P2EC.18 - Humidity sensing effect of doped metal salts based on polyvinyl alcohol complex materials

17th International Meeting on Chemical Sensors - IMCS 2018
2018-07-15 - 2018-07-19
Vienna, Austria
P-2 - Electrochemical Sensors
H. Cho, K. Lee, D. Lee, S. Han - Shinwoo Electronics Co., LTD., Gyeonggi-do (Republic of Korea)
732 - 733


Organic polyelectrolytes have suggested as humidity sensing materials, however they lack in durability as they are easily attacked by moistures. Polyvinyl alcohol(PVA) is a common hydrophilic polymer having an –OH group at an alternate carbon in its back-bone but with changing humidity an impedance response is low. The simple PVA humidity sensor lacks durability and also shows high impedance. To overcome this problem, cross-linking of polyvinyl alcohol was done with 4-styrene sulfonate in presence of metal ions. The humidity sensor materials were obtained when polyvinyl alcohol was cross-linked with 4-styrene sulfonate in presence of some ions at a temperature of 140°C for about 1 hour and when polyvinyl alcohol, 4-styrene sulfonate (sodium salt hydrate) and metal ions were taken in a weight ratio of 10:3:4 respectively. The polymeric mixture of the three materials made in water was printed on an SiO2/Si substrate prefabricated with interdigitated gold electrodes and was cured at a temperature of 140°C. The results demonstrate that the logarithm of the resistance decreased linearly with increase in %RH in a range of 10-90% RH. Other factors viz. stability, sensitivity and response time for the fabricated sensor were also determined.