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Insung S Choi - One of the best experts on this subject based on the ideXlab platform.
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the control of cell adhesion and detachment on thin films of thermoresponsive poly n isopropylacrylamide r 3 methacryloylamino propyl dimethyl 3 sulfopropyl Ammonium Hydroxide
Biomaterials, 2009Co-Authors: Bokyung Kong, Joon Sung Choi, Saewha Jeon, Insung S ChoiAbstract:This paper describes the formation of poly(N-isopropylacrylamide) (PNIPAAm) and poly[(N-isopropylacrylamide)-r-((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)Ammonium Hydroxide)] (P(NIPAAm-r-MPDSAH)) films on a glass surface via surface-initiated, atom transfer radical polymerization as a cell-culture platform. The films of PNIPAAm with various thicknesses and of P(NIPAAm-r-MPDSAH) with various ratios of NIPAAm and MPDSAH are formed to investigate the behaviors of cell adhesion and detachment. In the case of the PNIPAAm-grafted glass surfaces, the optimal film thickness, achieving the effective control of both cell adhesion and detachment, is estimated to be 11-13 nm for NIH 3T3 fibroblast cells. The adhesion and detachment behaviors of NIH 3T3 fibroblast cells are further tuned by incorporating the hydrophilic and non-biofouling MPDSAH moiety into the PNIPAAm system. The cell adhesion and detachment are controlled best, when the ratio of NIPAAm and MPDSAH is 75:1 (NIPAAm:MPDSAH).
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highly efficient non biofouling coating of zwitterionic polymers poly 3 methacryloylamino propyl dimethyl 3 sulfopropyl Ammonium Hydroxide
Langmuir, 2007Co-Authors: Woo Kyung Cho, Bokyung Kong, Insung S ChoiAbstract:This work describes the formation of highly efficient non-biofouling polymeric thin films of poly((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)Ammonium Hydroxide), (poly(MPDSAH)). The poly(MPDSAH) films were generated from the self-assembled monolayers terminating in an initiator of atom transfer radical polymerization (ATRP) by the surface-initiated ATRP of MPDSAH. The poly(MPDSAH) films on a gold surface were characterized by ellipsometry, FT-IR spectroscopy, contact angle goniometery, and X-ray photoelectron spectroscopy. The copper complexes and unpolymerized monomers trapped inside the polymer brushes were completely washed out by soaking the poly(MPDSAH)-coated substrate in water at 40 °C for 4 days. The amount of proteins nonspecifically adsorbed onto the poly(MPDSAH) films was evaluated by surface plasmon resonance spectroscopy: the adsorption of proteins was <0.6 ng/cm2 on the surfaces for all the model proteins. The ability of the poly(MPDSAH) films to resist the nonspecific adsorption ...
Whangi Kim - One of the best experts on this subject based on the ideXlab platform.
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anion conductive poly tetraphenyl phthalazine ether sulfone containing tetra quaternary Ammonium Hydroxide for alkaline fuel cell application
International Journal of Hydrogen Energy, 2013Co-Authors: Dong Wan Seo, Youngdon Lim, Soonho Lee, Hyun Chul Lee, Mohammad Awlad Hossain, Ho Hyoun Jang, Seong Young Choi, Whangi KimAbstract:Abstract The poly(tetraphenyl ether ketone sulfone)s (PTPEKSs) were synthesized from 1,2-bis(4-fluorobenzoyl)-3,4,5,6-tetraphenyl benzene (BFBTPB) and bis(4-fluorophenyl) sulfone with bis(4-hydroxydiphenyl) sulfone in sulfolane. The synthesis of poly(tetraphenyl phthalazine ether sulfone)s (PTPPESs) was carried out via an intramolecular ring-closure reaction of dibenzoylbenzene moiety with hydrazine monohydrate. The PTPPES-QAHs [poly(tetraphenyl phthalazine ether sulfone-quaternary Ammonium Hydroxide)]s were synthesized via chloromethylation of PTPPES, quaternization with trimethylamine, and followed by an anion exchange of tetra-quaternary Ammonium chloride polymers with KOH. Different contents of quaternized unit in PTPPES-QAH (15, 20, 25 mol% of BFBTPB) were studied by FT-IR, 1 H NMR spectroscopy, and thermogravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction of quaternized polymers with water. The ion exchange capacity (IEC), ion conductivity and cell performance of PTPPES-QAH were evaluated with increasing the degree of quaternization.
