Abstract
We present a generalized theory for studying phase separation in polymer blends
containing dipoles on their backbone. The theory is used to construct co-existence
curves and study the effects of dipolar interactions on interfacial tension for a planar
interface between the coexisting phases. It is shown that mismatch in monomeric
dipole moments leads to destabilization of homogeneous phase. Corrections to the
Flory-Huggins phase diagram are predicted using the theory. Furthermore, it is found
that interfacial tension increases with an increase in the mismatch. Density profiles
and interfacial tensions are constructed for diffuse and sharp polymer-polymer interfaces
by extending Cahn-Hilliard and Helfand-Tagami-Sapse’s treatment, respectively.
Correlating dipole moments with the dielectric constant of pure phases, it
is demonstrated that effects of mismatch between the dipole moments of the two
monomers is equivalent to the dielectric mismatch between the polymers.
