Polymerized High Internal Phase Emulsion Research Articles

Synthesis and Applications of Elastomeric Polymerized High Internal Phase Emulsions (PolyHIPEs).

Polymer foams (PFs) are among the most industrially produced polymeric materials, and they are found in applications including aerospace, packaging, textiles, and biomaterials. PFs are predominantly prepared using gas-blowing techniques, but PFs can also be prepared from templating techniques such as polymerized high internal phase emulsions (polyHIPEs). PolyHIPEs have many experimental design variables which control the physical, mechanical, and chemical properties of the resulting PFs. Both rigid and elastic polyHIPEs can be prepared, but while elastomeric polyHIPEs are less commonly reported than hard polyHIPEs, elastomeric polyHIPEs are instrumental in the realization of new materials in applications including flexible separation membranes, energy storage in soft robotics, and 3D-printed soft tissue engineering scaffolds. Furthermore, there are few limitations to the types of polymers and polymerization methods that have been used to prepare elastic polyHIPEs due to the wide range of polymerization conditions that are compatible with the polyHIPE method. In this review, an overview of the chemistry used to prepare elastic polyHIPEs from early reports to modern polymerization methods is provided, focusing on the applications that flexible polyHIPEs are used in. The review consists of four sections organized around polymer classes used in the preparation of polyHIPEs: (meth)acrylics and (meth)acrylamides, silicones, polyesters and polyurethanes, and naturally occurring polymers. Within each section, the common properties, current challenges, and an outlook is suggested on where elastomeric polyHIPEs can be expected to continue to make broad, positive impacts on materials and technology for the future.

Synthesis of patterned polyHIPE-hydrogel composite materials using thiol-ene chemistry

Elastomeric materials combining multiple properties within a single composite are highly desired in applications including biomaterials interfaces, actuators, and soft robotics. High spatial resolution is required to impart different properties across the composite for the intended application, but many techniques used to prepare these composites rely on multistep and complex methods. There is a need for the development of simple and efficient platforms to design layered composite materials. Here, we report the synthesis of horizontally- and vertically-patterned composites consisting of PDMS-based polymerized high internal phase emulsion (polyHIPE) porous elastomers and PDMS/PEG hydrogels. Composites with defined interfaces that were mechanically robust were prepared, and rheological analysis of the polyHIPE and hydrogel layers showed storage moduli values of ∼ 35 kPa and 45 kPa respectively. The compressive Young’s Modulus and maximum strain of the polyHIPEs were dependent on the thiol to ene ratio in the formulation and obtained values ranging from 6 to 25 kPa and 50–65% respectively. The mechanical properties, total porosity of the polyHIPE, and swelling ratio of the hydrogel were unaffected by the patterning technique compared to non-patterned controls. PolyHIPE-hydrogel composite materials having up to 7-different horizontally pattered layers could be prepared that could expand and contract up hydration and drying.

Acid-Activated Organobentonite-Based Highly Porous Foams via Polymerized High Internal Phase Emulsion: Preparation, Characterization and Machine Learning Prediction

Preparation, characterization, and machine learning prediction of characteristics of acid-treated organobentonite-based highly porous foams via polymerized high internal phase emulsion were reported in this work. The effect of acid-treated organobentonite (AC-BTN) as an inorganic filler on the properties of poly(DVB)HIPE porous foam was experimentally investigated. Incorporating AC-BTN into the continuous phase of the high internal phase emulsion would improve thermal and mechanical properties and also increase the surface area of the resulting materials when compared to the unfilled poly(DVB)HIPE foam. Various amounts of AC-BTN, i.e., 0, 1, 3, 5, 7, and 10 wt.% of AC-BTN, were incorporated into the continuous phase to enhance the properties of poly(DVB)HIPE foam. The surface area and the degradation temperatures (Td) for the series of poly(DVB)HIPE foam filled with AC-BTN increased with increasing filler content from 0 to 10 wt.%. The maximum improvement of mechanical properties was found with the addition of 5 wt.% of AC-BTN into the continuous phase of poly(DVB)HIPE foam. Moreover, the adsorption of CO2 gas by poly(DVB)HIPE foam filled with AC-BTN was found to increase as well. It has been demonstrated in this study that the adsorption of CO2 by poly(DVB)HIPE foam filled with AC-BTN increased by 127% (from 0.00295 to 0.00670 mol/g) compared with neat poly(DVB)HIPE foam. Additionally, the machine learning (ML) method with a linear regression algorithm was employed for the characterization of poly(DVB)HIPE foam and the prediction of properties according to composite composition. Surface area, pore volume, Td, compressive stress, and Young’s modulus were evaluated. The accuracy of prediction using a machine learning application with a linear regression model for properties of poly(DVB)HIPE foam filled with AC-BTN was also reported.

