The Experts below are selected from a list of 13419 Experts worldwide ranked by ideXlab platform
U V Patil - One of the best experts on this subject based on the ideXlab platform.
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room temperature ammonia sensor based on Copper Nanoparticle intercalated polyaniline nanocomposite thin films
Applied Surface Science, 2015Co-Authors: U V Patil, Niranjan S Ramgir, N Karmakar, A Bhogale, A K Debnath, D K Aswal, S K Gupta, D C KothariAbstract:Abstract Thin films of Copper Nanoparticles intercalated-polyaniline nanocomposites (NC) have been deposited at room temperatures by in situ oxidative polymerization of aniline in the presence of different concentrations of Cu Nanoparticles. The response characteristics of the NC thin films toward different gases namely NH3, CO, CO2, NO and CH4 were examined at room temperature. Both pure polyaniline (PANI) and NC films exhibited a selective response toward NH3. Incorporation of Cu Nanoparticles resulted in an improvement of the sensors response and response kinetics. The response and the recovery times of composite film toward 50 ppm of NH3 were 7 and 160 s, respectively. Additionally, the NC sensor film could reversibly detect as low as 1 ppm of NH3 concentrations. The enhanced response of NC films toward NH3 is attributed to the deprotonation and reprotonation processes as also supported by Raman investigations.
Wanho Chung - One of the best experts on this subject based on the ideXlab platform.
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temperature changes of Copper Nanoparticle ink during flash light sintering
Journal of Materials Processing Technology, 2014Co-Authors: Sunghyeon Park, Wanho Chung, Haksung KimAbstract:Abstract The Copper Nanoparticle ink was coated on polyimide substrates using a doctor blade method. The films thus formed were then sintered by flash light irradiation at room temperature under ambient conditions. The flash light energy was varied from 2 J/cm 2 to 12 J/cm 2 . To measure the temperature change, a non-inverting amplifier circuit with an op-amp and a type-K thermocouple was devised. The sheet resistance change was simultaneously monitored using a Wheatstone bridge circuit. An analytical temperature calculation was conducted, considering the heat transfer phenomena during the flash light irradiation. As the results, the temperature of the Copper Nanoparticle films was reached to (318 °C) in 10 ms at the flash light irradiation energy higher than 12 J/cm 2 and they were melted and fully sintered. The analytical solutions of the temperature profile of Copper Nanoparticles film and polyimide substrate (maximum temperature of Copper Nanoparticles film and polyimide substrates are 279 °C and 140 °C, respectively) in which the latent heats for phase changes of the Copper Nanoparticles and the binder (PVP) were concerned, agrees well with the experimentally measured temperature profiles of them (maximum temperature of Copper Nanoparticles film and polyimide substrates are 318 °C and 135 °C, respectively). The analytical calculation method proposed, could be used to design the flash light sintering variables applicable to various low-temperature flexible substrates.
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in situ monitoring of flash light sintering of Copper Nanoparticle ink for printed electronics
Nanotechnology, 2012Co-Authors: Hyunjun Hwang, Wanho ChungAbstract:In this work, a flash-light sintering process for Cu nanoinks was studied. In order to precisely monitor the milliseconds flash-light sintering process, a real-time Wheatstone bridge electrical circuit and a high-rate data acquisition system were used. The effects of several flash-light irradiation conditions (irradiation energy, pulse number, on-time, and off-time) and the effects of the amount of poly(N-vinylpyrrolidone) in the Cu nanoink on the flash-light sintering process were investigated. The microstructures of the sintered Cu films were analyzed by scanning electron microscopy. To investigate the oxidation or reduction of the oxide-covered Copper Nanoparticles, a crystal phase analysis using x-ray diffraction was performed. In addition, the sheet resistance of Cu film was measured using a four-point probe method. From this study, it was found that the flash-light sintered Cu nanoink films have a conductivity of 72 Ωm/sq without any damage to the polyimide substrate. Similar nanoinks are expected to be widely used in printed and flexible electronics products in the near future.
Papiya Nandy - One of the best experts on this subject based on the ideXlab platform.
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application of nanomedicine cuprum metallicum as an agent for remediation of an azo dye methyl orange and study its associated antimicrobial activity
International Journal on Environmental Sciences, 2015Co-Authors: Monalisa Chakraborty, Sukhen Das, Rajkumar Manchanda, Ruma Basu, Papiya NandyAbstract:Nanomedicine cuprum metallicum, a commonly available homeopathic drug which has Copper Nanoparticle as a main constituent, has been used to degrade azo dye methyl orange which is mutagenic in nature and is a prime pollutant in the waste water effluents of textile industry. Cuprum metallicum of three different potencies (6C, 30C, 200C) are used to degrade the dye at a particular time interval and also study their effect against gram positive and gram negative bacteria. The result shows that methyl orange can easily be degraded in presence of cuprum metallicum of different potencies and the drug also proved lethal to bacterial strains. Maximum dye degradation and antibacterial activity is observed in presence of 200C potency of the nanomedicine.
