Directional freeze casting is a method that uses the " liquid-solid-gas" phase transformation of solvents to obtain porous materials by uniformly mixing raw materials,solvents and additives. It has the advantages of simple operation and green environmental protection. Different from the usual pore-making technology,it offers a high degree of control over the physical,chemical and mechanical properties of materials,where the materials prepared by this technology have oriented pores and hierarchical structures at different levels. Because of these characteristics,this technique is widely used in anisotropic porous inorganic,organic,hybrid and carbonaceous materials. This method can also be extended to simulate the structures of natural materials to assemble porous composites with excellent mechanical and physical properties. Finally,the method offers wide application prospects in fields such as environmental science,energy,thermal management and biology. In this paper,based on the origins and principles of directional freezing technology,the formation mechanism of a directional structure is revealed based on the force model of single and multiple particles. The effects of the solute,solvent,temperature gradient,and additives on a structure and on the properties of the materials are analyzed. In addition,according to the different means of doping modification of precursor materials,the characteristics of directional structures prepared by one-step and two-step methods are introduced. Simultaneously,the research progress of directional freezing technology in pollutant adsorption,energy storage and conversion,structural materials,thermal management,and biomaterials are summarized. Finally,the problems that must be solved in the current research are briefly described,and future developmental directions are proposed. © 2023 Cailiao Daobaoshe/ Materials Review. All rights reserved.
