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Jeanfrancois Gohy - One of the best experts on this subject based on the ideXlab platform.
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supramolecular assemblies from poly styrene block poly 4 Vinylpyridine diblock copolymers mixed with 6 hydroxy 2 naphthoic acid
Polymers, 2013Co-Authors: Bhavesh Bharatiya, Jean Marc Schumers, Elio Poggi, Jeanfrancois GohyAbstract:Supramolecular assemblies involving interaction of a small organic molecule, 2-hydroxy-6-Naphthoic acid (HNA), with poly(styrene)-block-poly(4-Vinylpyridine) (PS-b-P4VP) diblock copolymers are utilized to obtain micellar structures in solution, nanostructured thin films on flat substrates and, finally, nanoporous thin films. The formation of hydrogen bonds between HNA and the poly(4-Vinylpyridine) (P4VP) blocks is confirmed by spectroscopic measurements. The accordingly P4VP/HNA hydrogen-bonded complexes are poorly soluble in 1,4-dioxane, resulting in the formation of micellar structures with a P4VP/HNA core and a polystyrene (PS) corona. Those micelles have been spin-coated onto silicon wafers, resulting in nanostructured thin films consisting of P4VP/HNA dot-like features embedded in a PS matrix. The morphology of those films has been tuned by solvent annealing. Selective dissolution of HNA by methanol results in the formation of a nanoporous thin film. The P4VP/HNA nanodomains have been also cross-linked by borax, and the thin films have been further dissolved in a good solvent for PS, leading to micelles with a structure reminiscent of the thin films.
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supramolecular assemblies from poly styrene block poly 4 Vinylpyridine diblock copolymers mixed with 6 hydroxy 2 naphthoic acid
Polymers, 2013Co-Authors: Bhavesh Bharatiya, Jean Marc Schumers, Elio Poggi, Jeanfrancois GohyAbstract:Supramolecular assemblies involving interaction of a small organic molecule, 2-hydroxy-6-Naphthoic acid (HNA), with poly(styrene)-block-poly(4-Vinylpyridine) (PS-b-P4VP) diblock copolymers are utilized to obtain micellar structures in solution, nanostructured thin films on flat substrates and, finally, nanoporous thin films. The formation of hydrogen bonds between HNA and the poly(4-Vinylpyridine) (P4VP) blocks is confirmed by spectroscopic measurements. The accordingly P4VP/HNA hydrogen-bonded complexes are poorly soluble in 1,4-dioxane, resulting in the formation of micellar structures with a P4VP/HNA core and a polystyrene (PS) corona. Those micelles have been spin-coated onto silicon wafers, resulting in nanostructured thin films consisting of P4VP/HNA dot-like features embedded in a PS matrix. The morphology of those films has been tuned by solvent annealing. Selective dissolution of HNA by methanol results in the formation of a nanoporous thin film. The P4VP/HNA nanodomains have been also cross-linked by borax, and the thin films have been further dissolved in a good solvent for PS, leading to micelles with a structure reminiscent of the thin films. © 2013 by the authors.
E T Kang - One of the best experts on this subject based on the ideXlab platform.
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electroless plating of copper on polyimide films modified by surface initiated atom transfer radical polymerization of 4 Vinylpyridine
Applied Surface Science, 2008Co-Authors: Liang Li, Jiangyu Wu, Xianghua Yu, E T KangAbstract:Abstract Surface modification of polyimide (PI) films were first carried out by chloromethylation under mild conditions, followed by surface-initiated atom-transfer radical polymerization (ATRP) of 4-Vinylpyridine (4VP) from the chloromethylated PI surfaces. The composition and topography of the PI surfaces modified by poly(4-Vinylpyridine) (P4VP) were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), respectively. The P4VP brushes with well-preserved pyridine groups on the PI surface was used not only as the chemisorption sites for the palladium complexes without prior sensitization by SnCl 2 solution during the electroless plating of copper, but also as an adhesion promotion layer to enhance the adhesion of the electrolessly deposited copper to the PI surfaces. The T-peel adhesion strength of the electrolessly deposited copper on the modified PI surface could reach about 6.6 N/cm. Effects of the polymerization time and the activation time in the PdCl 2 solution on the T-peel adhesion strength of the electrolessly deposited copper in the Sn-free process to the modified PI surface were also studied.
