Amphiphilic Polyphosphazene-Stabilized High Internal Phase Emulsions toward Porous Polymers with Designed Hydrophilicity and Hydrophobicity for Selective Adsorption of Water and Oil.

Novel pickering high internal phase emulsion gels stabilized solely by soy β-conglycinin

Highly open, porous polymer or poly(high internal phase emulsion) (polyHIPE) obtained from polymerized high internal phase emulsions (HIPE) have recently attracted much attention and increasing interest in tissue engineering applications because of their excellent properties. This research is aimed at preparing and developing a process for producing polyHIPE for use as a scaffold in tissue engineering applications. Poly(styrene/ethylene glycol dimethacrylate) (poly(S/EGDMA)) loaded with hydroxyapatite was used to prepare the polyHIPE. Further improvement on hydrophilicity and biological response to tissue fluids of the polyHIPE porous polymer was carried out using a nanolayer coating via the layer-by-layer polyelectrolyte multilayer (PEM) technique. Three types of chemicals were used for coating on the surface of the polyHIPE porous polymer such as poly(sodium 4-styrene sulfonate) (PSS), gelatin (GEL), and alginic acid (ALG). The change in surface properties of the modified poly(S/EGDMA)HIPE was characterized by UV-visible spectroscopy and contact angle measurement. Further assessments consisted of cytotoxicity testing, cell attachment, and proliferation of L929, fibroblast-like cells that were seeded on the surface of the polyHIPE porous polymer. A three-dimensional structure poly(S/EGDMA)HIPE porous polymer with high porosity was successfully prepared. Moreover, it was found that surface modification encouraged poly(S/EGDMA)HIPE with a hydrophilic nanolayer, as observed by the decrease in contact angle degree and cell adhesion of L929 fibroblast-like cells, indicating that the poly(S/EGDMA)HIPE porous polymer was effectively improved by using the layer-by-layer technique. It was revealed by MTT assay that the poly(S/EGDMA)HIPE porous polymer coated with a nanolayer of a polyelectrolyte multilayer led to an enhancement in the amount of cell adhesion and proliferation on the modified poly(S/EGDMA)HIPE porous polymer. Additionally, the most effective polyelectrolyte solution for improving cell adhesion of the poly(S/EGDMA)HIPE was PSS.

The fabrication of micrometer-sized monodisperse highly porous polymer particles, of both spherical and rodlike shapes, using a simple microfluidic setup is demonstrated. Droplets were generated in a coflow device from a water-in-oil high internal phase emulsion (HIPE), hereby creating a water-in-oil-in-water (W/O/W) emulsion. The individual droplets of monomer HIPE were polymerized downstream in the channel through photopolymerization. The polymer particles produced via this strategy possess very large macropores in comparison with the more conventional porous polymer beads synthesized by inducing in situ phase separation throughout the polymerization process through the use of porogenic solvents. Epoxy-functionalized porous particles made using the HIPE microfluidic method showed superior performance in a consecutive azide and cycloaddition “click”−“click” modification procedure monitored by IR. Our microfluidic approach led to the successful miniaturization of monodisperse submillimeter spherical poly(HIPE) beads, down to diameters of 400 μm. More strikingly is the production of poly(HIPE) rods, which were obtained by using a viscous HIPE, which in coflow emulsification formed an unstable jet that broke up into rodlike sections. These rodlike droplets maintained their shapes throughout the microfluidic channel and did not relax back into spherical droplets, allowing for production of poly(HIPE) rods upon photopolymerization. The nonspherical shape in this case is not determined by confined channel geometries, which to the best of our knowledge is unprecedented as a strategy to produce nonspherical polymer particles with microfluidics.

High internal phase emulsion hierarchical porous polymer grafting polyol compounds for boron removal

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.

