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Jean M J Frechet - One of the best experts on this subject based on the ideXlab platform.
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preparation of Porous Polymer monoliths featuring enhanced surface coverage with gold nanoparticles
Journal of Chromatography A, 2012Co-Authors: Fernando Maya Alejandro, Jean M J Frechet, Frantisek SvecAbstract:A new approach to the preparation of Porous Polymer monoliths with enhanced coverage of pore surface with gold nanoparticles has been developed. First, a generic poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith was reacted with cystamine followed by the cleavage of its disulfide bonds with tris(2-carboxylethyl)phosphine, which liberated the desired thiol groups. Dispersions of gold nanoparticles with sizes varying from 5 to 40 nm were then pumped through the functionalized monoliths. The materials were then analyzed using both energy dispersive X-ray spectroscopy and thermogravimetric analysis. We found that the quantity of attached gold was dependent on the size of nanoparticles, with the maximum attachment of more than 60 wt% being achieved with 40 nm nanoparticles. Scanning electron micrographs of the cross sections of all the monoliths revealed the formation of a non-aggregated, homogenous monolayer of nanoparticles. The surface of the bound gold was functionalized with 1-octanethiol and 1-octadecanethiol, and these monolithic columns were used successfully for the separations of proteins in reversed phase mode. The best separations were obtained using monoliths modified with 15, 20, and 30 nm nanoparticles since these sizes produced the most dense coverage of pore surface with gold.
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Porous Polymer monoliths functionalized through coPolymerization of a c60 fullerene containing methacrylate monomer for highly efficient separations of small molecules
Analytical Chemistry, 2011Co-Authors: Stuart D Chambers, Frantisek Svec, Thomas W Holcombe, Jean M J FrechetAbstract:Monolithic poly(glycidyl methacrylate-co-ethylene dimethacrylate) and poly(butyl methacrylate-co-ethylene dimethacrylate) capillary columns, which incorporate the new monomer [6,6]-phenyl-C61-butyric acid 2-hydroxyethyl methacrylate ester, have been prepared and their chromatographic performance have been tested for the separation of small molecules in the reversed phase. While addition of the C60-fullerene monomer to the glycidyl methacrylate-based monolith enhanced column efficiency 18-fold, to 85 000 plates/m at a linear velocity of 0.46 mm/s and a retention factor of 2.6, when compared to the parent monolith, the use of butyl methacrylate together with the carbon nanostructured monomer afforded monolithic columns with an efficiency for benzene exceeding 110 000 plates/m at a linear velocity of 0.32 mm/s and a retention factor of 4.2. This high efficiency is unprecedented for separations using Porous Polymer monoliths operating in an isocratic mode. Optimization of the chromatographic parameters afford...
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Porous Polymer monolithic column with surface bound gold nanoparticles for the capture and separation of cysteine containing peptides
Analytical Chemistry, 2010Co-Authors: Qing Cao, Frantisek Svec, Jean M J FrechetAbstract:A new Porous Polymer monolithic capillary column modified with gold nanoparticles that enables the selective capture of cysteine-containing peptides has been developed to reduce the complexity of peptide mixtures generated in bottom-up proteomic analysis. The column is prepared from a poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith through reaction of some of its epoxide moieties with cysteamine to afford a monolith rich in surface thiol groups. In situ reduction of chloroauric acid within the column is then used to form gold nanoparticles attached to the surface of the pores of the monolith. This process preserves the excellent hydrodynamic properties of the monolithic column while providing a means to selectively retain cysteine-containing peptides from an analyte due to their high affinity for gold. Release of the retained peptides is subsequently achieved with an excess of 2-mercaptoethanol. The loading capacity determined for l-cysteine using frontal elution is 2.58 μmol/m. Since the ...
