Study On Preparation And Performance Of Polyaniline/Carbon Nanotube Composites

Due to the easy availability, the ease of preparation, the low cost and special doping mechanism, polyaniline has become a focus in conducting polymers in recent years. Carbon nanotubes were the materials with one dimensional nanostructure. Its excellent electrical, optical and mechanical properties have made them very promising nanomaterials for many applications. The formation of polyaniline/carbon nanotube composites can be considered as a promising approach to obtain the materials in which the two elements have synergetic effects.Cationic surfactant cetyltrimethyl ammonium bromide(CTAB) was selected as dispersant to improve the dispersity of CNTs. In this article, PANI/CNTs composites were synthesized via chemical oxidative polymerization by using ammonium persulfate ((NH4)2S2O8) as oxidant and sulfosalicylic acid as dopant in aniline hydrochloride. Many factors affecting conductivity were investigated and optimized. And it was found that the conductivity of polyaniline was much higher when n(APS):n(An) =1, m(CNTs):m(AN)=0.07, n(SSA):n(An)=0.3, the dropwise time of APS was 2h, the reaction temperature was 0℃.The mophology, structure and performance of the products were observed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared spectra (FT-IR), thermogravimetric analysis (TGA) and UV-vis spectrometry. The formation mechanism of polyaniline/carbon nanotube composites were also investigated.Electrochemical methods was used to prepare polyaniline and polyaniline/carbon nanotube composites with citric acid as dopant in sulfuric acid solution. The influences of various factors to the conductivity were investigated. The result showed that the concentration of citric acid, sulfuric acid and other factors have great impacts on the conductivities and mophologies of products. The mophology, structure and the thermal stability of polyaniline prepared by electrochemical polymerization were observed by SEM. Electrochemical performance of the products were investigated and analyzed with electrochemical work station. It was proved that the redox property was better when the concentration of citric acid was lower. And compared with polyaniline, the impedance was lower and electrochemical properties better. .