壳聚糖-CdS复合膜制备及其对吡啶的传感特性

利用壳聚糖（CS）易于成膜的特点，模拟生物矿化，在有机物调制下通过异相成核生长制备了CS/CdS纳米颗粒复合膜.研究了成膜条件对膜的水热稳定性和发光性能的影响，以及CS/CdS纳米颗粒复合膜对水体中吡啶的响应特性.扫描电镜分析表明CS/CdS纳米颗粒复合膜均匀性好， CdS以物理掺杂方式均匀分布于CS薄膜中， CdS颗粒尺寸在70 nm左右.但薄膜荧光光谱位置和形状表明实际发光的CdS簇集体直径小于20 nm.由此推测电镜观察到的CdS颗粒可能是由许多CdS小颗粒聚集而成，小颗粒之间因有机物的存在而相互隔离. CS/CdS纳米颗粒复合膜的荧光发射对水体中吡啶的存在十分敏感，微量吡啶的存在会引起薄膜荧光发射急剧增强.除铜和碘离子外，水体系中其他常见离子对薄膜荧光发射没有显著影响，预期CS/CdS纳米颗粒复合薄膜有可能发展成为一种重要的水体系吡啶测定专用传感薄膜材料.

Preparation of Chitosan/CdS Composite Films and Their Sensing Properties to Pyridine

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.