Involvement of cyan and ester groups in surface interactions of aerosil-cyanophenyl alkyl benzoate systems with high silica density: Infrared investigations.

Composites prepared from aerosil A380 and liquid crystals (LCs) of 4-n-alkyl-4'-cyanophenyl benzoate type, with four to six carbon atoms in the alkyl chain were investigated by infrared spectroscopy. Their high silica content (of 2-7 g aerosil/1 g of LC) was given by thermogravimetric investigations and allows the observation of a rather thin LC layer on the silica particles. Several surface species onto the external surface of the grains were demonstrated.

Composites containing confined n-octyl-cyanobiphenyl: monomer and dimer species in the surface layer by in situ FTIR spectroscopy.

Confinement of 4-n-octyl-4'-cyanobiphenyl (8CB) to nanoporous molecular sieves with hexagonal structure of cylindrical pores (4.6nm diameter) is studied. Thermogravimetric investigations have indicated that the pores are completely filled.