Metal Oxide-Derived MOF-74 Polymer Composites through Pickering Emulsion-Templating: Interfacial Recrystallization, Hierarchical Architectures, and CO2 Capture Performances

Currently, metal-organic framework (MOF)-polymer composites are attracting great interest as a step forward in making MOFs a useful material for industrially relevant applications. However, most of the research is engaged with finding promising MOF/polymer pairs and less with the synthetic methods by which these materials are then combined, albeit hybridization has a significant impact on the properties of the new composite macrostructure. Thus, the focus of this work is on the innovative hybridization of MOFs and polymerized high internal phase emulsions (polyHIPEs), two classes of materials that exhibit porosity at different length scales. The main thrust is the in situ secondary recrystallization, i.e., growth of MOFs from metal oxides previously fixed in polyHIPEs by the Pickering HIPE-templating, and further structure-function study of composites through the CO2 capture behavior. The combination of Pickering HIPE polymerization and secondary recrystallization at the metal oxide-polymer interface proved advantageous, as MOF-74 isostructures based on different metal cations (M2+ = Mg, Co, or Zn) could be successfully shaped in the polyHIPEs' macropores without affecting the properties of the individual components. The successful hybridization resulted in highly porous, co-continuous MOF-74-polyHIPE composite monoliths forming an architectural hierarchy with pronounced macro-microporosity, in which the MOF microporosity is almost completely accessible for gases, i.e., about 87% of the micropores, and the monoliths exhibit excellent mechanical stability. The well-structured porous architecture of the composites showed superior CO2 capture performance compared to the parent MOF-74 powders. Both adsorption and desorption kinetics are significantly faster for composites. Regeneration by temperature swing adsorption recovers about 88% of the total adsorption capacity of the composite, while it is lower for the parent MOF-74 powders (about 75%). Finally, the composites exhibit about 30% improvement in CO2 uptake under working conditions compared to the parent MOF-74 powders, and some of the composites are able to retain 99% of the original adsorption capacity after five adsorption/desorption cycles.

Macroporous carbon coatings through carbonization of emulsion-templated poly(dicyclopentadiene) on metal substrates

In this article, we demonstrate the fabrication of thin and macroporous carbon coatings that adhere to various metal substrates such as nickel- or aluminum-based foils or meshes. The coating process is a combination of emulsion-templating and the doctor-blade method, which allows to prepare up to 350 µm thick poly(dicyclopentadiene) membranes with a polyHIPE (polymerized high internal phase emulsions) architecture. Carbonization of these poly(dicyclopentadiene) membranes directly on the metal substrates resulted in up to 30-µm-thick foamy carbon coatings that retain the highly porous architecture and flexibility. Subsequently, carbon foam-coated Ni-foils were filled with elemental sulfur by a melt diffusion technique. A macroporous carbon coating supported sulfur loadings up to 65 wt%, obtaining cathodes for galvanostatic cycling experiments in Li–S cells. The latter revealed discharge capacities higher than 800 mA h−1 according to the sulfur mass. With our approach, the final assembly of the electrodes is greatly simplified because no binders or conductive fillers are required.Graphical abstract

Open-cell PDMS polyHIPEs prepared using polymethylvinylsiloxane to prevent pore collapse

Polymerized high internal phase emulsions (PolyHIPEs) are porous polymers made using an emulsion template. Our group has previously shown that polydimethylsiloxane (PDMS) polyHIPEs prepared using a thiol-ene crosslinking reaction could obtain a maximum total porosity of ∼63%. Attempting to increase total porosity by increasing the volume fraction dispersed phase resulted in collapse of the porous material due to the soft nature of PDMS. In this work, polymethylvinylsiloxane (PMVS) was synthesized to impart high crosslinking density in the network. This polymer can be blended with divinyl-PDMS in the continuous phase to obtain a large range of storage moduli (25–900 kPa) in the final polyHIPEs with higher total porosity (74–77%). Finally, the use of these PDMS PolyHIPEs as separation media for oil/water mixtures has been demonstrated.

