  We develop two new amphiphilic molecules that are shown to act as efficient
surfactants for carbon nanotubes in non-polar organic solvents. The active
conjugated groups, which are highly attracted to graphene nanotube surface, are
based on pyrene and porphyrin. We show that relatively short (C18) carbon tails
are insufficient to provide stabilization. As our ultimate aim is to disperse
and stabilize nanotubes in siloxane matrix (polymer and crosslinked elastomer),
both surfactant molecules were made with long siloxane tails to facilitate
solubility and steric stabilization. We show that pyrene-siloxane surfactant is
very effective in dispersing multi-wall nanotubes, while the porphyrin-siloxane
is making single-wall nanotubes soluble, both in petroleum ether and in
siloxane matrix.
