Authors:Elena Burakova, Alexandr Melezhyk, Alyona Gerasimova, Evgeny Galunin, Nariman Memetov, and Alexey Tkachev
In the present research, phenol-formaldehyde resins were used instead of common surfactants for dispersing carbon nanotubes and graphene nanoplatelets in order to develop new composite materials. The use of such resins makes it possible to increase the concentration of nanoparticles in solution by approximately two orders of magnitude. The presence of reactive groups on the surface of the phenol-formaldehyde-resin-modified carbonnanotubes and graphene nanoplatelets promotes synthesis of a variety of composites. According to the experiments performed herein, the modification of the nanomaterials with the phenol-formaldehyde resin significantly improves their compatibility and provides good water-solubility. While dispersing in water, the aggregates of the carbon nanotubes disappear, giving rise to an ordered structure. Besides, they form stable colloidal solutions at slightly alkaline pH values, but coagulate when decreasing the pH. This effect allows for self-assembly of carbon and composite nanostructures from nanoparticles in solution due to pH adjustment. This enables easy synthesis of hybrid composite materials based on carbon nanotubes, graphene nanoplatelets and phenol-formaldehyde resins.