Cross-linked multilayer composite films and microcapsules embedded carbon nanotubes

• LbL assembly of CNTs and PAH is carried out on planar substrates and spherical templates.
• PAH is cross-linked with glutaraldehyde to form network films and shells embedded CNTs.
• Cross-linking leads to significantly enhanced stability of the multilayers.
• Removal of polystyrene cores results in hollow CNTs microcapsules.

The layer-by-layer (LbL) assembly of multi-walled carbon nanotubes (MWNTs) and poly(allylamine hydrochloride) (PAH) is carried out via the electrostatic interactions on planar substrates and polystyrene (PS) microsphere templates. The successful planar and spherical growth of PAH/MWNTs multilayer could be investigated by scanning electron microscopy (SEM) and/or UV–vis spectrophotometry. Subsequent cross-linking of the PAH through Schiff-base reaction with glutaraldehyde leads to PAH network films and shells embedded MWNTs, which show significantly enhanced stability against solvents under sonication. For the (PAH/MWNTs)/PS core–shell microsphere composites upon cross-linking, the PS cores could be removed by dissolution and the stabilized PAH/MWNTs shells transform to hollow microcapsules.