Synthesis and characterization of low-cost hierarchical porous silica by nanoemulsion templating: influence of nanoemulsion volume and hydrodynamic diameter

Silica as a stable and biocompatible material has attracted a great deal of interest, particularly concerning the synthesis of porous silica. Hierarchical Porous Silica (HPS) can be synthesized through nanoemulsion templating and sol–gel. The oil droplets of NE acted as a pore-forming agent and the sol-gel built the matrix around the oil droplets. The O/W-NE was prepared by the phase inversion composition (PIC) method. The effect of nanoemulsion volume (2.5, 25, and 50) and the effect of oil droplet diameter (65, 105, 150, 200, and 400 nm) on the HPS was studied. Samples were characterized by many characterization techniques. The microstructure of the samples is versatile with macropores distributed homogenously through the mesoporous silica matrix or hollow macroporous spheres. Both volume and hydrodynamic diameter of the nanoemulsions influence the microstructure through the oil/water interfacial area. The surface area ranges between 158 and 281 m2/g and the pore volume is between 0.63 and 6.59 cc/g.