Interconnected Porous Polymers with Tunable Pore Throat Size Prepared via Pickering High Internal Phase Emulsions

Abstract

Interconnected macroporous polymers were prepared by copolymerizing methyl acrylate (MA) via Pickering high internal phase emulsion (HIPE) templates with modified silica particles. The pore structure of the obtained polymer foams was observed by field-emission scanning electron microscopy (FE-SEM). Gas permeability was characterized to evaluate the interconnectivity of macroporous polymers. The polymerization shrinkage of continuous phase tends to form open pores while the solid particles surrounding the droplets act as barriers to produce closed pores. These two conflicting factors are crucial in determining the interconnectivity of macroporous polymers. Thus, poly-Pickering HIPEs with high permeability and well-defined pore structure can be achieved by tuning the MA content, the internal phase fraction, and the content of modified silica particles.

One‐step Preparation of Monodisperse Multifunctional Macroporous Particles through a Spontaneous Physical Process

“…The distribution of PS‐ b ‐P4VP and Fe 3 O 4 in the porous particles was shown using an energy dispersive spectrometer (EDS) (Figure g) and transmission electron microscopy (TEM) (Figure h,i and Figure S7, Supporting Information). In agreement with the literature, our magnetic nanoparticles were adsorbed at the emulsion interfaces, where they ultimately formed a layer of aggregates on the pore wall . Subsequently, we confirmed that the stability of the HIPE droplets was mainly derived from a balanced adsorption of PS‐ b ‐P4VP and Fe 3 O 4 at the interface of the water droplets, presumably because this balanced adsorption prevented the small droplets from coalescing .…”

Fabrication of CMC-g-PAM Superporous Polymer Monoliths via Eco-Friendly Pickering-MIPEs for Superior Adsorption of Methyl Violet and Methylene Blue

“…In this process, the coalescence of partially neighboring droplets, the volume shrinkage caused by polymerization of monomers, and the separation of surfactant-rich phase and polymer-rich phase contributed to the formation of open pores (Cameron et al, 1996; Xu et al, 2015). …”

“…In Pickering-HIPEs, nanoparticles are present at the oil/water (O/W) interface, evenly packed around the emulsion droplets to form a dense protective layer, so that the size of Pickering emulsion droplets are larger than the dropletes stabilized with surfactants (Xu et al, 2015). There are gaps between the accumulated emulsion droplets, which can accommodate the monomers to form the monomer layer.…”

“…First, continuous phase currently used to prepare Pickering emulsion is a toxic organic solvent, and the nanoparticles used to stabilize Pickering emulsion are mainly synthetic nanoparticles. Second, the polymerization of monomers in the Pickering-HIPEs stabilized with only nanoparticles usually produces porous polymer materials with a super closed-cell pore, typically between 200 and 700 μm, which limited the permeability of the porous material (Xu et al, 2015). So, it would be a feasible approach to reduce the volume of dispersion phase and replace the potentially toxic organic solvents and nanoparticles with naturally available ones are the effective approaches to solve the problems.…”

High Internal Phase Emulsion Ring‐Opening Polymerization of Pentadecanolide: Strategy to Obtain Porous Scaffolds in a Single Step

“…HIPE is characterized for its high volume fraction of dispersed phase (>0.74) . The work has so far been expanded for free‐radical polymerization of variety of vinylic monomers forming the continuous phase of a water‐in‐oil HIPE . The initiators (thermal as well as photoinitiators) used were monomer soluble and the scaffolds thus developed were characterized for their high porosity and interconnectedness of pores .…”