A one-step fabrication and modification of HIPE-templated fluoro-porous polymer using PEG-b-PHFBMA macrosurfactant

Abstract

Polymerized high internal phase emulsion (polyHIPE) monoliths have attracted much attention because of their ease of preparation, precise control of porous structure and useful properties. For many applications, such as chromatographic separation media, reactivity or absorptivity, post-modification of surface functional groups is required to achieve the desired functionality. However, for fluoro-polymers, it has been a challenge to fabricate high-performance foams with uniform porous structures using HIPE due to the lack of suitable surfactants to stabilize the fluorinated emulsions. In our work, we proposed a bottom-up approach where the same surfactant that stabilized the water droplets within the oil phase was used to control the solid foam surface chemistry. We employed reversible addition–fragmentation chain transfer living radical polymerization to synthesize amphiphilic-fluorinated macrosurfactant (mPEG5K-PHFBMA) to stabilize water-in-oil (W/O) HIPE. Using hexafluorobutyl methacrylate as the oil-phase monomer and divinylbenzene as the cross-linking agent, we achieved a one-pot preparation of polyHIPEs based upon poly(ethylene glycol) (PEG) with biocompatible pore surfaces and potential use in tissue engineering. The effects of amphiphilic macromolecular surfactant concentration, PHFBMA block length and initiator oil/water solubility on the emulsion droplet size, pore morphology, porous surface performance and mechanical properties were studied. The PEG modification on porous surface in the polyHIPE was also confirmed by a contact angle test and water uptake experiment. It was found that short-chain fluorinated materials demonstrated very little bioaccumulation potential and consequently better environmental safety attributes. The addition of PEG gave good biocompatibility, and the properties of these porous materials may have great potential in cell tissue engineering applications.