Facile one-pot emulsion/sol-gel method for preparing wrinkled silica microspheres

The present manuscript describes a facile and versatile method for preparing uniform wrinkled silica microspheres with diameters of tens of microns. The method comprises a one-pot emulsion/sol-gel method using silica precursors of organosilane and tetraethoxysilane. By controlling the sol-to-gel transition of the silica precursors, a series of silica microspheres based on uniform emulsion droplets was synthesized by membrane emulsification. The silica microspheres had a variety of surface morphologies ranging from smooth, maze-like wrinkles to polygon-like ravines. It was possible to alter the surface morphologies of the microspheres by controlling the amount of organosilane in the dispersed phase and the amount of ammonia catalyst in the continuous phase of the emulsion. The grooves on the wrinkled microspheres were able to trap polymer nanoparticles of matching size, thereby demonstrating the potential usefulness of the microspheres in separation science and drug delivery.