Methyl methacrylate （MMA） was polymerized by using of benzoyl peroxide （BPO） and N, N-dimethylaniline （DMA） as an redox initiator in fluorous triphasic system at room temperature. The polymerization was occurred...Methyl methacrylate （MMA） was polymerized by using of benzoyl peroxide （BPO） and N, N-dimethylaniline （DMA） as an redox initiator in fluorous triphasic system at room temperature. The polymerization was occurred in both initiator layer and monomer layer in a U-tube. It was found that PMMA obtained from the initiator layer with relatively narrow polydispersity.（PDI = 1.38）展开更多
Fiber-shaped energy storage devices(FSESDs)with exceptional flexibility for wearable power sources should be applied with solid electrolytes over liquid electrolytes due to short circuits and leakage issue during defo...Fiber-shaped energy storage devices(FSESDs)with exceptional flexibility for wearable power sources should be applied with solid electrolytes over liquid electrolytes due to short circuits and leakage issue during deformation.Among the solid options,polymer electrolytes are particularly preferred due to their robustness and flexibility,although their low ionic conductivity remains a significant challenge.Here,we present a redox polymer electrolyte(HT_RPE)with 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl(HT)as a multi-functional additive.HT acts as a plasticizer that transforms the glassy state into the rubbery state for improved chain mobility and provides distinctive ion conduction pathway by the self-exchange reaction between radical and oxidized species.These synergetic effects lead to high ionic conductivity(73.5 mS cm−1)based on a lower activation energy of 0.13 eV than other redox additives.Moreover,HT_RPE with a pseudocapacitive characteristic by HT enables an outstanding electrochemical performance of the symmetric FSESDs using carbon-based fiber electrodes(energy density of 25.4 W h kg^(−1) at a power density of 25,000 W kg^(−1))without typical active materials,along with excellent stability(capacitance retention of 91.2%after 8,000 bending cycles).This work highlights a versatile HT_RPE that utilizes the unique functionality of HT for both the high ionic conductivity and improved energy storage capability,providing a promising pathway for next-generation flexible energy storage devices.展开更多
Flexible fibrous supercapacitors(FFS)are taking account of as the energy storage devices for wearable electronics owing to their high power density,high safety,long cycle life,and simple manufacturing process.Neverthe...Flexible fibrous supercapacitors(FFS)are taking account of as the energy storage devices for wearable electronics owing to their high power density,high safety,long cycle life,and simple manufacturing process.Nevertheless,FFSs have the disadvantage of low specific capacitance that results from the electrochemical characteristics of the electrical double layer on the carbon fiber electrode.In this study,for the first time,an FFS comprising surface-activated carbon fibers as an electrode/current collector and a redox additive gel polymer electrolyte(FFS-SARE)was fabricated for use as a wearable energy storage device.The FFS-SARE showed outstanding electrochemical performance,namely,high specific capacitances of 891 and 399 mF cm^(-2) at current densities of 70.0 and 400 μA cm^(-2),respectively,and remarkable ultrafast cycling stability over 5000 cycles with 92%capacitance retention at a current density of 400.0 μA cm^(-2).Moreover,they exhibited mechanical flexibility and had high feasibility,and they showed good energy storage performance that renders them suitable for use in wearable electronic textiles.展开更多
Conventional chloromethylation, paraformaldehyde/hydrogen chloride in acetic acid medium, was applied to 1,2- dimethoxybenzene. Chloroform-soluble poly（3,4-dimethoxy-o-tolylene） was obtained with an intrinsic viscos...Conventional chloromethylation, paraformaldehyde/hydrogen chloride in acetic acid medium, was applied to 1,2- dimethoxybenzene. Chloroform-soluble poly（3,4-dimethoxy-o-tolylene） was obtained with an intrinsic viscosity of 0.034 dL g^-1. The polymer was evaluated as a condensation redox polymer precursor formed by a Friedel-Crafts reaction. Cleavage of the methoxy groups present in this polymer resulted in poly（3,4-dihydroxy-o-tolylene） which manifested a great air-oxidation resistance. The redox property of the latter polymer was found to be 1017 mV by potentiometric titration with 0.05 N ceric ammonium nitrate at 25℃. This midpotential was compared to that of catechol, a monomeric analogue, under the same titration conditions.展开更多
