Visible Mie Scattering from Hollow Silica Particles with Particulate Shells
Visible Mie Scattering from Hollow Silica Particles with Particulate Shells
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DOI：
10.1021/cm4039347
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发表时间：
2014-01-28
影响因子：
8.6
通讯作者：
Fowler, Patrick W.
中科院分区：
文献类型：
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作者：
Fielding, Lee A.;Mykhaylyk, Oleksandr O.;Fowler, Patrick W.
在超细硅溶胶存在下，通过苯乙烯的醇分散聚合，合成了一系列纳米复合胶体分散体。通过动态光散射测定，原始核/壳聚苯乙烯/二氧化硅纳米复合材料颗粒的平均直径为321至471 nm。在煅烧的聚苯乙烯核，发生一些收缩，但完整的空心二氧化硅壳观察到的透射电子显微镜。在目视检查时，这些二氧化硅残留物显示出显著的颜色，其根据粒径而变化。当在透射模式下检查时（即，具有照明背景）二氧化硅粉末呈现黄色至红色，但当以反射率观察时（即，具有暗背景）观察到相对强烈的蓝色/绿色。后一种现象已通过可见光反射光谱分析，并且反射率最大值取决于二氧化硅壳的尺寸，这反过来又取决于初始纳米复合材料粒径。小角X-射线散射用于测定二氧化硅纳米颗粒在原始聚苯乙烯/二氧化硅纳米复合材料颗粒和煅烧二氧化硅壳中的堆积密度。结合几何考虑，这允许计算颗粒二氧化硅壳的等效均匀二氧化硅壳厚度，然后将该参数与Retsch等人对包含均匀二氧化硅壳的中空颗粒所作的理论预测相关联（参见Retsch，M.; Schmelzeisen，M.; Butt，H. J.道：托马斯，E. L. Nano Lett.，2011，11，1389）。
A series of colloidal nanocomposite dispersions are synthesized by alcoholic dispersion polymerization of styrene in the presence of an ultrafine silica sol. The original core/shell polystyrene/silica nanocomposite particles have mean diameters ranging from 321 to 471 nm, as determined by dynamic light scattering. Upon calcination of the polystyrene cores, some shrinkage occurs but intact hollow silica shells are observed by transmission electron microscopy. On visual inspection, these silica residues display remarkable colors that vary depending on the particle diameter. When examined in transmittance mode (i.e., with an illuminated background) the silica powders appear yellow to red in color, but when viewed in reflectance (i.e., with a dark background) relatively intense blue/green colors are observed. The latter phenomenon has been analyzed by visible reflectance spectroscopy and the reflectance maximum depends on the dimensions of the silica shell, which are in turn dictated by the initial nanocomposite particle diameter. Small-angle X-ray scattering is used to determine the packing density of the silica nanoparticles, both in the original polystyrene/silica nanocomposite particles and in the calcined silica shells. Combined with geometrical considerations, this allows the equivalent uniform silica shell thickness to be calculated for a particulate silica shell and this parameter is then related to the theoretical predictions made by Retsch et al. for hollow particles comprising uniform silica shells (see Retsch, M.; Schmelzeisen, M.; Butt, H. J.; Thomas, E. L. Nano Lett., 2011, 11, 1389).