Facile fabrication of golf ball-like hollow microspheres of organic-inorganic silica

A simple procedure was developed to fabricate uniform-sized hollow organic-inorganic silica spheres with a golf ball-like wrinkled surface. Two precursors, methyltrimethoxylsilane and tetraethoxysilane were hydrolyzed in solution of ammonia, and the hollow morphology was obtained by co-condensation of the two precursors, followed by self-assembly of silica and polymeric organoalkoxysilane. The composition of the two precursors and temperature were of importance for the morphological characteristics of organic-inorganic silica spheres. In addition, their size and distribution can be controlled by the dispersion manner of precursors into aqueous solution of ammonia. The framework components indicated the presence of silica and polymethylsilsesquioxane, and polymethylsilsesquioxane was distributed on the surface of the microspheres. Self-assembly of silica and polymethylsilsesquioxane based on Ostwald ripening process was proposed to explain the formation of hollow structures and golf ball-like wrinkled surface.