Electrophoretic deposition of macroporous carbon nanotube assemblies for electrochemical applications

Electrophoretic deposition of macroporous assemblies of single-walled carbon nanotubes (SWCNTs) is described. The macroporous structure was created thanks to the presence of polystyrene (PS) beads which were co-deposited with the carbon nanotubes in a 60 V potential field. The ratio between the quantity of carbon nanotubes and polystyrene beads in the solution for deposition was found to be critical for the proper self-assembly of the composite film during electrophoretic deposition. The macroporous films have been characterized by scanning electron microscopy, atomic force microscopy and profilometry. The macroporosity was revealed after template removal (calcination of the PS beads). Access to the internal surface was assessed by electrochemical characterization using methylene green as a redox probe likely to adsorb on the SWCNT surface. Platinum nanoparticles and a sol–gel layer with encapsulated dehydrogenase and NAD⁺ cofactor have been deposited on the macroporous SWCNT electrodes in order to illustrate the use of the macropore texture for the detection of H₂O₂ and for biosensor applications, respectively.