The functional design of the smart electronic nose using polymer-film coated quartz resonator gas sensors, based on the solubility parameter of sensing membrane and gases, is carried out in order to develop the sensor with excellent selectivity and high sensitivity for harmful gases such as toluene, acetaldehyde and ammonia gases. The polymer-films such as propylene-butyl, poly-carbonate and acrylic-resin of which the solubility parameter almost coincide with that of toluene, acetaldehyde and ammonia gases, respectively, are chosen as a sensing membrane material coated on the quartz resonator. It is found that propylene-butyl-film coated quartz resonator gas senor exhibits a high sensitivity and an excellent selectivity for toluene and p-xylene gas, as it is expected from the functional design based on the solubility parameter. It is also found that poly-carbonate- film coated sensor and acrylic-resin-film coated sensor exhibit high sensitivity and excellent selectivity for acetaldehyde and ammonia, respectively, as it is also expected. The results strongly suggest that the solubility parameter is effective to functional design of the sensing membrane of quartz resonator gas sensors. The identification of gas kind is successfully possible by the principal component pattern recognition analysis of the transient response of the each sensor for gases.
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