HUMIDITY SENSOR DURABLE AT HIGH HUMIDITY USING SIMULTANEOUSLY CROSS-LINKED AND QUATERNIZED POLY(CHLOROMETHYL STYRENE)

In order to prepare a resistive-type humidity sensor that is durable at high humidities or even in dewing, poly(chloromethyl styrene) is simultaneously crosslinked and quaternized (that is, a quaternary ammonium group is added to the polymer) by the reaction with N,N,N',N'-tetramethyl-1,6-hexanediamine on the surface of an alumina substrate on which a pair or gold electrodes is previously deposited. The sensor is durable even after soaking in water for two hours. The response time is shorter in samples with a higher degree of quaternization. An interpenetrating polymer network (IPN) film is also formed on a similar substrate using the crosslinked quaternized poly(chloromethyl styrene) and ethyleneglycol dimethylacrylate. A sensor based on the IPN film has a shorter response time than a sensor based on the crosslinked quaternized poly(chloromethyl styrene).