HUMIDITY SENSING PROPERTIES OF PLASTICIZED CA-NH4BF4-PEG600 THIN FILMS

Abstract

The fabrication of resistive-type humidity sensor based on CA-NH₄BF₄-PEG₆₀₀ plasticized polymer electrolytes film was prepared by using dip-coating method on a glass substrate. The electrical properties of the film are examined as a function of relative humidity (R.H) to clarify its potential as a humidity sensor. The sensor well responded towards humidity showing that the resistance drops with the increase in relative humidity, thus confirmed that the resistive-sensor exhibits humidity–sensitive property. The sensor element has also been characterized in terms of the effect of applied frequency in the range of 100 Hz to 10 kHz. The values of resistance show the decrement with increasing in frequency. Apart from frequency dependence, the measurement has also been carried out at different temperature elevation between 30°C and 50°C. The value of resistance decreases with increasing temperature as a result of ion mobility enhancement at higher temperature. The temperature dependence of resistance obeys Arrhenius law and the activation energy decreases with increasing in relative humidity. These entire behaviours can be explained by the conduction process occurred in CA-NH₄BF₄-PEG₆₀₀ films.