An enzyme biosensor for amperometric measurement of aspartate aminotransferase has been developed.The working electrode was modified with a thin-film of redox polymer,then glutamate oxidase,with the immobilized reagen...An enzyme biosensor for amperometric measurement of aspartate aminotransferase has been developed.The working electrode was modified with a thin-film of redox polymer,then glutamate oxidase,with the immobilized reagent cast and dried on the electrode.The biosensor responses to AST by detecting hydrogen peroxide were produced by enzymical reaction at-0.1 V with a response time of 120 seconds.The electrode gave a detection limit of 32.5 U/L with a linear concentration range of 32.5 U/L～2000 U/L in serum.Due to more sensitive and lower detection limit,the biosensor is expected mainly to be used for physiological identification and physical performance of athletes in the future.Extended application will also affect the practice of clinical medicine for the diagnosis of heart and liver disease.展开更多
A hydrophilic radical polymer, poly（2,2,6,6-teteramethylpiperidinyloxyl-4-yl acrylamide） （PTAm）, was synthesized via oxidation of the corresponding precursor polymer, poly（2,2,6,6-teteramethylpiperidine-4-yl acry...A hydrophilic radical polymer, poly（2,2,6,6-teteramethylpiperidinyloxyl-4-yl acrylamide） （PTAm）, was synthesized via oxidation of the corresponding precursor polymer, poly（2,2,6,6-teteramethylpiperidine-4-yl acrylamide）. Electrochemical properties of the PTAm layer were characterized in three aqueous electrolytes of sodium chloride （NaCl）, sodium tetrafluoroborate （NaBF4）, and sodium hexafluorophosphate （NaPF6） to optimize its activity as an organic cathode. The counter anion species significantly affected the capacity and the cycle performance of the PTAm layer. The PTAm layer in the presence of BF4？ displayed quantitative redox capacity beyond 1 μm layer thickness and maintained the discharging capacity of 110 mAh g-1 （97% vs. the calculated capacity） even after 1000 cycle charging/discharging, which could be ascribed to its appropriate affinity to the aqueous electrolyte without any dissolution into the electrolyte. A totally organic-based rechargeable cell was fabricated using PTAm and poly（N-4,4＇-bipyridinium-N-decamethylene dibromide） as the cathode and the anode, respectively, and the aqueous electrolyte of NaBF4. The cell gave a plateau voltage at 1.2 V both on charging and discharging and an excellent charging/discharging cyclability of ＆gt;2000 with high coulombic efficiency of ＆gt;95%.展开更多
文摘Methyl methacrylate （MMA） was polymerized by using of benzoyl peroxide （BPO） and N, N-dimethylaniline （DMA） as an redox initiator in fluorous triphasic system at room temperature. The polymerization was occurred in both initiator layer and monomer layer in a U-tube. It was found that PMMA obtained from the initiator layer with relatively narrow polydispersity.（PDI = 1.38）
基金supported by Korea Institute of Science and Technology(KIST)Institutional Program and Open Research Program(ORP)This work was also supported by grant from the National Research Foundation(NRF)of Korea government(RS-2024-00433159 and RS-2023-00208313)from ITECH R&D program of MOTIE/KEIT(RS-2023-00257573).
文摘Fiber-shaped energy storage devices(FSESDs)with exceptional flexibility for wearable power sources should be applied with solid electrolytes over liquid electrolytes due to short circuits and leakage issue during deformation.Among the solid options,polymer electrolytes are particularly preferred due to their robustness and flexibility,although their low ionic conductivity remains a significant challenge.Here,we present a redox polymer electrolyte(HT_RPE)with 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl(HT)as a multi-functional additive.HT acts as a plasticizer that transforms the glassy state into the rubbery state for improved chain mobility and provides distinctive ion conduction pathway by the self-exchange reaction between radical and oxidized species.These synergetic effects lead to high ionic conductivity(73.5 mS cm−1)based on a lower activation energy of 0.13 eV than other redox additives.Moreover,HT_RPE with a pseudocapacitive characteristic by HT enables an outstanding electrochemical performance of the symmetric FSESDs using carbon-based fiber electrodes(energy density of 25.4 W h kg^(−1) at a power density of 25,000 W kg^(−1))without typical active materials,along with excellent stability(capacitance retention of 91.2%after 8,000 bending cycles).This work highlights a versatile HT_RPE that utilizes the unique functionality of HT for both the high ionic conductivity and improved energy storage capability,providing a promising pathway for next-generation flexible energy storage devices.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(NRF-2020R1C1C1010611).
