NONCENTROSYMMETRIC LANGMUIR-BLODGETT-FILMS CONTAINING NITROBIPHENYL GROUPS

The monolayer formation of two nitrobiphenyl-containing compounds was facilitated by mixing molecules that have similar structures. Transfer behavior of the monolayers to microscope slides made hydrophobic was examined by vertical and horizontal deposition. All the monolayers sho wed Z-type vertical deposition. X-ray diffraction results show that th e multilayer structure is Y-type, irrespective of the deposition type. However an alternating-layer method of deposition was developed, such that nitrobiphenyl can be located either on the hydrophobic or the hy drophilic chain ends, utilizing its low hydrophilicity. X-ray diffract ion and pyroelectric measurements suggest that a polar film was constr ucted with nitrobiphenyl oriented in the same direction. The pyroelect ric coefficient of the alternating-layer film was measured to be 1.7 x 10(-10) C cm-2 K-1.