INDUCTION OF THE SMECTIC PHASE IN BLENDS OF SIDE-CHAIN LIQUID-CRYSTALLINE POLYMERS BY ELECTRON DONOR-ACCEPTOR INTERACTIONS

Miscible polymer blends were prepared from poly[4[[6-(methacryloyloxy)hexyl]oxy]-N-[(9-methyl-2-carbazolyl)methylene]aniline] and poly[4-[[6-(methacryloyloxy)hexyl]oxy]-N-(4'-nitrobenzylidene)- aniline]. These polymer blends exhibited homogeneous smectic phases when the proportion of the mesogenic carbazolyl unit was in the range of 0.3-0.6, though the smectic phase did not appear in both homopolymers. The 1:1 (mole ratio) polymer blend showed a smectic phase from 69 to 190 degrees C. A similar tendency on the thermal behavior was observed for the binary mixtures of both low-molecular-weight compounds containing the same electron donor and acceptor mesogens. On the other hand, the polymer blend composed of both electron-donating side-chain liquid-crystalline polymers containing carbazolyl and methoxyphenyl groups showed a phase separation. In addition, the thermal behaviors were examined on a blend of an electron-donating polymer with an electron-accepting compound. The miscibility in the polymer blends was caused by intermolecular electron donor-acceptor interactions which made the blends orient to organize a smectic phase.