Highly interconnected porous monolithic and beaded polymers using high internal phase emulsion polymerization: tuning porous architecture through synthesis variables

AbstractOpen porous polymeric materials have gained popularity due to their exceptional properties and applications in tissue engineering scaffolds, drug delivery, enzyme immobilization and catalysis support. This study developed a novel two‐stage approach to create networked, crosslinked poly(2‐hydroxyethyl methacrylate‐co‐N,N′‐methylenebisacrylamide) HEMA‐MBA beads. The first part involves producing an oil‐in‐water‐in‐oil high internal phase emulsion (HIPE). This is followed by suspension polymerization using a redox initiator pair. In this study, a mixed surfactant combination with low and high hydrophilicity–lipophilicity balance surfactants was identified and successfully utilized to prepare a stable oil‐in‐water‐in‐oil HIPE. The effect of crosslinker concentration (i.e. crosslink density), surfactant concentration and monomer‐to‐porogen ratio on pore architecture and surface area were successfully evaluated. In addition, a new protocol was developed to synthesize HEMA‐MBA monoliths using an oil‐in‐water HIPE method at ambient temperature using a redox initiator pair. The effect of crosslink density and oil phase on pore architecture and surface area was evaluated. Key variables affecting the morphology of porous HEMA‐MBA beads and monoliths were identified and quantified, allowing future development of porous HEMA‐based polymer beads and monoliths with tunable morphologies which are suitable for numerous applications, especially in the biomedical field. © 2022 Society of Industrial Chemistry.

Fabrication of three‐dimensional porous superhydrophobic composites for immiscible and emulsified oil/water mixture separation

AbstractDue to ever‐increasing environmental problems caused by oily wastewater, it is necessary to develop methods for separating oil/water mixtures. However, oil‐in‐water and water‐in‐oil emulsions are highly stable due to the action of surfactants, making them enormously difficult to separate. In this study, we report a 3D superhydrophobic/superoleophilic porous material with a microporous structure and strong negative charge via high internal phase emulsion polymerization to overcome these difficulties. The introduction of 10 wt% α‐zirconium phosphate significantly improved the hydrophobicity of the material (water contact angle = 153°) and also endowed the material with a strong negative charge. The material could separate immiscible oil/water mixtures under turbulent condition and high‐ or low‐temperature environments. Driven by gravity, the as‐prepared monolith separated various oil/water mixtures with the separation efficiency exceeding 99.16%. Benefiting from the diametrically‐opposing wettability and interconnected micropore structure, the foam could separate a Span 80‐stabilized water‐in‐oil emulsion. Furthermore, a cationic surfactant‐stabilized oil‐in‐water emulsion was also separated due to strong electrostatic interactions, which destabilized the oil/water interfacial film. Based on these properties, the as‐prepared porous material shows huge potential for complex oily wastewater treatment.

Porous Polymerized High Internal Phase Emulsions Prepared Using Proteins and Essential Oils for Antimicrobial Applications.

High internal phase emulsions (HIPEs) provide a versatile platform for encapsulating large volumes of therapeutics that are immiscible in water. A stable scaffold is obtained by polymerizing the external phase, resulting in polyHIPEs. However, fabrication of polyHIPEs usually requires using a considerable quantity of surfactants along with nonbiocompatible components, which hinders their biological applications, e.g., drug-eluting devices. We describe here a straightforward method for generating porous biomaterials by using proteins as both the emulsifier and the building blocks for the fabrication of polyHIPEs. We demonstrate the versatility of this method by using different essential oils as the internal phase. After the gelation of protein building blocks is triggered by the addition of reducing agents, a stable protein hydrogel containing essential oils can be formed. These oils can be either extracted to obtain protein-based porous scaffolds or slowly released for antimicrobial applications.

Preparation of Interconnected Pickering Polymerized High Internal Phase Emulsions by Arrested Coalescence.

Emulsion templating is a method that enables the production of highly porous and interconnected polymer foams called polymerized high internal phase emulsions (PolyHIPEs). Since emulsions are inherently unstable systems, they can be stabilized either by surfactants or by particles (Pickering HIPEs). Surfactant-stabilized HIPEs form materials with an interconnected porous structure, while Pickering HIPEs typically form closed pore materials. In this study, we describe a system that uses submicrometer polymer particles to stabilize the emulsions. Polymers fabricated from these Pickering emulsions exhibit, unlike traditional Pickering emulsions, highly interconnected large pore structures, and we related these structures to arrested coalescence. We describe in detail the morphological properties of this system and their dependence on different production parameters. This production method might provide an interesting alternative to poly-surfactant-stabilized-HIPEs, in particular where the application necessitates large pore structures.

