Study On Preparation And Properties Of Conducting Polythiophene/Carbon Nanotube Composites

Conducting polymers (CPs) and their composites attract much research attention because of their great potential value in application. Polythiophene is one of the most important inherently conductive polymer materials. The high environment stability of both its doped and undoped states together with its structure versatility has led to multiple developments aiming at applications such as conductors, electrode materials and organic semiconductors. Some research works are conducted on polythiophene and polythiophene/carbon nanotube composites. The main content of this thesis is as follows:1. Effect of the Preparation Condition on the Properties of PolythiophenePolythiophene (PTh) was synthesized by direct oxidative polymerization of thiophene monomers under different conditions such as temperature, concentration, and reaction time. The structure and properties of the polymers were investigated. The result shows that the connection of the thiophene rings depends on the reactive conditions, which can induce the configuration of polythiophene. Moreover, configuration is directly related to conductivity, andα-αpolythiophene has a higher conductivity.2. Research on Preparation and Properties of PTh/MWNTs CompositesMulti-walled carbon nanotubes (MWNTs) were used as filler to prepare polythiophene (PTh) /MWNTs composites with high conductivity of 16.1 S/m. The characterization of the composites suggests that there is intensive interaction between MWNTs and PTh. Certainπ-πconjugated system is formed between delocalized electrons in MWNTs and theπ- electrons in the conjugated chain of PTh. The electrons transfer from MWNTs to PTh through thisπ-πsystem can prolong the effective conjugated chain of PTh and improve the conductibility of composites. 3. Conducting Mechanism and Model of PTh/MWNTs CompositesThe structure of polythiophene (PTh) / Multi-walled carbon nanotubes (MWNTs) composites were investigated, as well as the interaction between PTh and MWNTs. On one hand, the structure of PTh has an effective influence on the conductive properties of the composites. On the other hand, PTh is doped by MWNTs. There is certain interaction between MWNTs and PTh when the electrons transfer from MWNTs to PTh. MWNTs are combined with the doped PTh viaπ-πsystem to form individual conductive units which play a critical role in the conducting system. With the increase of the conductive units, a larger conducting system is formed by conductive unit connection and the conductivity of composites reaches the maximum.