Agglomeration of silica nanoparticles in filled nematic liquid crystals

The large memory effect of about 95 per cent was achieved in nematic liquid crystal filled with big hydrophilic silica nanoparticles (d=40 nm) and low surface area 50+/-15 m(2)/g. We have measured the temperature dependence o f transmittance and heat flow of this system. We have found a small but cle arly positive shift of the nematic liquid crystal-isotropic liquid transiti on temperature with the increase of concentration of nanoparticles. The mai n origin of the large memory effect is the orientational influence of surfa ce of the silica nanoparticle agglomerates. Agglomeration of nanoparticles is induced by orientational elastic forces of liquid crystal. This effect c an be used to form regular or complex microstructures from silica nanoparti cles. Applications of such a mixture also include 2-dimensional pressure im aging.