Macroporous polymers from particle-stabilized emulsions

Abstract

Macroporous polymers are attractive materials due to their low density, low cost, recyclability and tunable mechanical and functional properties. Here, we report a new approach to prepare macroporous polymers from emulsions stabilized with colloidal polymeric particles in the absence of chemical reactions. Stable water-in-oil emulsions were prepared using poly(vinylidene difluoride) (PVDF), poly(tetrafluoroethylene) (PTFE), and poly(etheretherketone) (PEEK) as stabilizing polymeric particles in emulsions. The partial wetting of the polymeric particles by the two immiscible liquids drives particles at the water–oil interface during emulsification, leading to extremely stable water-in-oil emulsions. The particle-stabilized emulsions were processed into highly porous solid polymer components upon drying and sintering. The high stability of emulsions also allows for the preparation of hollow polymeric microcapsules. We describe the conditions required for the adsorption of particles at the liquid–liquid interface, we show the rheological behavior of the polymer-loaded wet emulsions and, we discuss the effect of the emulsions' initial compositions on the final sintered porous structures. This new approach for the fabrication of macroporous PVDF, PTFE, and PEEK polymers is particularly suited for the preparation of porous materials from intractable polymers but can also be easily applied to a variety of other polymeric particles.