Fabrication of porous clay materials with aligned pore structures by freeze-drying

Porous clay materials with columnar type pore channels were fabricated from water-based clay slurry and a specially designed mold by using a freeze casting technique. Ice was stimulated to grow vertical direction, and aligned macro pores were formed to the same direction. The phase separation between the ice and clay particles might be responsible for the formation of the columnar type pores. It appears that it is possible to control the size and morphology of pores by modifying a freezing mold, refrigerant temperature, and the weight fraction of clay in slurry.