Preparation of a Dual-Functionalized Acid-Base Macroporous Polymer via High Internal Phase Emulsion Templating as a Reusable Catalyst for One-Pot Deacetalization-Henry Reaction.

A macroporous dual-functional acid–base covalent organic polymer catalyst poly(St-VBC)-NH2-SO3H was prepared using high internal phase emulsion polymerization using vinylbenzyl chloride (VBC), styrene (St), and divinylbenzene (DVB) as substrates toluene as a porogenic solvent, and subsequent modification with ethylenediamine and 1,3-propane sultone. The role of various amounts of toluene as the porogenic solvent as well as the amount of 1,3-propane sultone (different ratio of acid/base sites) on the structure of the prepared materials have been carefully investigated. The prepared materials were characterized by Fourier transform infrared (FT-IR), CHNS elemental analysis, energy-dispersive X-ray (EDX), elemental mapping, field emission scanning electron microscopy (FE-SEM), and thermalgravimetric analysis (TGA). The catalytic activity of the poly(St-VBC)-NH2-SO3H series with different acid/base densities was assessed for one-pot cascade C–C bond-forming reactions involving deacetylation–Henry reactions. The poly(St-VBC)-NH2-SO3H(20) sample bearing 1.82 mmol/g of N (base site) and 1.16 mmol/g (acid site) showed the best catalytic activity. The catalyst demonstrated superior activity compared to the homogeneous catalysts, poly(St-DVB)-SO3H+EDA, poly(St-VBC)-NH2+chlorosulfonic acid, and poly(St-DVB)-SO3H+poly(St-VBC)-NH2 as the catalyst system. The optimized catalyst showed excellent catalytic performance with 100% substrate conversion and 100% yield of the final product in the one-pot production of β-nitrostyrene from benzaldehyde dimethyl acetal under cascade reactions comprising acid-catalyzed deacetalization and base-catalyzed Henry reactions. It was shown that these catalysts were reusable for up to four consecutive runs with a very slight loss of activity. The excellent performance of the catalyst was attributed to the excellent chemical and physical properties of the developed support since it provides an elegant route for preparing site-isolated acid–base dual heterogenized functional groups and preventing their deactivation via chemical neutralization.

Pulsed-sonochemiluminescence combined with molecularly imprinted polymerized high internal phase emulsion adsorbent for determination of bentazone.

A small low-power humidifier with a simple programmable on/off switch was used as a pulsed ultrasound generator. Using this tool, a novel sonochemiluminescence (SCL) method was developed to determine bentazone. To the best of our knowledge, no chemiluminescence method has been proposed to determine this pesticide. Only five studies have been proposed for SCL quantitative applications so far. Therefore, revealing new aspects of SCL promises to develop analytical methods for the quantitative determination of different substances. A molecularly imprinted polymerized high internal phase emulsion (MIP-polyHIPE) was synthesized, bentazone separated from aqueous solutions, and pre-concentrated by the MIP-polyHIPE foam. The adsorption of bentazone on the MIP-polyHIPE adsorbent was theoretically studied by density functional theory through molecular dynamics simulation. Both experimental and simulation results indicated removal and pre-concentration of bentazone by the MIP-polyHIPE adsorbent. Using the proposed SCL method and without pre-concentration process, a linear dynamic range (LDR) of 2.5 × 10-7-5.0 × 10-5mol L-1 and a limit of detection (LOD) of 8.4 × 10-8mol L-1 were obtained for bentazone with a relative standard deviation of 2.64%. The LDR and LOD were improved to 2.6 × 10-9-2.0 × 10-7mol L-1 and 8.8 × 10-10mol L-1, respectively, using MIP-polyHIPE adsorbents. The method's application was evaluated by removing and pre-concentration of bentazone from water samples, including well, river, and tap water. The results showed that the pre-concentration factor and recovery percentages were 113-131 times and 93-106%, respectively, using the MIP-polyHIPE absorbent.

