Sensing element for measuring moisture, especially for measuring high values of relative humidity up to 90 percent RH even at temperature values above 80 degC and process for its production

摘要

The present invention relates to an enhancement of a known sensing element for measuring moisture comprising a system of interdigital conductive electrodes varying upon change of environment humidity their electric conductance and provided with at least one thin sensor layer of organic material, phthalocyanine of the general formula I, wherein M represents Hi2, Zn, HOAl, Ni, Cu; and Ri1, Ri2, Ri3, Ri4 denote independently on each other -H, -SOi3H, -SOi3Na, -SOi3K, -SOi3Li, -SOi3NHi4 and -SOi2NHi2. The sensor layer according to the present invention is a sandwich type layer, whereby a second layer formed by at least one phthalocyanine sulfonamide derivative of the general formula II, in which M represents Hi2, Zn, HOAl, Ni, Cu; and Ri1, Ri2, Ri3 and Ri4 denote independently on each other -H, -SOi3H, -SOi3Na, -SOi3K, -SOi3Li, -SOi3NHi4, -SOi2NHi2, -SOi2NHCHi2CHi2CHi2N(Ci2Hi5)i2, -SOi2NHCHi2CHi2CHi2N(CHi3)i2, -SOi2NHCHi2CHi2NHCHi2CHi2OH, -SOi2NHCHi2CHi2CHi2CHi2CHi2CHi2CHi2CHi3, -SOi2NH(CHi2)i17CHi3 is applied to the first layer; in a mixture with polystyrene or the polystyrene alone. The layers are applied as a solution or suspension in polar or non-polar solvent, or in a binder based on organic materials, wherein the solvent or binder evaporates. The sensing element for measuring humidity of the present invention exhibits a quick and well reproducible response, high sensitivity and a long-term stability in the range of 20 to 90 percent of relative humidity at temperature values ranging from 30 to 85 degC.