Physical and high-temperature permeation features of double-layered cellular filtering membranes prepared via freeze casting of emulsified powder suspensions

► Double-layered cellular filtering alumina membranes via freeze casting of emulsified suspensions. ► Layers cell size control via stirring rate during emulsification. ► k1 and k2 vary in opposite ways according to the airflow temperature effect. ► Different influences of thermal expansion and air slippage on the porous paths. ► Permeability levels within the range for hot aerosol filtration.