Published online by Cambridge University Press: 08 November 2013
An extended version of self-consistent field (SCF) theory that was recently
introduced by the authors [Li et al., J. Chem. Phys.137, 024906, (2012)] is used to study the phase behavior of a
polymer blend with reversible crosslinks. The system consists of symmetric
AB diblock copolymers and homopolymers of type
A and B. We consider reversible crosslinks
that can form between the diblock copolymers with a crosslink strength
z and crosslink weights ωA and ωB for monomers of type A and B,
respectively. Crosslinks between homopolymers are disabled. We present a phase
diagram as a function of the A fraction of homopolymers $\phi _{\rm{\alpha }}^{{\rm{rel}}}$, the crosslink strength z, and the crosslink
asymmetry ∆ω = ωA − ωB. A hexagonal phase is found for suitably large
$\phi _{\rm{\alpha }}^{{\rm{rel}}}$, and suitably small z and
$\left| {\Delta {\rm{\omega }}} \right|$. Otherwise the system forms a lamellar phase. A deeper insight
into the phase behavior is gained from analyzing the free energy contributions
in the hexagonal and the lamellar phase with the help of the capabilities of the
extended SCF theory developed by us.