3D superhydrophobic/superoleophilic sponge with hierarchical porous structure and robust stability for high-efficiency and continuous separation of oily wastewater

Three-dimensional (3D) superhydrophobic/superoleophilic polymeric materials, with highly efficient and continuous separation ability of immiscible oil/water mixtures and water-in-oil emulsions, combined with robust physical/chemical stability, are highly desirable for remediating complex oily wastewaters, but still remain a challenge to be realized. Herein, polystyrene-divinylbenzene-polydimethylsiloxane based superhydrophobic/superoleophilic foam with hierarchical porous structure was designed and prepared by high internal phase emulsion polymerization to overcome the aforementioned challenge. With hierarchical porous structure and superhydrophobic/superoleophilic properties (water/oil contact angles were 152° and 0°, respectively), the as-prepared foam could continuously separate different immiscible oil/water mixtures and water-in-oil emulsions with high separation efficiencies (>99.57 % and 99.1 %, respectively). Interestingly, our foam also displayed other properties such as stability, strong wear-resistance (the surface wettability was intact even after 100 abrasion cycles), robust anti-corrosive performance (the surface wettability and structure did not change after immersing the foam in acidic/basic/saline solutions or strongly polar organic solvents (DMF, DMSO) for a week), and broad range of temperature tolerance from −18 ℃ to 150 ℃. Due to these outstanding functions, our foam has great potential for remediation of complex oily wastewaters.

Flow injection chemiluminescence determination of ethion and computational investigation of the adsorption process on molecularly imprinted polymerized high internal phase emulsion

The lack of sufficient selectivity is the main limitation of chemiluminescence (CL) methods; because the CL reagent is not restricted to a specific analyte. This study investigated the preconcentration and determination of ethion using a flow injection CL (FIA-CL) method using a molecularly imprinted poly high internal phase emulsion (MIP-polyHIPE) adsorbent. Preliminary studies showed that ethion could be determined with high sensitivity in the Ru(bipy)3 2+ -acidic Ce(IV) CL system. A MIP-polyHIPE adsorbent was synthesized and used for preconcentration to increase the selectivity and sensitivity of the method. The adsorption of ethion on the adsorbent was investigated using density functional theory (DFT) and molecular dynamics (MD), UV-vis and FTIR spectrophotometry and liquid chromatography-tandem mass spectrometry (LC-MS-MS). Response surface methodology (RSM) and central composite design (CCD) were used to find optimized concentrations of variables. The linear dynamic range (LDR) and limit of detection (LOD) for ethion in the FIA-CL method were calculated 1.0 ⨯ 10-9 to 2.0 ⨯ 10-7 and 6.0 ⨯ 10-10 mol L-1 , respectively. The percentage of relative standard deviation for five repetitive measurements of 5.0 ⨯ 10-8 mol L-1 ethion was 4.2%. The proposed method was successfully used to separate and preconcentrate ethion from drinking and surface water sources.

PEG-in-PDMS drops stabilised by soft silicone skins as a model system for elastocapillary emulsions with explicit morphology control

HypothesisThe morphology of ordinary macro-emulsions is controlled by their high interfacial energies, i.e., by capillarity, leading to well-known structural features which can be tuned only over a narrow range. We claim here that a more explicit control over a much wider range of morphologies can be obtained by producing ”elastocapillary emulsions” in which interfacial elasticity acts simultaneously with interfacial tension. ExperimentsWe develop a model-system composed of PEG-in-PDMS emulsions, in which a catalyst diffuses from the PEG drops into the silicone matrix containing two reactive silicone polymers, which are cross-linked in a non-reactive silicone matrix to form a silicone gel of controlled thickness and mechanical properties on the drop surface. We characterise the cross-linking process of the gel in bulk and at the interface, and we analyse the skin growth kinetics. We then use the obtained understanding to produce emulsions with controlled elastocapillary interfaces using in-flow-chemistry in a purpose-designed millifluidic circuit. FindingsWe show that this approach allows to create interfaces over the full range of elastocapillary properties, and that very different emulsion morphologies can be generated depending on whether capillarity or elasticity dominates. These findings advance our fundamental understanding of the morphology of emulsions with complex interfaces, and they are of importance for the design of polymerised High Internal Phase Emulsions (polyHIPEs) with original structure/property relations. They will also be useful for the design of silicone capsules with fine-tuned mechanical properties.

Shape-stabilized n-heptadecane/polymeric foams with modified iron oxide nanoparticles for thermal energy storage

This study based on design, preparation and characterization of polymerized high internal phase emulsion (poliHIPE) foams as support materials containing iron oxide (Fe3O4) nanoparticles for impregnation of n-heptadecane as phase change material (PCM). The Fe3O4 nanoparticles were synthesized mechanically assisted co-precipitation method and modified for harmonization with the emulsion system. Fe3O4 nanoparticles doped support materials were prepared via emulsion-templated strategy, and the produced polymeric foams used for preparation of shape-stabilized n-heptadecane based composite PCMs. The total latent heat was determined as 99.6 J/g by differential scanning calorimetry (DSC) analysis, while the impregnation ratio of n-heptadecane was found to be 67%. The performances of composites were also investigated via leakage test and heat storage rate measurement. Based on the analysis result, it was determined that shape-stabilized n-heptadecane based composite PCMs are promising energy materials for low temperature latent heat storage applications.

