Polyelectrolyte Controlled Large-Scale Synthesis of Hollow Silica Spheres with Tunable Sizes and Wall Thicknesses

High-yield synthesis of hollow silica spheres with controllable sizes and wall thicknesses can be realized by a modified Stöber method under the control of poly(acrylic acid) (PAA). This synthetic route is involved in the formation of spherical colloid aggregates in ethanol solution, hydrolysis of TEOS under control of ammonia, and the following removal of polyelectrolyte by washing. Hollow silica spheres with controllable diameters between 25 and 400 nm and wall thicknesses of several tens of nanometers can be controlled. This method can be scaled up for large-scale synthesis of hollow silica spheres and the synthesis of other inorganic materials with core−shell or hollow structures, as well as encapsulation of other materials.