Methyl Methacrylate HIPE Solely Stabilized by Fluorinated Di‐block Copolymer for Fabrication of Highly Porous and Interconnected Polymer Monoliths

Abstract

Preparation of stable water-in-oil (W/O) high internal phase emulsion (HIPE) containing methyl methacrylate (MMA) monomer as oil phase is a difficult task due to the significant solubility of MMA in water. Here, for the first time a fluorinated di-block copolymer (FDBC) poly (2-dimethylamino)ethylmethacrylate-b-poly (trifluoroethyl methacrylate) (PDMAEMA-b-PTFEMA) is proposed to stabilize HIPEs of MMA without the use of any co-stabilizer or thickening agent. Fluorinated segments in FDBC anchored well at oil/water interface of HIPE, offering high hydrophobicity to the partially hydrophilic MMA monomer and in turn stabilization to MMA-HIPE. By using fluorinated di-block copolymer as stabilizer, highly stable HIPEs can be obtained. In addition, highly interconnected porous monoliths were obtained after free radical polymerization, which are highly desirable materials in various practical applications including tissue engineering scaffolds, separation science, bio-engineering and so on. The as-prepared MMA-HIPEs possess high thermal stability without phase separation. The textural characteristics of as-prepared composites, such as pore size and distribution, can be easily controlled by simply varying the amount of FDBC and/or dispersed phase fraction. Moreover, the influence of di-block concentration on water uptake (WU) capability of the prepared porous monoliths is explored.

Emulsion Templating: Porous Polymers and Beyond

“…Complex HIPE stabilization systems are becoming increasingly prevalent and include a fluorinated BCP, gemini surfactants (two connected monomeric surfactants), surfactant mixtures that are tuned using a phase diagram, and monomeric BCP surfactants. , Macromolecular surfactants were used for a CO 2 -in-ionic liquid HIPE containing vinyl-bearing ionic liquid monomers and cross-linkers, and a hyperbranched hydrolyzable polyethoxysiloxane surfactant was used to produce highly porous silica monoliths from w/o HIPEs . Recent approaches to reducing the high surfactant contents that are a predominant challenge to industrial adoption of emulsion templating include limiting the HIPE’s ability to phase separate, combining freezing and UV polymerization, and, more commonly, using Pickering HIPEs where the presence of NPs can be leveraged to provide additional functionalities.…”

“…Complex HIPE stabilization systems are becoming increasingly prevalent and include a fluorinated BCP, 315 gemini surfactants (two connected monomeric surfactants), 316 surfactant mixtures that are tuned using a phase diagram, 317 and monomeric BCP surfactants. 41,42 Macromolecular surfactants were used for a CO 2 -in-ionic liquid HIPE containing vinylbearing ionic liquid monomers and cross-linkers, 318 and a hyperbranched hydrolyzable polyethoxysiloxane surfactant was used to produce highly porous silica monoliths from w/o HIPEs.…”

Preparation of fluoropolymer materials with different porous morphologies by an emulsion template method using supercritical carbon dioxide as a medium

“…At the same time, based on the preparation of C/W emulsion, the stability of the emulsion and the shape of the polymer can be controlled from the selection of different co-surfactants, 47 adjusting the concentration of surfactant, amount of crosslinker and the ratio of water to CO 2 . However, unexpected problems were noted in the experiments, when the concentration of surfactant was higher than 15%, whereby the polymer exhibited a large transformation in the morphology and the stability of emulsion became poor.…”

“…Because of the presence of -CF 3group in TFEMA which has a low surface energy which is strictly required for the material to have hydrophobicity or lipophilicity, and also used in preparation of di-block copolymers. 46,47 For the polymers with three different morphology prepared by three surfactants (Fig. 4(B1), (B3) and (B4)), four oil phases (n-hexane, petroleum ether, toluene and dichloromethane) were selected for testing the adsorption of oil.…”

A facile fabrication of porous fluoro-polymer with excellent mechanical properties based on high internal phase emulsion templating using PLA as co-stabilizer

“…11,12 For the HIPE system, the styrene-, acrylate-or uoromonomers used as the external phase must remain stable when mixed with the aqueous internal phase. 13 A surfactant can be used to control the dispersed droplets and create voids and pore throats aer polymerization. Williams 14 demonstrated that styrene containing porous material could be prepared via the emulsion template method using Span 80 surfactant.…”