Preparation of macroporous hydrophobic materials filled with aligned porous hydrophilic domain via emulsion-templated and unidirectional freezing technique.

A new class of porous materials, having hydrophobic scaffold embedded with aligned porous hydrophilic domains, was in situ fabricated through combination of emulsion-templated method and unidirectional freezing technique. A water-in-oil high internal phase emulsion (HIPE) was prepared with the mixture of styrene and divinylbenzene as continuous phase and a poly(vinyl alcohol) (PVA) aqueous solution as dispersed phase. After polymerization of the continuous phase and subsequently unidirectional freezing, the dispersed phase, a macroporous poly(styrene/divinylbenzene) embedded with an aligned PVA domain, was obtained. The effects of the polymerization temperature, PVA concentration, and freezing rate on these porous materials were investigated. It was found that the PVA domain size and the aligned channel size were dependent on the polymerization temperature, the PVA concentration, and freezing rate. The fabrication method in this work, combining of unidirectional freezing and emulsion template, not only allows to prepare hydrophobic-hydrophilic polyHIPEs having a sea island structure but also dramatically improves the stiffness and specific surface area of the resulting polyHIPEs. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]