Abstract: Chitosan(CS)/CdS nanocomposite films have been prepared via in situ generation of CdS nanoparticles. The factors affecting the hydrothermal stability and the fluorescence properties of the films have been studied. Furthermore, the sensing properties of the nanocomposite films to pyridine in water have been systematically investigated. SEM observation showed that the sizes of the CdS particles are around 70 nm, and the particles are evenly doped within the CS films. The positions of the fluorescence emission of the nanocomposite films indicate that the sizes of the real fluorescing CdS particles are less than 20 nm, suggesting that the CdS particles observed via SEM may be aggregates of small CdS particles, and the small particles may be separated by the organics. It has been found that the fluorescence emission of the nanocomposite films is very sensitive to the presence of pyridine, and microamount of pyridine makes the emission increase dramatically. The emission is hardly affected by common ions in water, except copper and iodide ions. It is predicted that the films may be developed into an excellent sensing films for pyridine in water.

Key words: CdS, Chitosan, Fluorescence, Nanocomposite materials, Thin film