Patent ID: 8873918

Claim:
A process for the preparation of free-flowing organosilica nanoparticles, the process comprising: forming a solution of an organosilica nanoparticle precursor in a mixed solvent system comprising a first solvent and a second solvent, wherein the first solvent is different from the second solvent, wherein the second solvent has a boiling point which is greater than a boiling point of the first solvent, and wherein the nanoparticle precursor has a greater solubility in the first solvent than in the second solvent; removing at least 50% of the first solvent to form free-flowing nanoparticles having a mean particle size less than about 25 nanometers dispersed in the solution; adding a coupling agent to the solution to facilitate reacting of the coupling agent with the free-flowing nanoparticles; and recovering the free-flowing nanoparticles from the solution, wherein the recovered nanoparticles have the mean particle size of less than about 25 nanometers.