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Alexander Bismarck - One of the best experts on this subject based on the ideXlab platform.
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polymerised high Internal Phase emulsions for fluid separation applications
Current opinion in chemical engineering, 2014Co-Authors: Michael Tebboth, Alexander Bismarck, Angelika Menner, Andreas KogelbauerAbstract:Emulsion templated macroporous polymers, called poly(merised) high Internal Phase emulsions (polyHIPEs), are considered for a wide variety of applications ranging from supports for chemical reactions to bone grafts; however this review focuses only on applications of polyHIPEs in the field of fluid separations. PolyHIPEs are produced by polymerisation or solidification of the continuous Phase of a HIPE and removal of the Internal emulsion Phase. They possess an interconnected pore structure giving them a significant permeability. This review provides a brief overview of what polyHIPEs are and then examines their potential for fluid separation applications. So far polyHIPEs are used as filters, membranes, ion exchange columns for protein purification, chromatography, chemical scavenging, absorption and for breaking emulsions.
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macroporous polymer nanocomposites synthesised from high Internal Phase emulsion templates stabilised by reduced graphene oxide
Polymer, 2014Co-Authors: Alexander Bismarck, Angelika Menner, Ling Ching L Wong, Suelen Barg, Paula Do Vale Pereira, Goki Eda, Manish Chowalla, Eduardo SaizAbstract:Abstract Reduced graphene oxide (rGO) is known to be electrically conductive and adsorb at oil–water interfaces. It has also been shown to mechanically reinforce bulk materials. This work combines these favourable characteristics of two-dimensional rGO to develop 3D macroporous polymer nanocomposites via emulsion templating. rGO proved to be an efficient emulsifier as only 0.2 mg/ml (with respect to the oil Phase) of rGO was required to stabilise water-in-oil high Internal Phase emulsions (HIPE) of up to 80 vol.% Internal Phase. After polymerisation of the continuous minority monomer (styrene and divinylbenzene) Phase, macroporous polymer nanocomposites with tuneable microstructures were obtained. The storage modulus of rGO-poly(styrene-co-divinylbenzene) HIPEs increased by almost an order of magnitude when the rGO concentration used to stabilise the HIPE template increased from 0.4 to 5.0 mg/ml. The adsorption and organisation of rGO at the o/w interface in HIPEs prior to polymerisation and partial aggregation in the polymer cell walls after polymerisation resulted in conductive nanocomposites with a rGO content of as low as 0.006 vol.% (with respect to bulk polymer volume or 0.8 mg/ml with respect to the monomer volume used in the emulsion template) compared to 0.1 vol.% for dense nanocomposites previously reported. This provided evidence for the efficient arrangement of rGO within the macroporous polymer nanocomposite, creating an electrically conductive network.
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polymerised high Internal Phase ionic liquid in oil emulsions as potential separators for lithium ion batteries
Journal of Materials Chemistry, 2013Co-Authors: Natasha Shirshova, Alexander Bismarck, Patrik Johansson, Maciej J Marczewski, David Ensling, Joachim H G SteinkeAbstract:In situ ionic liquid (IL) filled poly(merized) high Internal Phase emulsion monoliths and films were produced by polymerizing surfactant stabilized IL/monomer emulsion templates. The resulting in situ ionic liquid filled macroporous polymers have almost the ionic conductivity of the neat ionic liquid electrolyte. The effect of surfactant and lithium salt concentration, monomer to crosslinker ratio as well as Internal Phase volume ratio on the morphology and ionic conductivity were studied. It was found that the morphology of the resulting polyHIPEs affects significantly their ionic conductivity. PolyHIPEs with bigger pore throats have a higher ionic conductivity.
