GAS SORPTION TO PLASMA-POLYMERIZED COPPER PHTHALOCYANINE FILM FORMED ON A PIEZOELECTRIC CRYSTAL

Copper phthalocyanine was plasma-polymerized on piezoelectric quartz crystals. The film formed was very stable and resistant to chemical and physical treatment. Various spectroscopic data suggested that the essential properties of phthalocyanine remained after the polymerization. A variety of organic chemicals were examined to measure the sorption to the film from the gas phase (in the presence of air). Adsorption of gases to the film decreased the oscillating frequency. Sensitivity was defined as the frequency decrease per 1 part per million (ppm) of a certain gas, and the values ranged from 670 to 0.001 Hz/ppm. Chemicals showing high affinity are plane molecules with conjugate double bonds and some polar substituting groups or are higher alcohols, such as vanillin, benzoic acid, aniline, nitrobenzene, phenol, n-octyl alcohol, 1-nonanol, n -decyl alcohol, benzyl alcohol, DL-cam-phor, β-ionone, naphthalene, and anthracene. The film on the piezoelectric crystals was proved to have a life as long as 60 days. The sensitivity to various chemicals was dependent on a central metal of phthalocyanine. © 1990, American Chemical Society. All rights reserved.