Development of mesoporous SiO2/CeO2 core/shell nanoparticles with tunable structures for non-damage and efficient polishing

For abrasive particles, the type, morphology, structure, size and distribution, physio-chemical properties are usually considered as key influential factors which determine the ultra-precision polishing performance. It is commonly recognized that the structure design, surface modification, and doping treatment of abrasives contribute to achieving high-quality and high-efficiency polishing. Herein, we report the fabrication of sub-100 nm monodispersed dendritic-like mesoporous silica (D-mSiO(2)) with tunable structures via an oil-water biphase stratification approach. A CeO2 thin shell was subsequently coated on the D-mSiO(2) nanospheres forming core/shell structured D-mSiO(2)/CeO2 composites. The samples were examined via XRD, SEM, TEM, SAED, DLS, FTIR, and nitrogen adsorption-desorption measurements. The polishing characteristics of the D-mSiO(2)/CeO2 nanoabrasives over silica films were tracked by atomic force microscopy and noncontact interferometric microscopy. Compared with commercial ceria particles, the obtained D-mSiO(2)/CeO2 nano-abrasives were favorable for mechanical scratch elimination and removal rate enhancement. Furthermore, an enlarged pore volume or porosity of D-mSiO(2) cores achieved an atomic-scale surface with relatively low roughness, less variation, and enhanced removal rate. The mechanism of high-efficiency and defect-free polishing for the CeO2-based composites was discussed. These results may provide promising guidance in the design and optimization of novel particle abrasives.