Novel methodology of chitosan- salicylaldehyde polymers: synthesis, characterization, and application in NH3 sensing

Abstract

Chitosan (Ch)-salicylaldehyde (Sal) polymer derivatives were formed via chitosan modification. These polymers were synthesized through inclusion with β-cylcodextrine (β-CD) and doping with zinc oxide nanoparticles (ZnO NPs) to give pseudopolyrotaxane and Chs-Sal/ZnO NPs composite, respectively. Additionally, the complicated polymer (Chs-Sal/ β-CD/ZnO NPs) was prepared via insertion of generated composite (Chs-Sal/ZnO NPs) through β-cyclodextrin ring. The structural and morphological characterizations of the synthesized derivatives were confirmed by utilizing FTIR, XRD and SEM, respectively. Also, the optical properties and thermal gravimetric analysis (TGA) of the synthesized polymers were explored. The obtained results confirmed that using β-CD or ZnO NPs for modification of polymer (chs-sal) dramatically enhanced thermal stability and optical features of the synthesized polymers. Investigations on the NH3-sensing properties of Chs-Sal/β-CD/ZnO NPs composite were carried out at concentrations down to 10 ppm at room temperature (RT) and indicated that modification by β-CD and doping with ZnO NPs effectively improves the NH3-sensing response of Chs-Sal and exhibited good selectivity and good response-recovery time at RT.