Pore Size Control in Cross-Linked Polymer Resins by Reverse Micellar Imprinting

Abstract

We have synthesized highly cross-linked porous polymer resins with controlled pore sizes using the template imprinting technique. The polymer resins were prepared by dissolving reverse micelles in a mixture of monomers and cross-linkers followed by bulk polymerization initiated with a free radical initiator and UV irradiation. Styrene and divinylbenzene were used for the polymer matrix, and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) was used as the surfactant for the formation of reverse micelles. The size of the cavities inside the polymer resins was controlled by adjusting the water content in the reverse micelles prior to polymerization. The surface area, pore volume, and pore size of the polymers were determined by gas adsorption experiments. The average diameter of the pores in the polymers was found to be proportional to the water content in the micelles, hence the micellar size. The surface area and total pore volume are also influenced by the micelle/cavity size. The pore size distribution in the polymers also depends on the size of reverse micelles. With lower water content in the reverse micelles, the size of the cavities in the polymer resins is smaller and more uniform.