The Phase Behavior of a Hydrogen Bonding Molecular Composite

The phase behavior of a blend containing poly(hydroxypropyl L-glutamine) (PHOPG), a rod-like polypeptide, and a coil-like random copolymer with 1.5% hydrogen bonding monomer is studied using light scattering, DSC, and optical microscopy. The results show that this system has an LCST. The phase behavior of this binary system is complicated by a glass transition and an ordering transition. Evidence is also observed of a possible change in phase demixing process, from nucleation and growth to spinodal decomposition, for a 50/50 blend with a change in temperature.