Metal-imprinted microsphere prepared by surface template polymerization with W/O/W emulsions

A Zn(II)-imprinted microsphere is prepared by surface template polymerization with W/O/W emulsions. Dioleyl phosphoric acid, which has two long alkyl chains in the hydrophobic moiety, and divinylbenzene were employed as a functional host and a cross-linking agent, respectively. In order to create a spherical imprinted polymer, composition of the external aqueous phase in the W/O/W emulsion is a key factor: the value of the ionic strength to prevent shrinking of emulsions during polymerization and the choice of the water-soluble surfactant for stabilizing the spherical W/O emulsion are important. The metal-imprinted heads exhibit a high selectivity towards target zinc ions over copper ions. The novel preparation technique is very useful for an industrial application because it can easily control the particle size between 10 and 100 mu m.