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hierarchical polymerized high Internal Phase emulsions synthesized from surfactant stabilized emulsion templates
Langmuir, 2013Co-Authors: Ling L C Wong, Angelika Menner, Pedro Baiz M Villafranca, Alexander BismarckAbstract:In building construction, structural elements, such as lattice girders, are positioned specifically to support the mainframe of a building. This arrangement provides additional structural hierarchy, facilitating the transfer of load to its foundation while keeping the building weight down. We applied the same concept when synthesizing hierarchical open-celled macroporous polymers from high Internal Phase emulsion (HIPE) templates stabilized by varying concentrations of a polymeric non-ionic surfactant from 0.75 to 20 w/vol %. These hierarchical poly(merized)HIPEs have multimodally distributed pores, which are efficiently arranged to enhance the load transfer mechanism in the polymer foam. As a result, hierarchical polyHIPEs produced from HIPEs stabilized by 5 vol % surfactant showed a 93% improvement in Young’s moduli compared to conventional polyHIPEs produced from HIPEs stabilized by 20 vol % of surfactant with the same porosity of 84%. The finite element method (FEM) was used to determine the effect of...
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interconnected macroporous glycidyl methacrylate grafted dextran hydrogels synthesised from hydroxyapatite nanoparticle stabilised high Internal Phase emulsion templates
Journal of Materials Chemistry, 2012Co-Authors: Shengzhong Zhou, Alexander Bismarck, Joachim H G SteinkeAbstract:Commercially available hydroxyapatite (HAp) nanoparticles were used as sole emulsifiers to produce stable methyl myristate-in-water and soybean oil-in-water high Internal Phase emulsions (HIPEs). The droplet size in the Pickering inverse HIPEs (i-HIPEs) could be adjusted within a certain range by tailoring the energy input during emulsification and emulsifier concentrations. These HAp nanoparticle stabilised i-HIPEs were then used as templates to synthesise interconnected high porosity macroporous hydrogels by crosslinking glycidyl methacrylate (GMA) functionalised dextran, which was dissolved in the continuous aqueous Phase of the i-HIPEs. The pore size of these polyPickering-HIPE hydrogels could be adjusted by the emulsifier concentration, oil type, emulsification conditions or ripening time of the i-HIPE templates.
Xiao-quan Yang - One of the best experts on this subject based on the ideXlab platform.
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Facile and Robust Route for Preparing Pickering High Internal Phase Emulsions Stabilized by Bare Zein Particles
'American Chemical Society (ACS)', 2021Co-Authors: Fuzhen Zhou, Shouwei Yin, Dong-hui Luo, Bo Liu, Tao Yang, Xiao-quan YangAbstract:Pickering high Internal Phase emulsions (HIPEs) stabilized by biological particles have attracted growing interest. However, developing Pickering HIPEs with bare zein particles (ZPs) is still a challenge. Here, we demonstrated a facile method for the development of Pickering HIPEs stabilized solely by bare ZPs. In brief, the pH value was adjusted during the emulsification; thus, the aggregation of ZPs transferred from the continuous Phase of HIPEs to the oil–water interface. In detail, the strong hydrophobicity of ZPs was changed into intermediate wettability after changing pH, as indicated by the value of the three-Phase contact angle (θ) decreasing from 108.4° to around 90°. Through adjusting the assembly behaviors of ZPs, the interfacial and continuous microstructures in the emulsification system were defined accordingly, therefore forming stable Pickering HIPEs. Generally, with the final NaOH concentration ranging from 0.6 to 2.0 mM in HIPEs (pH 6.6–8.9), HIPEs with an Internal Phase volume fraction of 80% were prepared successfully using pristine ZPs as sole eco-friendly Pickering stabilizers. The microstructure of HIPEs featured that ZPs deposited in situ at the oil–water interface, forming an effective physical barrier, while the rest of ZPs that remained in water Phase functioned as the structural element and stacked into a 3D network architecture, constituting another strong barrier and facilitating the immobilization of oil droplets. This microstructure contributed to satisfactory stability, good viscoelasticity behavior, and ideal thixotropic recovery of HIPEs. Moreover, the HIPEs obtained here served as the encapsulation system for probiotics, and they maintained the viability of Lactobacillus plantarum at 4 °C. The facile method developed here paves the way for preparing Pickering HIPEs stabilized by protein-based particles
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fabrication of zein pectin hybrid particle stabilized pickering high Internal Phase emulsions with robust and ordered interface architecture
Journal of Agricultural and Food Chemistry, 2018Co-Authors: Fuzhen Zhou, Xiaonan Huang, Shouwei Yin, Jianhua Zhu, Chuanhe Tang, Xiao-quan YangAbstract:Diets containing partially hydrogenated oils (PHOs) expose the human body to trans fatty acids, thus endangering cardiovascular health. Pickering high Internal Phase emulsions (HIPEs) is a promisin...
