  We derive an expression for the free energy of the blends of block copolymers
expressed as a functional of the density distribution of the monomer of each
block. The expression is a generalization of the Flory-Huggins-de Gennes theory
for homo polymer blends, and also a generalization of the Ohta-Kawasaki theory
for the melts of diblock copolymers. The expression can be used for any blends
of homopolymers and block copolymers of any topological structure. The
expression gives a fast and stable computational method to calculate the micro
and macro phase separation of the blends of homopolymers and block copolymers.

Soft Condensed Matter