Preparation and characterization of monodisperse carbon cryogel microspheres

Monodisperse carbon cryogel (MCC) microspheres were synthesized through the membrane emulsification of a resorcinol-formaldehyde (RF) aqueous solution in an organic solvent using a shirasu porous glass (SPG) membrane with a controlled porous structure, followed by freeze-drying and pyrolysis in an inert atmosphere. The conditions of membrane emulsification, i.e., the pore size of the SPG membrane used and the curing temperature of the emulsion after the emulsification, were examined in terms of the effects on both the particle size distribution and the porous properties of the microspheres. As a result, independent control of the particle size and mesoporosity in the MCC microspheres was found to be possible. The mean diameter of the microspheres could be controlled by changing the pore size of the SPG membrane used for the emulsification, and the mesoporosity of the microspheres could be improved by increasing the curing temperature of the emulsion after emulsification.