Meso/Macroporous, Mechanically Stable Silica Monoliths of Complex Shape by Controlled Fusion of Mesoporous Spherical Particles

The fabrication of meso/macroporous monoliths by partial fusion of mesoporous silica spheres with the use of the pulsed current processing (PCP) method was demonstrated. Mesoporous silica spheres have been prepared by evaporation-driven surfactant templating in microdroplets. The PCP method can simultaneously subject powder bodies to a rapid temperature increase and a compressive stress. By keeping the fusing temperature low, it was possible to form a continuous body where the particles were connected by necks formed at the surface of the particles, while the mesoporous structure was retained within the particles. The structure, porosity, necking, and mechanical properties of the fused mesoporous particles are strongly dependent on the applied pressure and temperature. This novel approach allows for flexible and independent tailoring of the bimodal pore structure together with rapid production of mechanically stable monoliths of arbitrary shape and is of interest in various applications, e.g., as membranes, sensors, catalyst support, slow-release agents, chromatography, and groundwater treatment.