Surface Immobilization And Modification On Gold Electrode Using Carbon Nanotubes

In this paper, carbon nanotubes were immobilizated on the surface of gold electrode oriently. The surface was then modificated by conductive polymer further and finally came into a rough hairlike one with one-dimension nanowire structure.Single-walled carbon nanotubes (SWNTs) were used in this research, different parameters(time, temperature, treatment methods, etc.) were discussed, so as to determine their effects on purification, cutting and debundling of SWNTs and choose the optimal experimental conditions(mixed concentrated acid, low temperature and ultrasonication) to prepare a stable suspension in a short time. Sodium dodecylbenzene sulfonate (SDBS) was added to enhance the stabilization of the aqueous suspension. A surface condensation reaction between amino and carboxylic groups was then performed by immersing an amino self-assembled monolayer (SAM)-modified gold eletrode into the aqueous suspension of SWNTs with the aid of N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC.HC1) and sulfo-N-hydroxysuccinimide (s-NHS), thereafter SWNTs has been immobilized on gold oriently. Poly(3,4-ethylenedioxythiophene) (PEDOT) films were prepared on the SWNT-immoblized electrode by potentiostatic electropolymerization from EDOT aqueous solution, with p-toluene sulfonic acid sodium salt (TsONa) as the supporting electrolytes.Field Emission-scanning electron microscopy (FSEM), transmission electron microscopy (TEM), infrared spectrometry and raman spectrometry were used to characterize the structure and modality of SWNTs before and after acid treatment. Raman spectrometry could also testify the immobilization of SWNTs on gold while atomic force microscopy (AFM) showed the perpendicular standing state of SWNTs on gold surface. Scanning electron microscopy (SEM) was used for observing the rough surface after polymerization of EDOT on modified gold andthe results of cyclic voltammetry (CV) showed that all the modified electrodeshave remarkable improvements in electrochemistry properties.