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fabrication of zein pectin hybrid particle stabilized pickering high Internal Phase emulsions with robust and ordered interface architecture
Journal of Agricultural and Food Chemistry, 2018Co-Authors: Fuzhen Zhou, Xiaonan Huang, Chuanhe Tang, Ziling Wu, Xiao-quan YangAbstract:Diets containing partially hydrogenated oils (PHOs) expose the human body to trans fatty acids, thus endangering cardiovascular health. Pickering high Internal Phase emulsions (HIPEs) is a promising alternative of PHOs. This work attempted to construct stable Pickering HIPEs by engineering interface architecture through manipulating the interfacial, self-assembly, and packing behavior of zein particles using the interaction between protein and pectin. Partially wettable zein/pectin hybrid particles (ZPHPs) with three-Phase contact angles ranging from 84° to 87° were developed successfully. ZPHPs were irreversibly anchored at the oil–water interface, resulting in robust and ordered interfacial structure, evidenced by the combination of LB-SEM and CLSM. This situation helped to hold a percolating 3D oil droplet network, which facilitated the formation of Pickering HIPEs with viscoelasticity, excellent thixotropy (>91.0%), and storage stability. Curcumin in HIPEs was well protected from UV-induced degradatio...
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fabrication of zein pectin hybrid particle stabilized pickering high Internal Phase emulsions with robust and ordered interface architecture
Journal of Agricultural and Food Chemistry, 2018Co-Authors: Fuzhen Zhou, Xiaonan Huang, Shouwei Yin, Jianhua Zhu, Chuanhe Tang, Xiao-quan YangAbstract:Diets containing partially hydrogenated oils (PHOs) expose the human body to trans fatty acids, thus endangering cardiovascular health. Pickering high Internal Phase emulsions (HIPEs) is a promising alternative of PHOs. This work attempted to construct stable Pickering HIPEs by engineering interface architecture through manipulating the interfacial, self-assembly, and packing behavior of zein particles using the interaction between protein and pectin. Partially wettable zein/pectin hybrid particles (ZPHPs) with three-Phase contact angles ranging from 84° to 87° were developed successfully. ZPHPs were irreversibly anchored at the oil-water interface, resulting in robust and ordered interfacial structure, evidenced by the combination of LB-SEM and CLSM. This situation helped to hold a percolating 3D oil droplet network, which facilitated the formation of Pickering HIPEs with viscoelasticity, excellent thixotropy (>91.0%), and storage stability. Curcumin in HIPEs was well protected from UV-induced degradation and endowed HIPEs with ideal oxidant stability. Fabricated Pickering HIPEs possess a charming application prospect in foods and the pharmaceutical industry.
