Fabrication and investigation of cellulose acetate-copper oxide nano-composite based humidity sensors

Cellulose acetate-copper oxide (CA-CuO) nano-composite based smart humidity sensors have been fabricated by using instrument-less novel technology, which is being introduced first time by our group. In this technology no major instrument is involved in the fabrication process. The composites are developed by solution and mechanical mixing techniques to fabricate film and pellet type sensors, respectively. The composition and surface morphologies are analyzed by field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS). Results of investigation show that the sensing range is from 0 to 90% relative humidity (RH) and sensing mechanism is based on change in resistance and capacitance with change in humidity. With change in humidity from 0 to 90% RH the resistance decreases by 1093 times, while the capacitance increases by 127 times. Average change in resistance and capacitance is up to 3.8 M Omega/%RH and 19.2 pF/%RH, respectively. The adsorption-desorption behavior and the consequences of measuring frequency have been discussed in detail. The fabricated sensors are attractive to develop reliable humidity meter for environmental monitoring and industrial applications. (C) 2016 Elsevier B.V. All rights reserved.