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anion conductive poly arylene ether sulfone s containing tetra quaternary Ammonium Hydroxide on fluorenyl group for alkaline fuel cell application
Electrochimica Acta, 2012Co-Authors: Dong Wan Seo, Md Awlad Hossain, Donghoon Lee, Youngdon Lim, Soonho Lee, Hyun Chul Lee, Tae Whan Hong, Whangi KimAbstract:Abstract A series of poly(arylene ether sulfone)s containing tetra-quaternary Ammonium Hydroxide on fluorenyl group (QAPAES-OH) were synthesized via polycondensation, chloromethylation, quaternization, and the subsequent ion exchange reactions. The tetra-quaternary Ammonium Hydroxide polymers rendered an elevated molecular weight and exhibited an outstanding solubility in aprotic polar solvents. Consequently, flexible and tough alkaline membranes with varying ionic contents were obtained by an anion exchange of tetra-quaternary Ammonium chloride polymers with 1.0 M KOH at room temperature. Quaternization and the following ion exchange reactions were quantitative so that the obtained ionomer membranes could have high ion exchange capacity (IEC) upto 1.73 mmol g−1. High Hydroxide ion conductivity was achieved up to 30.7 mS cm−1 at 80 °C with the membrane of the highest IEC. The resulting polymers were characterized by 1H NMR, FT-IR, and TGA.
Bokyung Kong - One of the best experts on this subject based on the ideXlab platform.
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the control of cell adhesion and detachment on thin films of thermoresponsive poly n isopropylacrylamide r 3 methacryloylamino propyl dimethyl 3 sulfopropyl Ammonium Hydroxide
Biomaterials, 2009Co-Authors: Bokyung Kong, Joon Sung Choi, Saewha Jeon, Insung S ChoiAbstract:This paper describes the formation of poly(N-isopropylacrylamide) (PNIPAAm) and poly[(N-isopropylacrylamide)-r-((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)Ammonium Hydroxide)] (P(NIPAAm-r-MPDSAH)) films on a glass surface via surface-initiated, atom transfer radical polymerization as a cell-culture platform. The films of PNIPAAm with various thicknesses and of P(NIPAAm-r-MPDSAH) with various ratios of NIPAAm and MPDSAH are formed to investigate the behaviors of cell adhesion and detachment. In the case of the PNIPAAm-grafted glass surfaces, the optimal film thickness, achieving the effective control of both cell adhesion and detachment, is estimated to be 11-13 nm for NIH 3T3 fibroblast cells. The adhesion and detachment behaviors of NIH 3T3 fibroblast cells are further tuned by incorporating the hydrophilic and non-biofouling MPDSAH moiety into the PNIPAAm system. The cell adhesion and detachment are controlled best, when the ratio of NIPAAm and MPDSAH is 75:1 (NIPAAm:MPDSAH).
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highly efficient non biofouling coating of zwitterionic polymers poly 3 methacryloylamino propyl dimethyl 3 sulfopropyl Ammonium Hydroxide
Langmuir, 2007Co-Authors: Woo Kyung Cho, Bokyung Kong, Insung S ChoiAbstract:This work describes the formation of highly efficient non-biofouling polymeric thin films of poly((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)Ammonium Hydroxide), (poly(MPDSAH)). The poly(MPDSAH) films were generated from the self-assembled monolayers terminating in an initiator of atom transfer radical polymerization (ATRP) by the surface-initiated ATRP of MPDSAH. The poly(MPDSAH) films on a gold surface were characterized by ellipsometry, FT-IR spectroscopy, contact angle goniometery, and X-ray photoelectron spectroscopy. The copper complexes and unpolymerized monomers trapped inside the polymer brushes were completely washed out by soaking the poly(MPDSAH)-coated substrate in water at 40 °C for 4 days. The amount of proteins nonspecifically adsorbed onto the poly(MPDSAH) films was evaluated by surface plasmon resonance spectroscopy: the adsorption of proteins was <0.6 ng/cm2 on the surfaces for all the model proteins. The ability of the poly(MPDSAH) films to resist the nonspecific adsorption ...
Dong Wan Seo - One of the best experts on this subject based on the ideXlab platform.
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anion conductive poly tetraphenyl phthalazine ether sulfone containing tetra quaternary Ammonium Hydroxide for alkaline fuel cell application
International Journal of Hydrogen Energy, 2013Co-Authors: Dong Wan Seo, Youngdon Lim, Soonho Lee, Hyun Chul Lee, Mohammad Awlad Hossain, Ho Hyoun Jang, Seong Young Choi, Whangi KimAbstract:Abstract The poly(tetraphenyl ether ketone sulfone)s (PTPEKSs) were synthesized from 1,2-bis(4-fluorobenzoyl)-3,4,5,6-tetraphenyl benzene (BFBTPB) and bis(4-fluorophenyl) sulfone with bis(4-hydroxydiphenyl) sulfone in sulfolane. The synthesis of poly(tetraphenyl phthalazine ether sulfone)s (PTPPESs) was carried out via an intramolecular ring-closure reaction of dibenzoylbenzene moiety with hydrazine monohydrate. The PTPPES-QAHs [poly(tetraphenyl phthalazine ether sulfone-quaternary Ammonium Hydroxide)]s were synthesized via chloromethylation of PTPPES, quaternization with trimethylamine, and followed by an anion exchange of tetra-quaternary Ammonium chloride polymers with KOH. Different contents of quaternized unit in PTPPES-QAH (15, 20, 25 mol% of BFBTPB) were studied by FT-IR, 1 H NMR spectroscopy, and thermogravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction of quaternized polymers with water. The ion exchange capacity (IEC), ion conductivity and cell performance of PTPPES-QAH were evaluated with increasing the degree of quaternization.