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polymer microspheres with permanent antibacterial surface from surface initiated atom transfer radical polymerization of 4 Vinylpyridine and quaternization
Surface Review and Letters, 2006Co-Authors: Zhenping Cheng, K G Neoh, Xiulin Zhu, Z L Shi, E T KangAbstract:Crosslinked poly(4-vinylbenzyl chloride) (PVBC) microspheres of about 550 μm in diameter were first synthesized by suspension copolymerization of 4-vinylbenzyl chloride (VBC) in the presence of a crosslinking agent, ethylene glycol dimethacrylate (EGDMA). Subsequent surface-initiated atom transfer radical polymerization (ATRP) of 4-Vinylpyridine (4VP), using the VBC units of PVBC on the microsphere surface as the macroinitiators, produced well-defined (nearly monodisperse) and covalently tethered poly(4-Vinylpyridine) (P4VP) brushes. Quaternization of the tertiary amine groups of the P4VP brushes with hexyl bromide gave rise to a high concentration of quaternary ammonium salt (QAS) on the microsphere surfaces. The chemical composition of the microsphere surfaces at various stages of surface modification was characterized by X-ray photoelectron spectroscopy (XPS). The bactericidal effect of the QAS-functionalized microspheres on Escherichia coli (E. coli) was demonstrated. No significant loss in the surface bactericidal activity of the microsphere was observed during repeated applications.
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ph effect of coagulation bath on the characteristics of poly acrylic acid grafted and poly 4 Vinylpyridine grafted poly vinylidene fluoride microfiltration membranes
Joint International Conference on Information Sciences, 2003Co-Authors: Lei Ying, Guangqun Zhai, A Y Winata, E T Kang, K G NeohAbstract:The poly(acrylic acid)-graft-poly(vinylidene fluoride) (PAAc-g-PVDF) and poly(4-Vinylpyridine)-graft-poly(vinylidene fluoride) (P4VP-g-PVDF) copolymers were obtained by thermally induced molecular graft copolymerization of acrylic acid (AAc) and 4-Vinylpyridine (4VP), respectively, with the ozone-pretreated poly(vinylidene fluoride) (PVDF) in N-methyl-2-pyrrolidone (NMP) solution. Microfiltration (MF) membranes were prepared from the respective copolymers by phase inversion in aqueous media. The effects of pH of the coagulation bath on the physicochemical and morphological characteristics of the membranes were investigated. The surface compositions of the membranes were determined by X-ray photoelectron spectroscopy (XPS). The surface graft concentration of the AAc polymer for the PAAc-g-PVDF MF membrane increased with decreasing pH value of the coagulation bath. Completely opposite pH-dependent behavior was observed for the surface graft concentration of the 4VP polymer in the P4VP-g-PVDF MF membranes. A substantial increase in mean pore size was observed for the PAAc-g-PVDF MF membranes cast in basic coagulation baths of increasing pH. In the case of the P4VP-g-PVDF MF membranes, a substantial increase in mean pore size was observed for membranes cast in low pH (acidic) baths. The permeation rate of aqueous solutions through the PAAc-g-PVDF and P4VP-g-PVDF MF membranes exhibited a reversible dependence on the pH of the solution, with the membranes cast near the neutral pH exhibiting the highest sensitivity to changes in permeate pH.
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electroless plating of copper on polyimide films modified by plasma graft copolymerization with 4 Vinylpyridine
Applied Surface Science, 2002Co-Authors: Wen Wang, E T Kang, K G NeohAbstract:Abstract Surface modification of argon plasma-pretreated polyimide (PI, Kapton® HN) films by plasma graft copolymerization with 4-Vinylpyridine (4VP) was carried out. The effects of glow discharge conditions on the chemical composition and structure of the plasma-polymerized 4VP (pp-4VP) films were analyzed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy, respectively. The XPS and FTIR results revealed that the pyridine groups in the pp-4VP layer could be preserved to a large extent under proper glow discharge condition. The topography of the modified PI surface was investigated by atomic force microscopy (AFM). The pp-4VP film with well-preserved pyridine groups was used not only as the chemisorption sites for the palladium complexes (without the need for prior sensitization by SnCl2) during the electroless plating of copper, but also as an adhesion promotion layer to enhance the adhesion of the electrolessly deposited copper with the PI film. The T-peel adhesion strength of the electrolessly deposited copper to the pp-4VP grafted PI (pp-4VP-PI) film could reach about 7 N/cm. This adhesion strength was much higher than that of the electrolessly deposited copper to the pristine or the Ar plasma-treated PI film.
