Effect of Ce(III)-Cu(II) 15-metallacrown-5 compounds on the dispersion of multi-walled carbon nanotubes in aqueous solutions: Toward surfactant-free applications

Metallacrowns (MC) possess unique structural and physicochemical properties leading to design of functional molecular materials. Herein we present the dispersing efficiency of Ce-Cu metallamacrocyclic complexes based on glycine- alanine- and phenylalanine hydroxamic acid with respect to multi-walled carbon nanotube (MWCNT) dispersion and exfoliation in water. The phenylalanine derivative MC was found to be a better dispersant than glycine and alanine derivatives MC. The aqueous phenylalanine derivative MC-MWCNT dispersion was quite stable over one month. This ability can be attributed to the efficient π-π interaction between the phenylalanine groups of the MC and the aromatic rings of MWCNTs. The formation of stable suspensions of MC-MWCNT could be a critical target in the development of practical applications of this valuable material.