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anion conductive poly arylene ether sulfone s containing tetra quaternary Ammonium Hydroxide on fluorenyl group for alkaline fuel cell application
Electrochimica Acta, 2012Co-Authors: Dong Wan Seo, Md Awlad Hossain, Donghoon Lee, Youngdon Lim, Soonho Lee, Hyun Chul Lee, Tae Whan Hong, Whangi KimAbstract:Abstract A series of poly(arylene ether sulfone)s containing tetra-quaternary Ammonium Hydroxide on fluorenyl group (QAPAES-OH) were synthesized via polycondensation, chloromethylation, quaternization, and the subsequent ion exchange reactions. The tetra-quaternary Ammonium Hydroxide polymers rendered an elevated molecular weight and exhibited an outstanding solubility in aprotic polar solvents. Consequently, flexible and tough alkaline membranes with varying ionic contents were obtained by an anion exchange of tetra-quaternary Ammonium chloride polymers with 1.0 M KOH at room temperature. Quaternization and the following ion exchange reactions were quantitative so that the obtained ionomer membranes could have high ion exchange capacity (IEC) upto 1.73 mmol g−1. High Hydroxide ion conductivity was achieved up to 30.7 mS cm−1 at 80 °C with the membrane of the highest IEC. The resulting polymers were characterized by 1H NMR, FT-IR, and TGA.
Bart Van Der Bruggen - One of the best experts on this subject based on the ideXlab platform.
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synthesis of quaternary Ammonium Hydroxide from its halide salt by bipolar membrane electrodialysis bmed effect of molecular structure of Ammonium compounds on the process performance
Journal of Chemical Technology & Biotechnology, 2014Co-Authors: Jiangnan Shen, Lifen Liu, Jiuyang Lin, Bart Van Der BruggenAbstract:BACKGROUND Conventional methods for synthesis of quaternary Ammonium Hydroxides, such as the reaction of quaternary Ammonium chloride, ion-exchange and electro-electrodialysis cannot achieve benign production of QAOH without secondary pollution. The objective of the present study was to develop bipolar membrane electrodialysis with a novel stack configuration as an improved method to prepare high purity quaternary Ammonium Hydroxide from its halide salt. RESULTS To investigate the synthesis of quaternary Ammonium Hydroxide (QAOH) with high purity by using electrodialysis with bipolar membranes (BMED), four different types of quaternary Ammonium Hydroxides (tetramethylAmmonium Hydroxide, TMAOH; tetrapropylAmmonium Hydroxide, TPAOH; methyltriethylAmmonium Hydroxide, MTAOH; and benzyltrimethylAmmonium Hydroxide, BTAOH) were chosen as the target products. The effect of the molecular structure of four different types of halide salts (NR4X) on the BMED performance was studied by investigating operating parameters such as current density, feed concentration and feed flow velocity and energy consumption on the basis of ion dimensions and molecular weight, ion electrophoretic mobility and the interaction between Ammoniums and membranes. The results indicate that it is feasible to obtain quaternary Ammonium Hydroxides with high purity (Cl−/Br− content < 500 ppm) by BMED with a novel four-compartment configuration in view of environmental aspects. CONCLUSION For converting higher molecule size halide salts, the process performance was lower, while the energy consumption increased, at similar experimental conditions, which is in line with the theory. © 2014 Society of Chemical Industry.
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preparation of highly pure tetrapropyl Ammonium Hydroxide using continuous bipolar membrane electrodialysis
Chemical Engineering Journal, 2013Co-Authors: Jiangnan Shen, Jie Huang, Bart Van Der BruggenAbstract:Abstract Conventional methods of tetrapropyl Ammonium Hydroxide (TPAOH) production via electrolysis, reaction of tetrapropyl Ammonium halide with silver oxide, and ion-exchange suffer from high production costs, low quality, and environmental pollution. In this work, continuous bipolar membrane electrodialysis (BMED) is employed for the preparation of TPAOH from its halide as a sustainable alternative process. Novel ion-exchange membranes were developed for lab and pilot scale experiments, which indicate an acceptable current efficiency and energy consumption. The results indicate that a cell configuration with four compartments yielded the best results when the salt concentration was 0.3 mol L −1 and the current density was 200 A m −2 . The highest conversion in electrodialysis was 91.6%, with a high purity of trace alkali metal ions and low Br − content (176 ppm) at a TPAOH concentration of 25%. The energy consumption is 1.897 kW h kg −1 . Continuous pilot experiments demonstrate the feasibility of manufacturing TPAOH by direct splitting its halide for industrial application.