Jun Ichi Anzai - One of the best experts on this subject based on the ideXlab platform.
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a poly 4 Vinylpyridine derivative bearing os 5 6 dmphen 2cl 5 6 dmphen 5 6 dimethyl 1 10 phenanthroline a novel electrochemical indicator for detecting dna hybridization
Materials Science and Engineering: C, 2004Co-Authors: Aihua Liu, Jun Ichi AnzaiAbstract:Abstract A poly(4-Vinylpyridine) (PVP) derivative bearing a redox active osmium (Os) complex, Os(5,6-dmphen)2Cl-PVP, shows a selective binding to double-helical DNA chains, enabling the electrochemical determination of DNA in a picomolar level.
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use of polymeric indicator for electrochemical dna sensors poly 4 Vinylpyridine derivative bearing os 5 6 dimethyl 1 10 phenanthroline 2cl 2
Analytical Chemistry, 2004Co-Authors: Aihua Liu, Jun Ichi AnzaiAbstract:A poly(4-Vinylpyridine) (PVP) derivative bearing redox-active osmium complexes, PVP-[Os(5,6-dmphen)2Cl]2+ (5,6-dmphen = 5,6-dimethyl-1,10-phenanthroline), was employed as a hybridization indicator for electrochemical DNA sensors. PVP-[Os(5,6-dmphen)2Cl]2+ exhibited ∼1000 times higher sensitivity than the corresponding monomeric analogue, [Os(5,6-dmphen)3]2+, in DNA determination due to polymeric effects. The detection limit of the present sensor was ∼0.5 amol. Another merit of the polymeric indicator is that the redox potential was found to be +360 mV (vs Ag/AgCl), which is significantly lower than that reported for the monomeric analogue (+672 mV). The polymeric indicator was applicable to the discrimination of single- and double-base-mismatched DNAs from fully matched target DNA. The polymeric indicator can be removed from the electrode surface by rinsing the electrode in a high-temperature buffer for 6 min, and thus, the polymeric indicator-based DNA sensor can be used repeatedly.
Bhavesh Bharatiya - One of the best experts on this subject based on the ideXlab platform.
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supramolecular assemblies from poly styrene block poly 4 Vinylpyridine diblock copolymers mixed with 6 hydroxy 2 naphthoic acid
Polymers, 2013Co-Authors: Bhavesh Bharatiya, Jean Marc Schumers, Elio Poggi, Jeanfrancois GohyAbstract:Supramolecular assemblies involving interaction of a small organic molecule, 2-hydroxy-6-Naphthoic acid (HNA), with poly(styrene)-block-poly(4-Vinylpyridine) (PS-b-P4VP) diblock copolymers are utilized to obtain micellar structures in solution, nanostructured thin films on flat substrates and, finally, nanoporous thin films. The formation of hydrogen bonds between HNA and the poly(4-Vinylpyridine) (P4VP) blocks is confirmed by spectroscopic measurements. The accordingly P4VP/HNA hydrogen-bonded complexes are poorly soluble in 1,4-dioxane, resulting in the formation of micellar structures with a P4VP/HNA core and a polystyrene (PS) corona. Those micelles have been spin-coated onto silicon wafers, resulting in nanostructured thin films consisting of P4VP/HNA dot-like features embedded in a PS matrix. The morphology of those films has been tuned by solvent annealing. Selective dissolution of HNA by methanol results in the formation of a nanoporous thin film. The P4VP/HNA nanodomains have been also cross-linked by borax, and the thin films have been further dissolved in a good solvent for PS, leading to micelles with a structure reminiscent of the thin films.
