Fabrication of Polymeric Hollow Spheres Having Macropores by a Quenching and Sublimation Process

We fabricated polymeric hollow spheres having macropores, which combine the advantageous properties of porous materials and hollow spheres. To fabricate such spheres, a polystyrene/methylmethacrylate solution was dispersed in water by vigorously stirring and then the suspension was quenched using liquid nitrogen. Water and methyl methacrylate present in the quenched suspension were readily sublimated by freeze-drying. Conclusively, the hollow-sphere structure and the macropores of its shell were created by the processes of liquid nitrogen-quenching and sublimation of methyl methacrylate domains within the shell, respectively.