Pressure induced mesophases in side-chain polymer liquid crystal revealed by neutron diffraction

We report here pressure studies on a side-chain liquid crystalline polymer which exhibits a reentrant nematic phase at atmospheric pressure. It reveal s that the two nematic transitions behave differently. The N-S-Ad transition is shifted towards, higher transition temperatures wh ereas the S-Ad-N-Re transition remains invariant with increasing pressure. In the smectic phase, a significant increase of the order parameter and of the correlation length of the smectic layers is observed. The results are o btained using a pressure cell specifically designed for neutron diffraction .