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Wheat gluten-stabilized high Internal Phase emulsions as mayonnaise replacers
Food Hydrocolloids, 2018Co-Authors: Xiao Liu, Zhi Li Wan, Qi Jun Ruan, Yu-yang Liu, Jian Guo, Xiao-quan YangAbstract:Plant protein-based diets (e.g., egg or meat alternatives) have emerged as a promising approach for developing healthy and sustainable food systems. Mayonnaise, a formulated sauce prepared by mixing vegetable oil, egg yolk, vinegar and salt, is probably one of the most widely used condiments in the world today. In this paper, wheat gluten (WG) as an available and low-cost plant protein ingredient was used to prepare and stabilize oil-in-water high Internal Phase emulsions (HIPEs) as mayonnaise replacers via emulsification–evaporation method. Firstly, WG was dissolved into aqueous acetic acid/ethanol (55/45, v/v, pH 3.0) solution to form Phase-separated WG particles, and then HIPEs were prepared through homogenization of high sunflower oil fraction (75 wt%) with WG particles suspension at 80 °C after evaporating ethanol completely. Compared with egg-based mayonnaise, HIPEs (especially for 1.0 wt% WG) exhibited very similar droplet size distribution, rheological behavior, near-perfect thixotropic recovery, and tribological property. These results demonstrated that HIPEs and mayonnaise might have similar sensory property and perceived texture such as creaminess, smoothness, and sliminess. The confocal laser scanning microscopy (CLSM) indicated that close-packed oil droplets could allow them to form homogeneous oil-in-protein network microstructure in HIPEs and mayonnaise, which might contribute to high viscoelasticity, consistency, and correct texture. In addition, thermal stability of HIPEs was much better than that of the mayonnaise. Design and construction of WG-stabilized oil-in-water HIPEs may provide a potential strategy for preparing mayonnaise replacers.
Haitao Wang - One of the best experts on this subject based on the ideXlab platform.
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interconnectivity of macroporous hydrogels prepared via graphene oxide stabilized pickering high Internal Phase emulsions
Langmuir, 2016Co-Authors: Haitao WangAbstract:Interconnected macroporous poly(acrylic acid) (PAA) hydrogels are prepared via oil-in-water (o/w) Pickering high Internal Phase emulsion (HIPE) templates stabilized by graphene oxide (GO). The amphiphilicity of GO is adjusted by slight modification with cetyltrimethylammonium bromide (CTAB). The morphology of macroporous PAA is observed by a field-emission scanning electron microscope (FE-SEM). The gas permeability is characterized to evaluate the interconnectivity of polymer foams. The pore and pore throat size can be tailored by varying the wettability and concentration of GO. The selective adsorption toward dyes of PAA hydrogels is proved. Macroporous PAA hydrogels with an open-cell structure show enhanced adsorption behavior of both methylene blue (MB) and copper(II) ions.
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interconnected macroporous polymers synthesized from silica particle stabilized high Internal Phase emulsions
Macromolecules, 2014Co-Authors: Xianhua Zheng, Yi Zhang, Haitao WangAbstract:n-Octadecyltrimethoxysilane (ODS)-modified silica particles were used as sole Pickering stabilizer to prepare water-in-oil Pickering high Internal Phase emulsions (HIPEs) with an Internal Phase volume of 80%. After polymerization of the continuous Phase of HIPEs, interconnected macroporous polymers were obtained when modified silica was initially dispersed in water to form a micelle-like structure. However, silica particles in oil Phase resulted in closed-cell pores. The pore size, the pore wall morphology, and the interconnectivity of polymer foams could be adjusted finely by the grafted amounts of ODS, modified silica concentrations, and the initial location of Pickering stabilizer. The gas permeation of interconnected porous polymers increased dramatically with the increase of the hydrophobicity of silica particles from 3 to 153 mL/min.
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macroporous graphene oxide polymer composite prepared through pickering high Internal Phase emulsions
ACS Applied Materials & Interfaces, 2013Co-Authors: Zheng Zheng, Xianhua Zheng, Haitao WangAbstract:Macroporous polymer–graphene oxide (GO) composites were successfully prepared using Pickering high Internal Phase emulsion (HIPE) templates. GO flakes were modified by the cationic surfactant cetyltrimethylammonium bromide (CTAB) and used as the stabilizer of water-in-oil (W/O) Pickering emulsions. CTAB-modified GO is effective at stabilizing W/O Pickering HIPEs, and the lowest GO content is only about 0.2 mg mL–1 (relative to the volume of the oil Phase). The close-cell morphology of the resulting poly-Pickering HIPEs is observed, and the void size of the porous polymers is tuned by varying the concentration of GO. Three-dimensional macroporous chemically modified graphene (CMG) monoliths with a high specific surface area of about 490 m2 g–1 were obtained after removing the cellular polymer substrates through calcination. The micropores were also found in CMGs, which may be caused by the decomposition of CTAB adsorbed on the surface of GO.
