with KBr pellets
for solid specimens.
The TGA was implemented with a Seiko TG/DTA 220. The samples were heated at the rate of 10 °C/min under a nitrogen flow from 30 to 200 °C and heated at the rate of 5 °C/min under a nitrogen flow from 200 to 600 °C for the TGA measurement. The morphologies of the silica powders were measured using TEM (JEOL TEM-2010). The average size of emulsion droplets in MCX-MS-E was measured by Microtrac S3000. The in vitro SPF was measured according to the method reported [13] with a SPF-290S computer operated analyzer system (Optometrics Corp, USA).