3.50 g silica nanoparticles (aerosil 380) and 200 mL anhydrous
toluene were added into a round flask. After 60 min of sonication,
5 mL 3-(triethoxysilyl)-propylamin was added dropwise to the
above solution. The mixture was stirred at 90 C overnight. After
cooling to room temperature, the surface modified silica nanoparticleswere
collected by centrifuge, thenwashed with 2-propanol
three times. The obtained amino modified silica nanoparticles were
re-dissolved into 200 mL 2-propanol to avoid aggregation.