Facile Fabrication of Superhydrophobic Graphene/Polystyrene Foams for Efficient and Continuous Separation of Immiscible and Emulsified Oil/Water Mixtures.

Three-dimensional superhydrophobic/superlipophilic porous materials have attracted widespread attention for use in the separation of oil/water mixtures. However, a simple strategy to prepare superhydrophobic porous materials capable of efficient and continuous separation of immiscible and emulsified oil/water mixtures has not yet been realized. Herein, a superhydrophobic graphene/polystyrene composite material with a micro-nanopore structure was prepared by a single-step reaction through high internal phase emulsion polymerization. Graphene was introduced into the polystyrene-based porous materials to not only enhance the flexibility of the matrix, but also increase the overall hydrophobicity of the composite materials. The resulting as-prepared monoliths had excellent mechanical properties, were superhydrophobic/superoleophilic (water/oil contact angles were 151° and 0°, respectively), and could be used to continuously separate immiscible oil/water mixtures with a separation efficiency that exceeded 99.6%. Due to the size-dependent filtration and the tortuous and lengthy micro-nano permeation paths, our foams were also able to separate surfactant-stabilized water-in-oil microemulsions. This work demonstrates a facile strategy for preparing superhydrophobic foams for the efficient and continuous separation of immiscible and emulsified oil/water mixtures, and the resulting materials have highly promising application potentials in large-scale oily wastewater treatment.

Oxygen-enriched hierarchical porous carbon supported Co-Ni nanoparticles for promising hybrid supercapacitors via one step pyrolysis of polymerized high internal phase emulsion

The urgent demand for high-performance energy storage components has been driving the exploration for superior battery-type electrode materials for hybrid supercapacitors, which is challenging but of considerable significance. In this paper, a one-step pyrolysis route was elaborated to prepare oxygen-enriched hierarchical porous carbon supported Co-Ni nanoparticles Co-Ni/OHPCs) by facile self-crosslinking assisted high internal phase emulsion (HIPE) templating. The oxygen-enriched porous carbon framework provides large specific surface area and structural stability, meanwhile Co doping can significantly reinforce the electrochemical performance of the Co-Ni/OHPCs battery-type electrodes. By optimizing the ratio of Ni2+ to Co2+ ions, the obtained Co-Ni/OHPC electrodes exhibited excellent electrochemical performance of 817.3 F g−1 at a scan rate of 5 mV s−1. Furthermore, coupling with an activated porous carbon anode, the assembled hybrid supercapacitor (HSC) possessed an appreciable energy density of 66.94 Wh kg−1 at 409.9 W kg−1 and a capacitance retention ratio of 73.89% after 5000 cycles, showing considerable application prospects. This structural design strategy provides new inspiration for the reasonable optimization of new electrode materials for promising hybrid supercapacitors.

Bifunctional imidazolium/amine polymer foams: One-pot synthesis and synergistic promotion of CO2 sorption

Amines and imidazolium are well-known functional groups in carbon dioxide capture applications because of their excellent interactions with CO2, but their combination and possible synergistic effects when combined in polymer foams have not yet been considered. This work reports an innovative one-pot water-mediated synthesis of bifunctional imidazolium/amine microcellular polymer foams containing tunable ratios of these functions by combining the Radziszewski multicomponent reaction and high internal phase emulsion (HIPE) polymerization in a one-pot manner. The resulting polymer foams have unique textural and structural properties exhibiting rapid CO2 sorption kinetics with good capacities and excellent ability to selectively capture CO2 from the gas mixture in spite of their low specific surface. The bifunctional amine/imidazolium foams showed superior CO2 capture performances compared to their monofunctional counterparts, indicating the synergy between the functional groups. Comparison with the corresponding non-porous bulk materials also proved that the imidazolium/amine bifunctionality must be incorporated in a highly porous morphology to beneficiate from efficient and fast CO2 uptake. The marked influence of both the amine/imidazolium ratio and the nature of the imidazolium counteranion on CO2 capture capacity under dry and humid conditions is demonstrated, as well as the outstanding multicyclic capture performance.

Synthesis of poly(lactic acid)-based macro-porous foams with thermo-active shape memory property via W/O high internal phase emulsion polymerization

Synthesis of poly(lactic acid)-based macro-porous foams with thermo-active shape memory property via W/O high internal phase emulsion polymerization