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Porous Polymer coatings a versatile approach to superhydrophobic surfaces
Advanced Functional Materials, 2009Co-Authors: Pavel A Levkin, Frantisek Svec, Jean M J FrechetAbstract:Here, a facile and inexpensive approach to superhydrophobic Polymer coatings is presented. The method involves the in situ Polymerization of common monomers in the presence of a porogenic solvent to afford superhydrophobic surfaces with the desired combination of micro- and nanoscale roughness. The method is applicable to a variety of substrates and is not limited to small areas or flat surfaces. The Polymerized material can be ground into a superhydrophobic powder, which, once applied to a surface, renders it superhydrophobic. The morphology of the Porous Polymer structure can be efficiently controlled by composition of the Polymerization mixture, while surface chemistry can be adjusted by photografting. Morphology control is used to reduce the globule size of the Porous architecture from micro down to nanoscale thereby affording a transparent material. The influence of both surface chemistry as well as the length scale of surface roughness on the superhydrophobicity is discussed.
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fabrication of Porous Polymer monoliths covalently attached to the walls of channels in plastic microdevices
Electrophoresis, 2003Co-Authors: Timothy B Stachowiak, Frantisek Svec, Jean M J Frechet, Thomas Rohr, Emily F Hilder, Dominic S PetersonAbstract:UV-initiated grafting of plastic tubes and microfluidic chips with ethylene diacrylate followed by the preparation of Porous Polymer monoliths has been studied. The first step affords a thin grafted layer of Polymer with a multiplicity of pendent double bonds that are then used in the second step for covalent attachment of the monolith to the wall. As clearly seen on scanning electron micrographs, this procedure prevents the formation of voids at the monolith-channel interface a problem that has always plagued approaches involving bulk Polymerization in nontreated channels due to the shrinkage of the monolith during the Polymerization process and its lack of compatibility with the material of the device. Irradiation with UV light through a photomask allows precise patterning specifying both the area subjected to surface modification and the location of the monolith within specific areas of the device.
Frantisek Svec - One of the best experts on this subject based on the ideXlab platform.
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preparation of Porous Polymer monoliths featuring enhanced surface coverage with gold nanoparticles
Journal of Chromatography A, 2012Co-Authors: Fernando Maya Alejandro, Jean M J Frechet, Frantisek SvecAbstract:A new approach to the preparation of Porous Polymer monoliths with enhanced coverage of pore surface with gold nanoparticles has been developed. First, a generic poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith was reacted with cystamine followed by the cleavage of its disulfide bonds with tris(2-carboxylethyl)phosphine, which liberated the desired thiol groups. Dispersions of gold nanoparticles with sizes varying from 5 to 40 nm were then pumped through the functionalized monoliths. The materials were then analyzed using both energy dispersive X-ray spectroscopy and thermogravimetric analysis. We found that the quantity of attached gold was dependent on the size of nanoparticles, with the maximum attachment of more than 60 wt% being achieved with 40 nm nanoparticles. Scanning electron micrographs of the cross sections of all the monoliths revealed the formation of a non-aggregated, homogenous monolayer of nanoparticles. The surface of the bound gold was functionalized with 1-octanethiol and 1-octadecanethiol, and these monolithic columns were used successfully for the separations of proteins in reversed phase mode. The best separations were obtained using monoliths modified with 15, 20, and 30 nm nanoparticles since these sizes produced the most dense coverage of pore surface with gold.
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thiol ene click chemistry a facile and versatile route for the functionalization of Porous Polymer monoliths
Analyst, 2012Co-Authors: Zhixing Lin, Frantisek SvecAbstract:The preparation of Porous Polymer monoliths with dodecyl and zwitterionic functionalities via the “thiol–ene” click chemistry of thiol-containing monoliths with both hydrophobic and polar methacrylate “ene” monomers has been demonstrated. Selected separations confirmed the excellent potential of these monoliths in chromatography.
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Porous Polymer monoliths functionalized through coPolymerization of a c60 fullerene containing methacrylate monomer for highly efficient separations of small molecules
Analytical Chemistry, 2011Co-Authors: Stuart D Chambers, Frantisek Svec, Thomas W Holcombe, Jean M J FrechetAbstract:Monolithic poly(glycidyl methacrylate-co-ethylene dimethacrylate) and poly(butyl methacrylate-co-ethylene dimethacrylate) capillary columns, which incorporate the new monomer [6,6]-phenyl-C61-butyric acid 2-hydroxyethyl methacrylate ester, have been prepared and their chromatographic performance have been tested for the separation of small molecules in the reversed phase. While addition of the C60-fullerene monomer to the glycidyl methacrylate-based monolith enhanced column efficiency 18-fold, to 85 000 plates/m at a linear velocity of 0.46 mm/s and a retention factor of 2.6, when compared to the parent monolith, the use of butyl methacrylate together with the carbon nanostructured monomer afforded monolithic columns with an efficiency for benzene exceeding 110 000 plates/m at a linear velocity of 0.32 mm/s and a retention factor of 4.2. This high efficiency is unprecedented for separations using Porous Polymer monoliths operating in an isocratic mode. Optimization of the chromatographic parameters afford...
