The surface-functionalized SiO2 was dispersed in an aqueous system with MMA and sodium dodecyl sulfate (SDS) in order to obtain nano-silica colloid [24] which was mixed with an aqueous solution of initiator potassium persulfate (KPS), and then charged into a flask with mechanical stirring at 55°C for 5 hours. PMMA, as the shell, was grafted onto the surface of SiO2/MPS due to the reaction of the vinyl groups between SiO2/MPS and MMA.