To Ngai - One of the best experts on this subject based on the ideXlab platform.
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hierarchical porous protein scaffold templated from high Internal Phase emulsion costabilized by gelatin and gelatin nanoparticles
Langmuir, 2018Co-Authors: Huan Tan, Hongqian Jia, Xiaojun Gou, To NgaiAbstract:Recently, three-dimensional (3D) scaffolds produced using poly-Pickering high Internal Phase emulsions (polyHIPEs) technology are particularly attractive in biomedical application. However, until now the most investigated polyHIPEs are hydrophobic composites originating from synthetic polymers. Here we present an investigation of a hierarchical porous protein scaffold templated from oil-in-water (O/W) HIPEs costabilized by fully natural materials, gelatin, and gelatin nanoparticles. Fairly monodispersed gelatin nanoparticles were first synthesized through a two-step desolvation method, and then they were used as emulsifiers together with gelatin to fabricate stable HIPEs with adjustable droplet size distribution and rheology. Monolithic scaffolds were formed by cross-linking the HIPEs with polymers as low as 2.5 wt % in the continuous Phase, which appropriately presented a general high porosity and had an interconnected porous morphology with smooth pore walls and textured structures. Furthermore, the sca...
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gelatin particle stabilized high Internal Phase emulsions for use in oral delivery systems protection effect and in vitro digestion study
Journal of Agricultural and Food Chemistry, 2017Co-Authors: Huan Tan, Xiaojun Gou, Lifeng Zhao, Sisi Tian, Hui Wen, To NgaiAbstract:The potential application of Pickering high-Internal Phase emulsions (HIPEs) in the food and pharmaceutical industries has yet to be fully developed. Herein, we synthesized fairly monodisperse, nontoxic, autofluorescent gelatin particles for use as sole stabilizers for fabricating oil-in-water (O/W) HIPEs in an effort to improve the protection and bioaccessibility of entrapped β-carotene. Our results showed that the concentration of gelatin particles determined the formation, microstructure, droplet size distribution, and digestion profile of the HIPEs. For storage stability, the retention of β-carotene in HIPEs was significantly higher than in dispersion in bulk oil, even after storage for 27 days. In addition, in vitro digestion experiments indicated that the bioaccessibility of β-carotene was improved 5-fold in HIPEs. This study will help establish a correlation between the physicochemical properties of gelatin particle-stabilized HIPEs with their applications in the oral delivery of bioactive nutraceu...
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gelatin particle stabilized high Internal Phase emulsions as nutraceutical containers
ACS Applied Materials & Interfaces, 2014Co-Authors: Changdao Mu, To NgaiAbstract:In this paper, we report for the first time the use of a well-dispersed gelatin particle as a representative of natural and biocompatible materials to be an effective particle stabilizer for high Internal Phase emulsion (HIPE) formulation. Fairly monodispersed gelatin particles (∼200 nm) were synthesized through a two-step desolvation method and characterized by dynamic light scattering, ζ-potential measurements, scanning electron microscopy, and atomic force microscopy. Those protein latexes were then used as sole emulsifiers to fabricate stable oil-in-water Pickering HIPEs at different concentrations, pH conditions, and homogenization times. Most of the gelatin particles were irreversibly adsorbed at the oil–water interface to hinder droplet coalescence, such that Pickering HIPEs can be formed by a small amount of gelatin particles (as low as 0.5 wt % in the water Phase) at pH far away from the isoelectric point of the gelatin particles. In addition, increasing homogenization time led to narrow size dis...
