Ag‐nanocomposite based on carboxymethylcellulose for humidity detection: Green synthesis and sensing performances

Abstract

A novel highly sensitive Ag-nanocomposite for humidity detection has been successfully prepared. Initially, cellulose isolated from Tunisian palm date petiole was converted to carboxymethyl cellulose (CMC) as biomatrix under heterogeneous conditions. The synthesized product was thoroughly characterized by means of FT-IR spectroscopy, viscosity analysis, and high performance size exclusion chromatography multiangle laser light scattering. CMC was used as reducing and stabilizing agent to prepare CMCstabilized silver nanoparticles via a rapid green method. The bioreduction of silver ions under different experimental conditions, including Ag 1 concentration and pH, was investigated. Optimal experimental conditions provided a long-term stable colloidal suspension and well-dispersed spherical shape Ag NPs with a size ranging from 13 to 28 nm. Ag-nanocomposite coated quartz microbalance crystal was used as sensitive layer for humidity detection. A comparative study showed that the immobilized metallic nanostructures greatly reduced changes in visco-elastic properties, increased surface area as well as surface local charge density of the CMC. Consequently, sensor performances were greatly enhanced: better stability even at higher relative humidity (RH), good reproducibility and linearity (11-98% RH), low hysteresis characteristics, and rapid response and recovery times (14 and 6 s, respectively) were obtained.