Propylene-oxide oligomers in heavy water (their molecular mass is ~500, and the concentration C varies from ~0.6 to 5.0 g/dL) and similar systems with C60 and C70 fullerenes and C60(OH)x fullerenols (x ~ 20), i.e., functionalized oligopropylene oxides, are studied via small-angle neutron scattering. The initial oligomers are found to create spherical micelles (~40 molecules) in the solution. It is ascertained that, in oligopropylene-oxide solutions, the C60, C70, and C60(OH)x derivatives (~1 wt % of fullerene relative to the oligomer) modify its molecular organization, acting as physical bonds whereby micelles are joined into large-scale linear, twisted, and branched chain superstructures.