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Porous Polymer monolithic column with surface bound gold nanoparticles for the capture and separation of cysteine containing peptides
Analytical Chemistry, 2010Co-Authors: Qing Cao, Frantisek Svec, Jean M J FrechetAbstract:A new Porous Polymer monolithic capillary column modified with gold nanoparticles that enables the selective capture of cysteine-containing peptides has been developed to reduce the complexity of peptide mixtures generated in bottom-up proteomic analysis. The column is prepared from a poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith through reaction of some of its epoxide moieties with cysteamine to afford a monolith rich in surface thiol groups. In situ reduction of chloroauric acid within the column is then used to form gold nanoparticles attached to the surface of the pores of the monolith. This process preserves the excellent hydrodynamic properties of the monolithic column while providing a means to selectively retain cysteine-containing peptides from an analyte due to their high affinity for gold. Release of the retained peptides is subsequently achieved with an excess of 2-mercaptoethanol. The loading capacity determined for l-cysteine using frontal elution is 2.58 μmol/m. Since the ...
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Porous Polymer monoliths amazingly wide variety of techniques enabling their preparation
Journal of Chromatography A, 2010Co-Authors: Frantisek SvecAbstract:Abstract The Porous Polymer monoliths went a long way since their invention two decades ago. While the first studies applied the traditional Polymerization processes at that time well established for the preparation of Polymer particles, creativity of scientists interested in the monolithic structures has later led to the use of numerous less common techniques. This review article presents vast variety of methods that have meanwhile emerged. The text first briefly describes the early approaches used for the preparation of monoliths comprising standard free radical Polymerizations and includes their development up to present days. Specific attention is paid to the effects of process variables on the formation of both Porous structure and pore surface chemistry. Specific attention is also devoted to the use of photoPolymerization. Then, several less common free radical Polymerization techniques are presented in more detail such as those initiated by γ-rays and electron beam, the preparation of monoliths from high internal phase emulsions, and cryogels. Living processes including stable free radicals, atom transfer radical Polymerization, and ring-opening metathesis Polymerization are also discussed. The review ends with description of preparation methods based on polycondensation and polyaddition reactions as well as on precipitation of preformed Polymers affording the monolithic materials.
Hongcai Zhou - One of the best experts on this subject based on the ideXlab platform.
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stable benzimidazole incorporated Porous Polymer network for carbon capture with high efficiency and low cost
Polymer, 2014Co-Authors: Muwei Zhang, Zachary Perry, Jinhee Park, Hongcai ZhouAbstract:Abstract Porous Polymer Networks (PPNs) are an emerging category of advanced Porous materials that are of interest for carbon dioxide capture due to their great stabilities and convenient functionalization processes. In this work, an intrinsically-functionalized Porous network, PPN-101, was prepared from commercially accessible materials via an easy two-step synthesis. It has a BET surface area of 1095 m2/g. Due to the presence of the benzimidazole units in the framework, its CO2 uptake at 273 K reaches 115 cm3/g and its calculated CO2/N2 selectivity is 199, which indicates its potential for CO2/N2 separation. The great stability, large CO2/N2 selectivity and low production cost make PPN-101 a promising material for industrial separation of CO2 from flue gas. Its H2 and CH4 uptake properties were also investigated.
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polyamine tethered Porous Polymer networks for carbon dioxide capture from flue gas
Angewandte Chemie, 2012Co-Authors: Julian P Sculley, Daqiang Yuan, R Krishna, Zhangwen Wei, Hongcai ZhouAbstract:Gas guzzler: The introduction of polyamines in Porous Polymer networks results in significant enhancement of CO2‐uptake capacities at low pressures. The best substituted network was found to exhibit high adsorption enthalpies for CO2 and the largest selectivity (see graph) of any Porous material reported to date. It also had outstanding physicochemical stability and could be regenerated under mild conditions.
