Novel Strategy To Prepare Hierarchically Porous Ceramic Microspheres via a Self-Assembly Method on Tunable...

Porous ceramic microspheres have been widely used in many fields such as drug delivery, chemical catalysis, environmental protection, noise reduction by absorption, and separation and purification. However, the methodology to prepare porous ceramic microspheres based on traditional colloidal processing routes faces the problems of precise control of the diameter, degree of sphericity, uniformity of the microstructure (size, porosity, shape, etc.), and so forth. Herein, we propose a new methodology to prepare hierarchically porous ceramic microspheres with a mechanism based on the superwettability strategy without the requirement of any special equipment or complicated procedures. In such an approach, a ceramic emulsion with an extremely low viscosity was prepared by an emulsion-assisted self-assembly method, which would be repelled on the superamphiphobic surface to form a submillimeter-sized Al₂O₃ microsphere. Compared with the traditional colloidal processing approaches to prepare ceramic microspheres, the homogeneity and precision of the ceramic microspheres prepared via our approach are much finer, while our approach is quite simple, highly efficient, and cost-saving. Moreover, the diameter of the microspheres and the microstructure of the pores (size, density, porosity, etc.) in the ceramic microspheres could be flexibly manipulated. Our methodology has solved the key problems in the preparation of ceramic microspheres which have not been solved in the past decades and provided the solution for engineering through the delicate scientific design. We anticipate that this example of the combination of superwettability science with traditional structural ceramics could provide an important application direction of advanced techniques for fabricating ceramics.