Layer-by-layer assembled carbon nanotube films with molecule recognition function and lower capacitive background current

Multilayer films of multiwalled carbon nanotubes (MWCNTs) with molecule recognition function were assembled on glassy carbon (GC) electrode with lower capacitive background current by two steps: first, MWCNTs interacted with β-cyclodextrin (β-CD) with the aid of sonication to form β-CD-MWCNTs nanocomposite, then the β-CD-MWCNTs nanocomposite was assembled on GC electrode using layer-by-layer (LBL) method based on electrostatic interaction of positively charged biopolymer chitosan and negatively charged MWCNTs. The assembled β-CD-MWCNTs multilayer films were characterized by scanning electron microscopy (SEM) and cyclic voltammetry. The SEM indicated that the MWCNTs multilayer films with β-CD were somewhat more compact than that of the MWCNTs multilayer films without β-CD. The cyclic voltammetric results indicated that the assembled MWCNTs with β-CD on GC electrode exhibited lower capacitive background current than the assembled MWCNTs without β-CD. The MWCNTs multilayer films with β-CD were studied with respect to the electrocatalytic activity toward dopamine (DA). Compared with the MWCNTs multilayer films without β-CD, the MWCNTs multilayer films with β-CD possesses a much lower capacitive background current and higher electrocatalytic activity in phosphate buffer, which was ascribed to the relatively compact three-dimensional structure of the MWCNTs multilayer films with β-CD and the excellent molecule recognition function of β-CD.