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gelatin particle stabilized high Internal Phase emulsions as nutraceutical containers
ACS Applied Materials & Interfaces, 2014Co-Authors: Huan Tan, Guanqing Sun, Wei Lin, To NgaiAbstract:In this paper, we report for the first time the use of a well-dispersed gelatin particle as a representative of natural and biocompatible materials to be an effective particle stabilizer for high Internal Phase emulsion (HIPE) formulation. Fairly monodispersed gelatin particles (∼200 nm) were synthesized through a two-step desolvation method and characterized by dynamic light scattering, ζ-potential measurements, scanning electron microscopy, and atomic force microscopy. Those protein latexes were then used as sole emulsifiers to fabricate stable oil-in-water Pickering HIPEs at different concentrations, pH conditions, and homogenization times. Most of the gelatin particles were irreversibly adsorbed at the oil-water interface to hinder droplet coalescence, such that Pickering HIPEs can be formed by a small amount of gelatin particles (as low as 0.5 wt % in the water Phase) at pH far away from the isoelectric point of the gelatin particles. In addition, increasing homogenization time led to narrow size distribution of droplets, and high particle concentration resulted in more solidlike Pickering HIPEs. In vitro controlled-release experiments revealed that the release of the encapsulated β-carotene can be tuned by manipulating the concentration of gelatin particles in the formulation, suggesting that the stable and narrow-size-distributed gelatin-stabilized HIPEs had potential in functional food and pharmaceutical applications.
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porous tio2 materials through pickering high Internal Phase emulsion templating
Langmuir, 2014Co-Authors: Guanqing Sun, To NgaiAbstract:We report a facile method for preparing porous structured TiO2 materials by templating from Pickering high-Internal Phase emulsions (HIPEs). A Pickering HIPE with an Internal Phase of up to 80 vol %, stabilized by poly(N-isopropylacrylamide)-based microgels and TiO2 solid nanoparticles, was first formulated and employed as a template to prepare the porous TiO2 materials with an interconnected structure. The resultant materials were characterized by scanning electron microscopy, X-ray diffraction, and mercury intrusion. Our results showed that the parent emulsion droplets promoted the formation of macropores and interconnecting throats with sizes of similar to 50 and similar to 10 mu m, respectively, while the interfacially adsorbed microgel stabilizers drove the formation of smaller pores (similar to 100 nm) throughout the macroporous walls after drying and sintering. The interconnected structured network with the bimodal pores could be well preserved after calcinations at 800 degrees C. In addition, the photocatalytic activity of the fabricated TiO2 was evaluated by measuring the photodegradation of Rhodamine B in water. Our results revealed that the fabricated TiO2 materials are good photocatalysts, showing enhanced activity and stability in photodegrading organic molecules.
Angelika Menner - One of the best experts on this subject based on the ideXlab platform.
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polymerised high Internal Phase emulsions for fluid separation applications
Current opinion in chemical engineering, 2014Co-Authors: Michael Tebboth, Alexander Bismarck, Angelika Menner, Andreas KogelbauerAbstract:Emulsion templated macroporous polymers, called poly(merised) high Internal Phase emulsions (polyHIPEs), are considered for a wide variety of applications ranging from supports for chemical reactions to bone grafts; however this review focuses only on applications of polyHIPEs in the field of fluid separations. PolyHIPEs are produced by polymerisation or solidification of the continuous Phase of a HIPE and removal of the Internal emulsion Phase. They possess an interconnected pore structure giving them a significant permeability. This review provides a brief overview of what polyHIPEs are and then examines their potential for fluid separation applications. So far polyHIPEs are used as filters, membranes, ion exchange columns for protein purification, chromatography, chemical scavenging, absorption and for breaking emulsions.
