Application of dilational surface
rheology, surface tensiometry,
ellipsometry, Brewster angle, and transmission electron and atomic
force microscopies allowed the estimation of the structure of the
adsorption layer of a fullerenol with a large number of hydroxyl groups,
C60(OH)
X
(X = 30 ± 2). The surface properties of fullerenol solutions proved
to be similar to the properties of dispersions of solid nanoparticles
and differ from those of the solutions of conventional surfactants
and amphiphilic macromolecules. Although the surface activity of fullerenol
is not high, it forms adsorption layers of high surface elasticity
up to 170 mN/m. The layer consists of small interconnected surface
aggregates with the thickness corresponding to two–three layers
of fullerenol molecules. The aggregates are not adsorbed from the
bulk phase but formed at the interface. The adsorption kinetics is
controlled by an electrostatic adsorption barrier at the interface.