ORIENTATIONAL ORDER IN LIQUID-CRYSTAL SOLUTIONS OF POLYHEXYLISOCYANATE .1. INFRARED DICHROISM

The concentration and molecular weight dependence of the order parameter was measured for liquid crystalline solutions of the semiflexible, extended chain polymer polyhexylisocyanate in chloroform and toluene. Order parameters were determined from the infrared dichroism of the stretching vibration of the C-N bond in the helical polymer backbone. Results are compared with predictions of a version of the Onsager theory for wormlike chains, extended to higher solute densities by the use of a decoupling approximation.