纳米结构的空腔二氧化硅微球的制备与缓释行为

以单分散聚苯乙烯(PS)微球作为胶体模板,采用层层静电自组装技术,交替组装聚电解质聚二烯丙基二甲基氯化铵[poly(diallyldimethylammonium chloride),PDDA]和二氧化硅纳米颗粒(10和20nm),得到核壳型聚苯乙烯/聚电解质/二氧化硅复合微球,高温煅烧除去模板PS和聚电解质,制得空腔二氧化硅微球.TEM观察的结果显示空腔二氧化硅微球呈单分散性且内部空腔呈球形;XRD图谱显示组装的二氧化硅颗粒热处理后晶化的程度很小,仍基本保持着无定形状态;N₂等温吸附-脱附实验测得用10和20nm的二氧化硅组装成的空腔二氧化硅微球的平均孔径和比表面积分别为11nm、282.71m²·g^-1和15nm、158.17m²·g^-1. 染料的装载和释放实验分别验证了空腔二氧化硅微球的腔壁具有可渗透性和缓释性.

Fabrication and Sustained Release Property of Nanostructured Hollow Silica Microspheres

Uniform hollow nanostructural hollow silica microsphers were produced by the layer-by-layer electrostatic self-assembly technique. The core-shell microspheres were constructed by alternately depositing positive polyelectrolyte PDDAMAC and silica nanoparticles (10nm, 20nm) onto the polystyrene PS microspheres which were used as the colloidal templates, then the templates were decomposed by calcination and hollow mesoporous silica microspheres come into being. TEM show monodispered silica microspheres have spherical void. XRD analyses indicate that crystallization degree of silica is nearly the same after heating treatment, which still maintain an amorphous from. The measurements of N₂ adsorption-desorption isotherms yield the surface area of the hollow spheres assembled of silica with a diameter of 10 or 20nm are 282.71m²·g^-1 and 158.17m²·g^-1, and the average pore diameters of them are 11nm and 15nm respectively. The permeability and sustained release property of hollow silica sphere were also confirmed by the experiments of dye loaded and released.