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macroporous polymer nanocomposites synthesised from high Internal Phase emulsion templates stabilised by reduced graphene oxide
Polymer, 2014Co-Authors: Alexander Bismarck, Angelika Menner, Ling Ching L Wong, Suelen Barg, Paula Do Vale Pereira, Goki Eda, Manish Chowalla, Eduardo SaizAbstract:Abstract Reduced graphene oxide (rGO) is known to be electrically conductive and adsorb at oil–water interfaces. It has also been shown to mechanically reinforce bulk materials. This work combines these favourable characteristics of two-dimensional rGO to develop 3D macroporous polymer nanocomposites via emulsion templating. rGO proved to be an efficient emulsifier as only 0.2 mg/ml (with respect to the oil Phase) of rGO was required to stabilise water-in-oil high Internal Phase emulsions (HIPE) of up to 80 vol.% Internal Phase. After polymerisation of the continuous minority monomer (styrene and divinylbenzene) Phase, macroporous polymer nanocomposites with tuneable microstructures were obtained. The storage modulus of rGO-poly(styrene-co-divinylbenzene) HIPEs increased by almost an order of magnitude when the rGO concentration used to stabilise the HIPE template increased from 0.4 to 5.0 mg/ml. The adsorption and organisation of rGO at the o/w interface in HIPEs prior to polymerisation and partial aggregation in the polymer cell walls after polymerisation resulted in conductive nanocomposites with a rGO content of as low as 0.006 vol.% (with respect to bulk polymer volume or 0.8 mg/ml with respect to the monomer volume used in the emulsion template) compared to 0.1 vol.% for dense nanocomposites previously reported. This provided evidence for the efficient arrangement of rGO within the macroporous polymer nanocomposite, creating an electrically conductive network.
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hierarchical polymerized high Internal Phase emulsions synthesized from surfactant stabilized emulsion templates
Langmuir, 2013Co-Authors: Ling L C Wong, Angelika Menner, Pedro Baiz M Villafranca, Alexander BismarckAbstract:In building construction, structural elements, such as lattice girders, are positioned specifically to support the mainframe of a building. This arrangement provides additional structural hierarchy, facilitating the transfer of load to its foundation while keeping the building weight down. We applied the same concept when synthesizing hierarchical open-celled macroporous polymers from high Internal Phase emulsion (HIPE) templates stabilized by varying concentrations of a polymeric non-ionic surfactant from 0.75 to 20 w/vol %. These hierarchical poly(merized)HIPEs have multimodally distributed pores, which are efficiently arranged to enhance the load transfer mechanism in the polymer foam. As a result, hierarchical polyHIPEs produced from HIPEs stabilized by 5 vol % surfactant showed a 93% improvement in Young’s moduli compared to conventional polyHIPEs produced from HIPEs stabilized by 20 vol % of surfactant with the same porosity of 84%. The finite element method (FEM) was used to determine the effect of...
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polymerised high Internal Phase emulsion cement hybrids macroporous polymer scaffolds for setting cements
Cement and Concrete Research, 2011Co-Authors: Natasha Shirshova, Angelika Menner, Gary P Funkhouser, Alexander BismarckAbstract:We polymerised the continuous styrene/divinylbenzene monomer Phase of high Internal Phase emulsions (HIPEs) containing 70 vol.% cement slurry as Internal Phase to synthesise polymer cement hybrid materials. These novel cement containing poly(merised)HIPEs have an interconnected bi-phasic structure consisting of an interpenetrating network of set cement and polymer. Incorporating 14 wt.% of polymer into the cement resulted in an increased compressive strain to failure as compared to pure set cement but both elastic modulus and crush strength decreased. These novel polymer cement hybrid materials have a better chemical resistance against acetic acid then pure cement and showed also no shrinkage when exposed to xylene and dodecane.
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high porosity macroporous polymers sythesized from titania particle stabilized medium and high Internal Phase emulsions
Langmuir, 2010Co-Authors: Vivian O Ikem, Angelika Menner, Alexander BismarckAbstract:Particle-stabilized high Internal Phase emulsions have been used to synthesize tough and very high porosity macroporus polymers with a closed-cell pore structure. In this study, we show that Pickering water-in-oil emulsion templates with up to an 85 vol % Internal Phase can be stabilized by only 1 wt % of titania particles with their surfaces suitably modified by the adsorption of 3.5 ± 0.5 wt % oleic acid. The pore structure and mechanical properties of the resulting macroporous polymers were tailored by altering the Internal Phase volume ratio of the emulsion template and the titania particle concentration used to stabilize the emulsion templates. The pore size and pore size distributions increase with increasing Internal Phase volume of the emulsion template as well as decreasing titania particle concentration used to stabilize the emulsion template. The mechanical properties, namely, Young’s modulus and the crush strength of the macroporous polymers, increased with decreasing porosity and increasing f...