Incorporating surfactants within protein-polysaccharide hybrid particles for high internal phase emulsions (HIPEs): Toward plant-based mayonnaise

The ability to make stable water-in-oil (W/O) Pickering high internal phase emulsions (HIPEs) is demonstrated using microcapsules as a stabilizer. The microcapsules are prepared with glycidyl methacrylate (GMA) and poly(melamine-formaldehyde) (PMF) as core and wall materials, respectively. Using these GMA-loaded PMF-walled microcapsules as a sole stabilizer of water-in-styrene/divinylbenzene HIPE, the polymerization of this HIPE causes a closed-cell porous polymer. While with the addition of a certain amount of the nonionic surfactant Span80 to the microcapsule-stabilized HIPEs, a series of open-cell porous materials are obtained. The morphologies of the porous materials are tunable with changing the microcapsules content and/or surfactant amount in the HIPE templates. When Raft polymerization is introduced to cure these HIPEs, owing to both the self-healing agent GMA within the microcapsules and the residue of the chain-transfer agent from Raft polymerization of HIPEs, the resulting porous polymers are proved to be self-repairable. This work suggests a new type of Pickering HIPE and provides a novel idea for preparing self-healing porous materials.

Simple method for fabrication of high internal phase emulsions solely using novel pea protein isolate nanoparticles: Stability of ionic strength and temperature

PolyHIPEs: Recent advances in emulsion-templated porous polymers

Fabrication and characterization of food-grade Pickering high internal emulsions stabilized with β-cyclodextrin

Loading contents and chemical stability of lycopene were synergistically enhanced after dispersion in genipin-crosslinked-chitosan (CS) stabilized high internal phase emulsions (HIPEs). HIPEs could be prepared with the parameters for the emulsifiers of CS concentration from 0.5 to 5mg/mL, pH value from 5.5 to 7.5, and CS/genipin mass ratio from 2:1 to 20:1. High loading content of lycopene, up to 0.25 wt% was achieved, with emulsifier in the final system only 1mg/mL. As the loading contents were elevated, increasing amount of lycopene distributed in HIPEs in the form of insoluble crystals. Meanwhile, density of oil droplets decreased and the shape changed from polygon to sphere, which is supposed to be related to the interaction between the crystal and the oil-water interface. Stability of lycopene against ultraviolet, temperature, hydrogen peroxide, and iron ions was improved significantly, which could be ascribed to the layer of genipin-crosslinked-CS on oil droplet surface and the crystal status of lycopene. The storage stability of lycopene was improved tremendously after encapsulation by HIPEs. PRACTICAL APPLICATION: Low loading content of lycopene in emulsion systems is not conducive to the evaluation of its biological function in subsequent experiments, as well as their real application in food industry. It is also crucial to improve the stability of lycopene for the practical application in food industry. In this work, the loading content in delivery system and the chemical stability of lycopene are improved through encapsulation with high internal phase emulsions (HIPEs). The significance of these results may have implications in fields spanning from colloidal science to functional foods applications.

Conjugation of aminated sugar beet pectin–tannic acid nanoparticles with cinnamaldehyde at the oil–water interface to stabilize a 3D printable high-internal phase emulsion

Photopolymerised methacrylate-based emulsion-templated porous polymers

PolyHIPE are cross-linked, highly interconnected porous polymers with unique multiscale, open-pore structures that are based on high internal phase emulsions (HIPE). This work is the first to describe crystallinity in polyHIPE. This novel crystallinity was achieved by using monomers with n-alkyl side chains (acrylates and methacrylates). Such crystallinity in polyHIPE could potentially be used to produce porous shape-memory polymers. The higher the molecular mobility and the higher the molecular order (homopolymer vs copolymer, non-cross-linked vs cross-linked, acrylate vs methacrylate, long side chains vs short side chains), the higher the melting point (Tm) and the higher the crystallinity. Only the polyHIPE based on an acrylate with a relatively long (C18) side chain exhibited a significant proportion of its melting peak above room temperature and exhibited a significant heat of melting.

Controlled flavor release from high internal phase emulsions as fat mimetics based on glycyrrhizic acid and phytosterol