Langmuir, Vol.10, No.3, 905-911, 1994
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 showed Z-type vertical deposition. X-ray diffraction results show that the 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 hydrophilic chain ends, utilizing its low hydrophilicity. X-ray diffraction and pyroelectric measurements suggest that a polar film was constructed with nitrobiphenyl oriented in the same direction. The pyroelectric coefficient of the alternating-layer film was measured to be 1.7 x 10(-10) C cm-2 K-1.
Keywords:LIQUID-CRYSTALLINE POLYMERS;CONTACT-ANGLE HYSTERESIS;MULTILAYER FILMS;X-TYPE;SUPERLATTICES;AMPHIPHILES;MONOLAYERS;MOLECULES;BEHAVIOR