Spectroscopic study of liquid crystals in confined volume

IR absorption spectra of nematic liquid crystal, pentylcyapobiphenyl (5CB), dispersed in porous glass and molecular sieves of types Si, Al-MCM-41 and Cu-Si, Al-MCM-41 (diameter of pores is about 40 Angstrom) have been investi gated in the region of fundamental and overtone vibrations. Mechanism of in teraction between a part of 5CB molecules and active centers of porous inte rface was estimated. In this case, enough strong interaction between the cy ano groups of 5CB and hydroxyl groups of the channel surface is realized. I t was also shown that another part of the 5CB molecule exists in the liquid crystal state and its amount depends on the size and nature of the pores. (C) 1999 Elsevier Science B.V. All rights reserved.