  Diblock copolymers blended with homopolymer may self-assemble into spherical,
cylindrical or lamellar aggregates. Transitions between these structures may be
driven by varying the homopolymer molecular weight or the molecular weight or
composition of the diblock. Using self-consistent field theory (SCFT), we
reproduce these effects. Our results are compared with X-ray scattering and
transmission electron microscopy measurements by Kinning, Winey and Thomas and
good agreement is found, although the tendency to form cylindrical and lamellar
structures is sometimes overestimated due to our neglect of edge effects due to
the finite size of these aggregates. Our results demonstrate that
self-consistent field theory can provide detailed information on the
self-assembly of isolated block copolymer aggregates.
