单分散荧光微球的制备及其光学性能研究

Preparation of monodisperse fluorescent microspheres and their optical properties

采用两步分散聚合法通过包覆负载染料的方式制备了单分散聚苯乙烯荧光微球。以高分子质量(Mw=300000g/mol)的聚乙烯吡咯烷酮作稳定剂,采用间断式连续滴加染料单体的方式进行制备。该方法制备的荧光微球单分散性好(标准偏差<7%),染料负载效率高。扫描电镜显示微球粒径均匀,表面形态光滑均匀,无明显缺陷。通过比较发现在微球球壳的保护作用下,染料可有效避免荧光猝灭,荧光信号比同浓度的溶液高几个数量级;此外,微球荧光发射稳定,不受外界环境介质变化的影响。

Fluorescent monodisperse polystyrene microspheres were prepared by dispersion polymerization by modified two stage dispersion polymerization in which polyvinylpyrrolidone with high molecular weight （Mw =300 000 g/mol） was used as the stabilizer and the dye was added in a relative long period after nucleation stage. Two stage dispersion polymerization combined with embedment method resulted in more uniform microspheres and higher dye concentration compared to adsorption and conventional dispersion polymerization method. The surface morphology,average diameter,size distribution and photoluminescence properties of microspheres were investigated. The found intense fluorescence and fluorescent resistance to the solvents indicate that the microsphere structure protects dye molecules from fluorescence quenching and ambient medium. This type of monodisperse fluorescent microspheres has potential application in bioassays.