CHAIN-LENGTH DEPENDENCE OF MOLECULAR ORDERING IN LB FILMS OF AMPHOTROPIC PHTHALOCYANINES

Langmuir-Blodgett films of two amphiphilic liquid crystalline phthaloc yanines, differing in the lengths of their substituent chains, have be en prepared on various substrates. Monolayers were obtained at an air: water interface. pi-A isotherms reveal very satisfactory stability of the compressed monolayer in which the rings of the macrocycles are app roximately perpendicular to the water surface. The compressed monolaye rs were transferred Y-type by vertical motion of the substrate. Polari zed visible region spectrophotometry, transmission infrared spectrosco py and reflection absorption infrared spectroscopy reveal ordering wit hin the films. Two distinct types of molecular packing are observed de pending on the length of the hydrophobic chain. Both undergo significa nt reorganization at elevated temperature.