Preparation of meso-macroporous TiO2 ceramic based on membrane jet-flow emulsification--influences of triblock copolymers on the processes.
ABSTRACT Meso-macroporous TiO(2) ceramics were obtained based on a two-stage ceramic membrane jet-flow emulsification and the influences of the triblock copolymers on the process are discussed in this study. The two alpha-Al(2)O(3) ceramic membranes with average pore sizes of 0.5 and 1.6 microm were used to control the structure of nonaqueous emulsions. Polyethylene oxide (PEO)-polypropylene oxide (PPO)-polyethylene oxide (PEO) with relative molecular masses of 5800 and 2900 were used as emulsifiers. Monodispersed emulsions with the same average droplet size of 2.6 microm were prepared using the two emulsifiers. However, ordered macroporous structures could only be obtained when the PEO-PPO-PEO of 5800 was used as emulsifier because the lower interfacial tension leans to produce the more stable nonaqueous emulsion. Moreover, the mesoporous structures of 5.4 nm and 7.1 nm could be obtained by the self-assembling block copolymers.