Influence of <scp><i>Eichhornia crassipes</i></scp>‐Derived Cellulose Nanocrystals and <scp>ZnO</scp> Nanoparticles on Moisture and Biological Properties of <scp>PVA</scp>/<scp>PVP</scp> Nanocomposites for Smart Agriculture

Abstract

ABSTRACT Humidity surveillance is a requirement for several applications, including medical, pharmaceutical, food storage, and agriculture. This work describes the fabrication of humidity sensors from cellulose nanocrystals (CNCs) and ZnO nanoparticles (ZnO NPs) integrated inside a polyvinyl alcohol (PVA)/polyvinylpyrrolidone (PVP) blend created by a solvent‐casting method. A 10 wt.% of CNCs were used with variable quantities of ZnO NPs (i.e., 3, 7, and 15 wt.%) to prepare PVA/PVP nanocomposite films. The films were characterized using X‐ray diffraction, Raman spectroscopy, as well as mechanical, thermal, and antibacterial properties. In all cases, ZnO NPs improved morphology, thermal stability, and antibacterial properties. The tensile properties were slightly reduced compared to unfilled matrix (~33 MPa), but their tensile stress values were still higher than filled film‐based CNCs (P/CNC, 22.60 MPa). Whereas the outcomes from the antibacterial experiment illustrated that the halos of inhibition were observed for film‐based ZnO NPs with different diameters ranging from 3 to 16 nm, depending on the microbe and the film type. These results indicate that these films could be used in active packaging and the biological area because these materials prolong shelf life. Correspondingly, a P/CNC moisture sensor possessed higher sensitivity with low hysteresis over a wide range of relative humidity (11%–97%) and at 300 Hz.