Preparation of polyaniline/multiwalled carbon nanotube composite by novel electrophoretic route

A nano-structured composite film comprising of emeraldine salt (ES) and carboxyl group functionalized multiwalled carbon nanotubes (MWCNT-c) has been electrophoretically prepared from their colloidal suspension on an indium–tin–oxide (ITO) coated glass plate. This nano-structured composite film (ES/MWCNT-c) has been characterized using atomic force microscopy (AFM), ultraviolet–visible (UV–visible) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The AFM studies reveal porous morphology with uniformly distributed MWCNT-c in this composite film. The SEM and TEM investigations reveal wrapping of MWCNT-c with the chains of ES. UV–visible and FT-IR investigations show the formation of MWCNT-c doped composite at the molecular level. The results of the CV and EIS studies indicate enhanced electrochemical and charge transfer behavior of the composite. The application of ES/MWCNT-c/ITO electrode to biosensor for cholesterol indicates short response time (10 s) and high sensitivity (6800 nA mM−1).