PS@SiO_(2)微球的合成及其三维光子晶体的光学性能

Synthesis of PS@SiO2 Microsphere and Optical Properties of Its Three-Dimensional Photonic Crystals

以乙烯基三乙氧基硅烷为硅源,通过其在碱性条件下的水解缩聚,在聚苯乙烯(PS)微球表面包覆乙烯基修饰的二氧化硅(Vi-SiO_(2))壳层制备PS@SiO_(2)微球,并通过刮涂法进一步制得PS@SiO_(2)三维光子晶体。对比了PS微球在包覆Vi-SiO_(2)前后的微观形貌、粒径和化学组成的差异,分析了PS@SiO_(2)光子晶体的形貌和光学性能。结果表明:Vi-SiO_(2)在PS微球表面形成了均匀且光滑的外壳,并且Vi-SiO_(2)的包覆对PS微球的单分散性和球形度无明显影响。由4种不同粒径的PS@SiO_(2)微球自组装的三维光子晶体都具有规则的面心立方结构,其结构色随PS@SiO_(2)微球粒径的增大发生红移,并且都具有虹彩效应。

By coating vinyl-modified silicon(Vi-SiO_(2))shell on the surface of polystyrene(PS)microspheres in alkaline medium,PS@SiO_(2) microspheres were synthesized using vinyltriethoxysilane(VTES)as silicon source.Subsequently,PS@SiO_(2) three-dimensional(3D)photonic crystals were prepared by rod-coating method and their optical properties were investigated.The synthesized PS microspheres and PS@SiO_(2) microspheres were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),and infrared spectroscopy.Results showed that the stretching vibration absorption peaks of Si―O―Si at 1155 cm-1 and 1044 cm-1 in the infrared spectra proved the synthesis of Vi-SiO_(2).The PS@SiO_(2) microspheres had an obvious core-shell structure,with a Vi-SiO2 shell thickness of about 20 nm.At the same time,Vi-SiO_(2) formed a uniform and smooth shell on the surface of PS microspheres.Importantly,the coating of Vi-SiO_(2) had no significant effect on the monodispersity and sphericity of PS microspheres.The synthesized PS@SiO_(2) microspheres had particle sizes of 211,230,251 nm,and 270 nm,respectively.The cores of PS@SiO2 microspheres were PS microspheres with particle sizes of 177,197,218 nm,and 240 nm,respectively.Photonic crystals assembled from PS@SiO_(2) microspheres of four different particle sizes exhibited blue,green,yellow,and red structural colors,respectively,and the corresponding reflectance spectra showed reflection peaks at 475,525,575 nm,and 650 nm,respectively.Meanwhile,SEM images of photonic crystals assembled from PS@SiO_(2) microspheres of four different particle sizes all proved that PS@SiO_(2) photonic crystals had a regular face-centered cubic structure.In addition,PS@SiO_(2) photonic crystals displayed different structural colors at different viewing angles,meaning that they possessed iridescent effects.