LANGMUIR-BLODGETT-FILMS OF AN ASYMMETRICALLY SUBSTITUTED PHTHALOCYANINE - IMPROVED GAS-SENSING PROPERTIES

1,4-Bis(4-hydroxybutyl)-8,11,15,18,22,25-hexahexylphthalocyanine has been deposited as Langmuir-Blodgett (LB) films on to glass substrates bearing platinum-interdigitated electrode patterns. The prepared devices exhibit a useful room temperature response on exposure to NO2 gas in the occupational hygiene range. The magnitude of the response is proportional to the gas concentration and is also dependent upon the LB dipping direction relative to the axes of the electrodes. There is a lack of response to Cl2 and CO gases, exposure to which does not affect the response of the device on subsequent exposure to NO2 gas. The device can tolerate at least 65% relative humidity without detrimental effects.