in situ conductivity measurement of electrochemicallypolymerized conducting polymer. The typical cyclic voltammetry and change of resistancewere measured spontaneously. Furthermore, the first order reaction kinetics was alsoinvestigated in different systems base on the changes of resistance to study the aging processof conducting polymer holding a series of applied potential. At last, the camphorsulfonic acid(CSA) doped polyaniline was also investigated in the experiment to compare the effect on theconductivity changes.