Department of Chemistry, The City College of the City University of New York, New York, NY 10031, United States.
J Colloid Interface Sci. 2012 Jun 1;375(1):106-11. doi: 10.1016/j.jcis.2012.02.046. Epub 2012 Mar 6.
We have utilized wet-chemical etching of ellipsoidal silica nanoparticles (ESNs) to form silica nanoshells of a range of elliptical morphologies, with the thicknesses of the ellipsoidal silica nanoshells (ESSs) controlled through variation of synthesis conditions. A mechanism has been proposed to explain how the nanoshells are formed, and we demonstrate that the porosity of the silica ellipsoid plays a role in generating silica shells. Our self-templated, wet-etching approach is an attractive alternate procedure to the approaches presently in existence for the following reasons: (i) it is a facile, one-step process that directly produces ellipsoidal silica nanoshells, while overcoming barriers (such as requirement of removing a solid-core template seed) utilized in many reported chemical etching studies; (ii) it results in ellipsoidal silica nanostructures with dimension less than 100 nm; (iii) with an appropriate etchant, the roughness of the silica shells can be well-controlled; and (iv) it results in tunable, uniform size particles with controllable shell thicknesses. Moreover, the silica materials with the unique structures might be adjusted to meet practical application requirements.
我们利用各向异性的湿化学刻蚀法，通过改变合成条件，在球形二氧化硅纳米颗粒（ESN）表面形成不同厚度的具有各种椭圆形貌的二氧化硅纳米壳（ESS）。我们提出了一个关于纳米壳形成的机制，该机制表明二氧化硅微球的多孔性在生成二氧化硅壳的过程中起到了重要作用。我们的自模板湿刻蚀法是一种很有吸引力的替代方法，与目前存在的方法相比，它具有以下优点：（i）它是一种简便的一步法工艺，可直接生成具有亚 100nm 尺寸的各向异性二氧化硅纳米壳，同时克服了许多报道的化学刻蚀研究中存在的障碍（例如需要去除固体核模板种子）；（ii）它得到的具有各向异性的二氧化硅纳米结构；（iii）使用合适的刻蚀剂，可以很好地控制二氧化硅壳的粗糙度；（iv）它可以得到具有可调尺寸和均匀壳厚的规则的纳米颗粒。此外，通过调整二氧化硅的结构，可以满足实际应用的要求。
