Micelle-encapsulated multi-wall carbon nanotubes with photosensitive copolymer and its application in the detection of dopamine

Photosensitive copolymer P(St- alt -MAn)- co -P(VM- alt -MAn) was synthesized and employed to disperse multi-wall carbon nanotubes (MWCNTs). It was found that copolymer could form micelles in aqueous solution and adsorb onto the surface of MWCNTs to produce micelle-encapsulated MWCNTs (e-MWCNTs) by in situ photo crosslinking after irradiation with ultraviolet light and a stable suspension of e-MWCNTs in aqueous solution was obtained. When deposited onto polyaniline (PANI)-modified glassy carbon electrodes, a thin film of e-MWCNTs composite was obtained and the performance of the e-MWCNTs/PANI electrode toward dopamine was then evaluated. The experimental results suggest that the hybrid film modified electrode exhibits a dramatic electrocatalytic effect on the oxidation of dopamine (DA), as evidenced by a marked enhancement of the current response. A series of CVs was obtained by modified glassy-carbon electrodes with different size of micelles was also researched. The result shows that the peak current increased with the increasing size of micelles. A linear calibration plot was obtained in a wide range of 1.0 × 10 −7 –1.0 × 10 −3  M and the detection limit was 5.0 × 10 −8  M. In addition, the interference from ascorbic acid (AA) was effectively suppressed due to the presence of the negatively charged carboxylate groups of copolymer on the outside of MWCNTs which repels AA anions and provides a transport channel only for DA cations.