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

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.

Ultrarobust and Biomimetic Hierarchically Macroporous Ceramic Membrane for Oil-Water Separation Templated by Emulsion-Assisted Self-Assembly Method.

Reported herein is a novel ultrarobust and biomimetic hierarchically macroporous ceramic membrane that can achieve a high efficiency of up to 99.98% for oil-water separation, while the efficiency remains nearly unchanged even after 10 rounds of use and storage for up to 4 months. The macroporous ceramic membrane is prepared by combining surface hydrophobic coating with an emulsion-assisted template self-assembly of the modified Al2O3 ceramic powder. The as-prepared ceramic membrane is a lightweight material with high strength because the relative density is only ∼1.02 g/cm3; the compressive strength of the as-prepared ceramic membrane is expected to be 15-fold higher than that of the sample prepared using the traditional solid template approach even at a higher porosity due to the principle of self-assembly of Al2O3 particles. It is the mechanism of self-assembly that has broken the traditional principle in ceramic preparation that leads to a perfectly dense packing structure. Moreover, the ceramic membrane maintained excellent oil-water separation efficiency, because of which even after its top layer was damaged by sand impingement, superfine particles could be separated using our macroporous membrane due to the featured interconnected pore structure. We anticipate that this example of the combination of a superwettability theory and a traditional ceramic material can provide an important application direction of advanced oil-water separation techniques.