荧光碳点的微乳液法合成及包覆

Abstract

本文运用微乳液法，以柠檬酸和脲为原料成功制备出荧光碳点(CA-FCD)。对其结构和荧光性能研究结果表明：CA-FCD为无定型结构，颗粒尺寸为9.0 nm，CA-FCD在200~400 nm处有多个激发峰，其发射峰位置恒定在440 nm处，具有显著的荧光特性。该CA-FCD也展现出优异的荧光稳定性：在低浓度(0.01~0.120 mg/ml)条件下，CA-FCD受荧光物质自吸收和浓度效应影响较小；CA-FCD适合在中性及碱性(pH > 6)条件下工作；CA-FCD还具有超强的紫外耐久性(浓度为0.12 mg/ml时其半衰期为1250 min)。另外，通过原位聚合法以聚苯乙烯包覆该CA-FCD，成功得到了核–壳式结构的纳米荧光复合微球，其颗粒尺寸约为210 nm，但CA-FCD的紫外特征吸收峰发生了改变。 Fluorescent carbon dots (CA-FCDs) were prepared from citric acid and urea via micro-emulsion method. The results showed that the CA-FCDs were amorphous and the particle size was 9.0 nm. There were multiple excitation peaks (between 200 - 400 nm) for the CA-FCDs and the position of the emission peak was located at 440 nm that the carbon dots have remarkable fluorescence properties. The CA-FCDs were of excellent fluorescence stability from the fact that the self absorption and concentration effects of the CA-FCDs were small in the concentration range of 0.01 - 0.12 mg/ml. The CA-FCDs were suitable for working under neutral and alkaline conditions (pH > 6). Also, the CA-FCDs had a strong fluorescent durability that half- life was as long as 1250 min when the concentration was 0.12 mg/ml. In addition, the CA-FCDs were coated by polystyrene via in-situ polymerization, and the nano-composite microspheres with core-shell structure were obtained successfully and the particle size was about 210 nm. Then, the UV absorption peak of the coated CA-FCDs had been changed.