Nanomaterials dry supercritical drying
Supercritical drying is a direct drying method , a direct drying method is the liquid phase precipitate obtained directly ( or simply filtered after washing ) using conventional drying or high temperature calcination product obtained nanomaterials method of operation .
    The so-called supercritical drying in the pressure vessel ( ie, a supercritical dryer ), of the porous solid material in the liquid components ( water, an organic solvent , a mixture of water and an organic solvent, etc. ) in its supercritical state was removed , and obtain a porous solid product separation process . When the material towel liquid solvent state exceeds its critical temperature and critical pressure , the liquid becomes a supercritical fluid , gasoline - tuck interface ceased to exist , eliminating the influence of surface tension , namely capillary pressure becomes zero , thereby avoiding microporous gel during drying collapse , the network is damaged , it can prevent the agglomeration of the nanoparticles .
    The critical temperature of the water up to 375 ℃, the critical pressure up to 22MPa, and water in a supercritical state prone to dissolve the gel problem , therefore , is not suitable for supercritical drying the hydrogel . Currently mostly used before replacement supercritical drying .