Wolf, B.A.

"Binary Interaction Parameters, Ternary Systems: Realistic Modeling of Liquid/Liquid Phase Separation"

Macromolecular Theory and Simulation* ***2009**, *18*,
30-41.

**Abstract: **The present modeling considers two specific features
of polymers explicitly: Chain connectivity and their ability to respond to changes
in the molecular environment by conformational reorientation. So far this approach
has been applied to polymer solutions in single solvents. Here it is generalized
to arbitrary molecular weights of the components and the number of parameters
is reduced to two per binary system. The calculation of the Gibbs energies of
the ternary mixtures accounts for the composition dependencies of the binary
interaction parameters. The following phenomena are reproduced realistically
for polymer solutions in a mixed solvent and for solutions of two polymers in
a common solvent: Simplicity (gradual transitions between the miscibility gaps
of the binaries), co-solvency (complete miscibility of one component with mixtures
of the other two components only), and co-non-solvency (islands of immiscibility
despite totally miscible binaries). The results nourish the hope that the new
approach is capable of modeling phase diagrams for ternary systems by means
of binary interaction parameters, without the necessity to introduce ternary
ones.

preprint number: 293