STRUCTURAL MEMORY EFFECT IN LIQUID-CRYSTAL PHASES STABILIZED BY SILICA PARTICLE AGGREGATES

A SANS study revealed the orientational stabilisation of the smectic s tructure by non-mesogenic polymer networks dispersed in a liquid cryst al matrix. In the present experiment, hydrophobic silica particles wer e dispersed in liquid crystal 8CB. The Bragg reflections from smectic layers show that the alignment of the layers is perfect if the system is cooled down in a magnetic field. After annealing without magnetic f ield and cooling down to smectic A phase, the previous alignment of th e liquid crystal is recovered. Temperature and concentration dependenc e of the effect has been analysed by recording the diffraction pattern from smectic layers. (C) 1998 Elsevier Science B.V. All rights reserv ed.