Humidity Sensing Properties of Chitosan by Using Quartz Crystal Microbalance Method

Humidity adsorption kinetics of chitosan films was investigated by quartz crystal microbalance (QCM) technique. In this study, chitosan was synthesized from chitin by deacetylation process in 2.0% (v/v) acetic acid solution and then coated on QCM to measure humidity response. The Langmuir model was used to determine the adsorption rates and Gibbs free energy for various relative humidity between 11% and 94%. The average Gibbs free energy for adsorption was obtained as -12.93 kJ/mol. Our reproducible experimental results show that chitosan films are very sensitive to relative humidity changes at room temperature.