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supramolecular assemblies from poly styrene block poly 4 Vinylpyridine diblock copolymers mixed with 6 hydroxy 2 naphthoic acid
Polymers, 2013Co-Authors: Bhavesh Bharatiya, Jean Marc Schumers, Elio Poggi, Jeanfrancois GohyAbstract:Supramolecular assemblies involving interaction of a small organic molecule, 2-hydroxy-6-Naphthoic acid (HNA), with poly(styrene)-block-poly(4-Vinylpyridine) (PS-b-P4VP) diblock copolymers are utilized to obtain micellar structures in solution, nanostructured thin films on flat substrates and, finally, nanoporous thin films. The formation of hydrogen bonds between HNA and the poly(4-Vinylpyridine) (P4VP) blocks is confirmed by spectroscopic measurements. The accordingly P4VP/HNA hydrogen-bonded complexes are poorly soluble in 1,4-dioxane, resulting in the formation of micellar structures with a P4VP/HNA core and a polystyrene (PS) corona. Those micelles have been spin-coated onto silicon wafers, resulting in nanostructured thin films consisting of P4VP/HNA dot-like features embedded in a PS matrix. The morphology of those films has been tuned by solvent annealing. Selective dissolution of HNA by methanol results in the formation of a nanoporous thin film. The P4VP/HNA nanodomains have been also cross-linked by borax, and the thin films have been further dissolved in a good solvent for PS, leading to micelles with a structure reminiscent of the thin films. © 2013 by the authors.
Volker Abetz - One of the best experts on this subject based on the ideXlab platform.
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isoporous membranes from novel polystyrene b poly 4 Vinylpyridine b poly solketal methacrylate ps b p4vp b psma triblock terpolymers and their post modification
Polymers, 2019Co-Authors: Sarah Saleem, Volkan Filiz, Clarissa Abetz, Volker Abetz, Sofia RangouAbstract:In this paper, the formation of nanostructured triblock terpolymer polystyrene-b-poly(4-Vinylpyridine)-b-poly(solketal methacrylate) (PS-b-P4VP-b-PSMA), polystyrene-b-poly(4-Vinylpyridine)-b-poly(glyceryl methacrylate) (PS-b-P4VP-b-PGMA) membranes via block copolymer self-assembly followed by non-solvent-induced phase separation (SNIPS) is demonstrated. An increase in the hydrophilicity was observed after treatment of non-charged isoporous membranes from PS-b-P4VP-b-PSMA, through acidic hydrolysis of the hydrophobic poly(solketal methacrylate) PSMA block into a hydrophilic poly(glyceryl methacrylate) PGMA block, which contains two neighbored hydroxyl (–OH) groups per repeating unit. For the first time, PS-b-P4VP-b-PSMA triblock terpolymers with varying compositions were successfully synthesized by sequential living anionic polymerization. Composite membranes of PS-b-P4VP-b-PSMA and PS-b-P4VP-b-PGMA triblock terpolymers with ordered hexagonally packed cylindrical pores were developed. The morphology of the membranes was studied with scanning electron microscopy (SEM) and atomic force microscopy (AFM). PS-b-P4VP-b-PSMA triblock terpolymer membranes were further treated with acid (1 M HCl) to get polystyrene-b-poly(4-Vinylpyridine)-b-poly(glyceryl methacrylate) (PS-b-P4VP-b-PGMA). Notably, the pristine porous membrane structure could be maintained even after acidic hydrolysis. It was found that membranes containing hydroxyl groups (PS-b-P4VP-b-PGMA) show a stable and higher water permeance than membranes without hydroxyl groups (PS-b-P4VP-b-PSMA), what is due to the increase in hydrophilicity. The membrane properties were analyzed further by contact angle, protein retention, and adsorption measurements.
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quaternization of a polystyrene block poly 4 Vinylpyridine isoporous membrane an approach to tune the pore size and the charge density
Macromolecular Rapid Communications, 2019Co-Authors: Zhenzhen Zhang, Md Mushfequr Rahman, Clarissa Abetz, Barbara Bajer, Jiali Wang, Volker AbetzAbstract:Isoporous integral asymmetric membranes derived from the self-assembly of block copolymers combined with the non-solvent-induced phase separation (SNIPS) have gained great attention. To extend their utility, good control over pore size and surface functionality in a facile manner is highly desirable. Here, an approach is proposed to achieve this by quaternization of the poly(4-Vinylpyridine) moiety of a polystyrene-block-poly(4-Vinylpyridine) SNIPS membrane using alkyl iodides via a scalable gas-solid heterogeneous reaction. By changing the size of the alkyl groups of the quaternization agent and the degree of quaternization, the effective pore size of the membrane is tailored in a wide range from the ultrafiltration to the nanofiltration regime. A quaternization of approximately half of the 4VP repeating units of the membranes with methyl iodide, ethyl iodide, or 1-propyl iodide leads to a retention of methylene blue from a 10 mg L-1 aqueous solution of 96%, 87%, and 83%, respectively.
