Jin-Hyo Park

Humidity Sensor Using Chemically Synthesized Poly(1,5‐diaminonaphthalene) Doped with Carbon

The chemically synthesized poly( 1,5-diaminonaphthalene) (DAN) dopec with carbon was applied to a humidity sensor. The polymer was characterized using Fourier tranform infrared, ultraviolet-visible spectrometry, and cyclic voltammetry. The composite polymer film was prepared by mixing the poly(1,5-DAN) powder with acetylene carbon black in various ratios and 6.0 wt % polyvinylidene fluoride in N-methylpyrrolidone. The composite polymer sensor was examined and applied to the amperometric and the resistance-type humidity sensor employing chronoamperometry and impedance spectrometry. The relative humidity was controlled using the standard saturated salt solutions at 20 ± 0.1°C. Under optimized experimental conditions, the calibration plot for the 15:1 composition sensor showed a straight line over the entire measured range of percent relative humidity (RH) without hysteresis. The overall sensitivity was calculated as S = [R(93% RH) - R(12% RH)]/R(93% RH). The current drift was less than ±1% for the lower humidity.