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sulfonate grafted Porous Polymer networks for preferential co2 adsorption at low pressure
Journal of the American Chemical Society, 2011Co-Authors: Daqiang Yuan, Julian P Sculley, R Krishna, Dan Zhao, Hongcai ZhouAbstract:A Porous Polymer network (PPN) grafted with sulfonic acid (PPN-6-SO3H) and its lithium salt (PPN-6-SO3Li) exhibit significant increases in isosteric heats of CO2 adsorption and CO2-uptake capacities. IAST calculations using single-component-isotherm data and a 15/85 CO2/N2 ratio at 295 K and 1 bar revealed that the sulfonate-grafted PPN-6 networks show exceptionally high adsorption selectivity for CO2 over N2 (155 and 414 for PPN-6-SO3H and PPN-6-SO3Li, respectively). Since these PPNs also possess ultrahigh physicochemical stability, practical applications in postcombustion capture of CO2 lie well within the realm of possibility.
Oliver Brüggemann - One of the best experts on this subject based on the ideXlab platform.
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Porous Polymer monoliths for small molecule separations: advancements and limitations
Analytical and Bioanalytical Chemistry, 2011Co-Authors: Ivo Nischang, Ian Teasdale, Oliver BrüggemannAbstract:Porous Polymer monoliths are considered to be one of the major breakthroughs in separation science. These materials are well known to be best suited for the separation of large molecules, specifically proteins, an observation most often explained by convective mass transfer and the absence of small pores in the Polymer scaffold. However, this conception is not sufficient to explain the performance of small molecules. This review focuses in particular on the preparation of (macro)Porous Polymer monoliths by simple free-radical processes and the key events in their formation. There is special focus on the fluid transport properties in the heterogeneous macropore space (flow dispersion) and on the transport of small molecules in the swollen, and sometimes permanently Porous, globule-scale Polymer matrix. For small molecule applications in liquid chromatography, it is consistently found in the literature that the major limit for the application of macroPorous Polymer monoliths lies not in the optimization of surface area and/or modification of the material and microscopic morphological properties only, but in the improvement of mass transfer properties. In this review we discuss the effect of resistance to mass transfer arising from the nanoscale gel porosity. Gel porosity induces stagnant mass transfer zones in chromatographic processes, which hamper mass transfer efficiency and have a detrimental effect on macroscopic chromatographic dispersion under equilibrium (isocratic) elution conditions. The inherent inhomogeneity of Polymer networks derived from free-radical cross-linking Polymerization, and hence the absence of a rigid (meso)Porous pore space, represents a major challenge for the preparation of efficient Polymeric materials for the separation of small molecules.
Jiayin Yuan - One of the best experts on this subject based on the ideXlab platform.
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An instant multi-responsive Porous Polymer actuator driven by solvent molecule sorption
Nature Communications, 2014Co-Authors: Qiang Zhao, Xunlin Qiu, Jan Heyda, Joachim Dzubiella, John W C Dunlop, Zibin Zhang, Feihe Huang, Markus Antonietti, Jiayin YuanAbstract:Fast actuation speed, large-shape deformation and robust responsiveness are critical to synthetic soft actuators. A simultaneous optimization of all these aspects without trade-offs remains unresolved. Here we describe Porous Polymer actuators that bend in response to acetone vapour (24 kPa, 20 °C) at a speed of an order of magnitude faster than the state-of-the-art, coupled with a large-scale locomotion. They are meanwhile multi-responsive towards a variety of organic vapours in both the dry and wet states, thus distinctive from the traditional gel actuation systems that become inactive when dried. The actuator is easy-to-make and survives even after hydrothermal processing (200 °C, 24 h) and pressing-pressure (100 MPa) treatments. In addition, the beneficial responsiveness is transferable, being able to turn ‘inert’ objects into actuators through surface coating. This advanced actuator arises from the unique combination of Porous morphology, gradient structure and the interaction between solvent molecules and actuator materials.Soft actuators bearing rapid responsiveness and large-scale actuation are desirable for many biomimetic applications. Here, Zhao et al.build a Polymer actuator with a Porous architecture, which allows a fast bending response at a timescale of seconds through absorbing a variety of solvent vapours.
