Size-dependent shape evolution of silica nanoparticles into hollow structures.
Hollow silica nanoparticles can be spontaneously generated without a template on the basis of the porous nature of silica and the high surface energy on the nanometer scale. We show that solid silica particles synthesized by the Stober and microemulsion methods initially develop small pores inside the nanoparticles under slightly basic conditions as a result of base-catalyzed etching. With further reaction, those small seed pores merge into a single void to reduce the surface energy of small pores, generating well-defined hollow nanoparticles. This behavior is unique to nanometer-sized porous materials, and the shape evolution is size-dependent, reinforcing the importance of evaluating the reactivity and structural changes of nanomaterials as well as their physical properties in different size ranges. The mechanism described here provides a simple way to generate uniform hollow nanoparticles of porous materials.
Park
Sang-Jae
SJ
Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
Kim
Yoo-Jin
YJ
Park
So-Jung
SJ
D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D012822:Silicon Dioxide / Q000737:chemistry*
D012822:Silicon Dioxide