HUMIDITY-ELECTROCONDUCTIVE PROPERTIES OF PLASMA POLYMER-FILMS DERIVEDFROM PROPARGYL ALCOHOL MONOMER

A plastic plate on which a number of parallel electrodes were printed was coated with a plasma-polymer film derived from 2-propyn-1-ol (prop argyl alcohol, PA) or 60% water-containing PA (PW). The electroconduct ive properties of the films exposed to ambient air at various levels o f humidity were investigated. The electric current transported along t he films was proportional to the voltage applied to the electrodes; th e results were Ohmic irrespective of the given humidity or film thickn ess. The electric resistance of all the films had smaller values at hi gh humidity than at low humidity. The resistance changed its value fol lowing increase of the humidity. The film having a thickness of 10000 Angstrom seemed to have the best response characteristic for a wide ra nge of humidity levels. In comparison with the film derived from PA, t he other film from PW started to respond at somewhat lower humidity an d showed steeper change of the resistance at high humidity. The film h aving a thickness of 10000 Angstrom seemed to have the best response c haracteristic for a wide range of the humidity. Such a film might be a pplicable as a sensing device in a hygrometer. The response characteri stic could be modified to some extent by using different compositions of the water-containing PA.