文摘Flexible fibrous supercapacitors(FFS)are taking account of as the energy storage devices for wearable electronics owing to their high power density,high safety,long cycle life,and simple manufacturing process.Nevertheless,FFSs have the disadvantage of low specific capacitance that results from the electrochemical characteristics of the electrical double layer on the carbon fiber electrode.In this study,for the first time,an FFS comprising surface-activated carbon fibers as an electrode/current collector and a redox additive gel polymer electrolyte(FFS-SARE)was fabricated for use as a wearable energy storage device.The FFS-SARE showed outstanding electrochemical performance,namely,high specific capacitances of 891 and 399 mF cm^(-2) at current densities of 70.0 and 400 μA cm^(-2),respectively,and remarkable ultrafast cycling stability over 5000 cycles with 92%capacitance retention at a current density of 400.0 μA cm^(-2).Moreover,they exhibited mechanical flexibility and had high feasibility,and they showed good energy storage performance that renders them suitable for use in wearable electronic textiles.
文摘Conventional chloromethylation, paraformaldehyde/hydrogen chloride in acetic acid medium, was applied to 1,2- dimethoxybenzene. Chloroform-soluble poly（3,4-dimethoxy-o-tolylene） was obtained with an intrinsic viscosity of 0.034 dL g^-1. The polymer was evaluated as a condensation redox polymer precursor formed by a Friedel-Crafts reaction. Cleavage of the methoxy groups present in this polymer resulted in poly（3,4-dihydroxy-o-tolylene） which manifested a great air-oxidation resistance. The redox property of the latter polymer was found to be 1017 mV by potentiometric titration with 0.05 N ceric ammonium nitrate at 25℃. This midpotential was compared to that of catechol, a monomeric analogue, under the same titration conditions.
文摘An enzyme biosensor for amperometric measurement of aspartate aminotransferase has been developed.The working electrode was modified with a thin-film of redox polymer,then glutamate oxidase,with the immobilized reagent cast and dried on the electrode.The biosensor responses to AST by detecting hydrogen peroxide were produced by enzymical reaction at-0.1 V with a response time of 120 seconds.The electrode gave a detection limit of 32.5 U/L with a linear concentration range of 32.5 U/L～2000 U/L in serum.Due to more sensitive and lower detection limit,the biosensor is expected mainly to be used for physiological identification and physical performance of athletes in the future.Extended application will also affect the practice of clinical medicine for the diagnosis of heart and liver disease.
基金supported by Grants-in-Aid for Scientific Research (19105003)Global COE Program at Waseda University from MEXT, JapanResearch Project "Radical Polymers" at Advanced Research Institute for Science & Engineering, Waseda University
文摘A hydrophilic radical polymer, poly（2,2,6,6-teteramethylpiperidinyloxyl-4-yl acrylamide） （PTAm）, was synthesized via oxidation of the corresponding precursor polymer, poly（2,2,6,6-teteramethylpiperidine-4-yl acrylamide）. Electrochemical properties of the PTAm layer were characterized in three aqueous electrolytes of sodium chloride （NaCl）, sodium tetrafluoroborate （NaBF4）, and sodium hexafluorophosphate （NaPF6） to optimize its activity as an organic cathode. The counter anion species significantly affected the capacity and the cycle performance of the PTAm layer. The PTAm layer in the presence of BF4？ displayed quantitative redox capacity beyond 1 μm layer thickness and maintained the discharging capacity of 110 mAh g-1 （97% vs. the calculated capacity） even after 1000 cycle charging/discharging, which could be ascribed to its appropriate affinity to the aqueous electrolyte without any dissolution into the electrolyte. A totally organic-based rechargeable cell was fabricated using PTAm and poly（N-4,4＇-bipyridinium-N-decamethylene dibromide） as the cathode and the anode, respectively, and the aqueous electrolyte of NaBF4. The cell gave a plateau voltage at 1.2 V both on charging and discharging and an excellent charging/discharging cyclability of ＆gt;2000 with high coulombic efficiency of ＆gt;95%.
