Morphology control in polyamide/ionomer blends

Blends of lightly sulfonated polystyrene and poly(N,N'-dimethylethylene sebacamide) (Li-SPS/mPA) are miscible as a result of strong ion-amide complexation. The blends exhibit LCST phase behavior. Phase separation may be thermally induced and is thermodynamically reversible. The phase separation kinetics that occur following a temperature-jump deep into the spinodal region of die phase diagram deviate from conventional Cahn-Hilliard theory and tile phase separation process stalls after a couple of hours, essentially pinning the structure at that point. The extent of phase-separation that occurs before pinning is temperature-dependent, and the structure Pinning mechanism may represent an effective way to control the development of a two-phase morphology in a polymer blend.