PYROELECTRICITY OF NONCENTROSYMMETRIC LANGMUIR-BLODGETT-FILMS OF PHENYLPYRAZINE DERIVATIVES

Pyroelectricity of alternating Langmuir-Blodgett (LB) films consisting of phenylpyrazine derivatives and stearic acid was measured by the st atic method at various temperatures. It was found that the LB films co nsisting of a compound with highly conjugated pi-electron system showe d large pyroelectricity which was greatly dependent on the temperature of the sample films. The sign of the pyroelectric coefficients change d at a temperature characteristic of the films. In the high-temperatur e range, a dull pyroelectric response was observed. The pyroelectricit y of LB films with various ion complexes was also examined. The films of polyion complex which had more spatial freedom showed larger pyroel ectricity. However, an extremely sparse molecular packing gave a low d egree of molecular orientation in the film resulting in small pyroelec tricity.