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in situ synthesis and antibacterial activity of Copper Nanoparticle loaded natural montmorillonite clay based on contact inhibition and ion release
Colloids and Surfaces B: Biointerfaces, 2013Co-Authors: Biswajoy Bagchi, Subrata Kar, Sumit Dey, Suman Bhandary, Debasis Roy, Tapas Kumar Mukhopadhyay, Sukhen Das, Papiya NandyAbstract:Copper Nanoparticle based clay composite has been synthesized by in situ reduction of a Copper ammonium complex ion and characterized by different analytical instruments. The Copper Nanoparticles were both intercalated and adsorbed on the surface with diameters of 90% after 12h. Cellular membrane damage permeated by direct attachment of the composite and indirect damage caused by released Copper ion are the primary sources of antibacterial action. Cytotoxicity measurements showed minimal adverse effect on the two human cell lines beyond the M.B.C. value for the microorganisms studied. In the present form the clay composite shows good promise for use in therapeutic applications.
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in situ synthesis and antibacterial activity of Copper Nanoparticle loaded natural montmorillonite clay based on contact inhibition and ion release
Colloids and Surfaces B: Biointerfaces, 2013Co-Authors: Biswajoy Bagchi, Suman Bhandary, Tapas Kumar Mukhopadhyay, Papiya NandyAbstract:Abstract Copper Nanoparticle based clay composite has been synthesized by in situ reduction of a Copper ammonium complex ion and characterized by different analytical instruments. The Copper Nanoparticles were both intercalated and adsorbed on the surface with diameters of Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa and Enterococcus faecalis with mortality rates >90% after 12 h. Cellular membrane damage permeated by direct attachment of the composite and indirect damage caused by released Copper ion are the primary sources of antibacterial action. Cytotoxicity measurements showed minimal adverse effect on the two human cell lines beyond the M.B.C. value for the microorganisms studied. In the present form the clay composite shows good promise for use in therapeutic applications.
Haksung Kim - One of the best experts on this subject based on the ideXlab platform.
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Effect of Copper oxide shell thickness on flash light sintering of Copper Nanoparticle ink
RSC Advances, 2017Co-Authors: Hyunjun Hwang, Haksung KimAbstract:In this study, the effect of the thickness of a Copper oxide-shell on flash light sintering of Cu Nanoparticles (NPs) was investigated. The electrical properties of Cu nano-ink films with various oxide-shell thicknesses were examined by measuring the sheet resistance. Furthermore, the amount of PVP in the Cu NP-ink was varied to reduce the Copper oxide-shell efficiently and enhance the flash light sintering of the Cu NPs. Also, to investigate the reduction and sintering phenomena of Cu NPs with respect to the Copper oxide shell thickness, the sheet resistances of the Cu films were measured in real-time using an in situ resistance measuring system during the flash light sintering process. The results of this study established the maximum allowable thickness of the Copper oxide shell that allows flash light sintering and also provided the optimal amount of PVP in Cu nano-ink for a particular Copper oxide shell thickness.
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Copper Nanoparticle multiwalled carbon nanotube composite films with high electrical conductivity and fatigue resistance fabricated via flash light sintering
ACS Applied Materials & Interfaces, 2015Co-Authors: Hyunjun Hwang, Sungjun Joo, Haksung KimAbstract:In this work, multiwalled carbon nanotubes (MWNTs) were employed to improve the conductivity and fatigue resistance of flash light sintered Copper Nanoparticle (NP) ink films. The effect of CNT weight fraction on the flash light sintering and the fatigue characteristics of Cu NP/CNT composite films were investigated. The effect of carbon nanotube length was also studied with regard to enhancing the conductivity and fatigue resistance of flash light sintered Cu NP/CNT composite films. The flash light irradiation energy was optimized to obtain high conductivity Cu NP/CNT composite films. Cu NP/CNT composite films fabricated via optimized flash light irradiation had the lowest resistivity (7.86 μΩ·cm), which was only 4.6 times higher than that of bulk Cu films (1.68 μΩ·cm). It was also demonstrated that Cu NP/CNT composite films had better durability and environmental stability than those of Cu NPs only.
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temperature changes of Copper Nanoparticle ink during flash light sintering
Journal of Materials Processing Technology, 2014Co-Authors: Sunghyeon Park, Wanho Chung, Haksung KimAbstract:Abstract The Copper Nanoparticle ink was coated on polyimide substrates using a doctor blade method. The films thus formed were then sintered by flash light irradiation at room temperature under ambient conditions. The flash light energy was varied from 2 J/cm 2 to 12 J/cm 2 . To measure the temperature change, a non-inverting amplifier circuit with an op-amp and a type-K thermocouple was devised. The sheet resistance change was simultaneously monitored using a Wheatstone bridge circuit. An analytical temperature calculation was conducted, considering the heat transfer phenomena during the flash light irradiation. As the results, the temperature of the Copper Nanoparticle films was reached to (318 °C) in 10 ms at the flash light irradiation energy higher than 12 J/cm 2 and they were melted and fully sintered. The analytical solutions of the temperature profile of Copper Nanoparticles film and polyimide substrate (maximum temperature of Copper Nanoparticles film and polyimide substrates are 279 °C and 140 °C, respectively) in which the latent heats for phase changes of the Copper Nanoparticles and the binder (PVP) were concerned, agrees well with the experimentally measured temperature profiles of them (maximum temperature of Copper Nanoparticles film and polyimide substrates are 318 °C and 135 °C, respectively). The analytical calculation method proposed, could be used to design the flash light sintering variables applicable to various low-temperature flexible substrates.
Hyunjun Hwang - One of the best experts on this subject based on the ideXlab platform.
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Effect of Copper oxide shell thickness on flash light sintering of Copper Nanoparticle ink
RSC Advances, 2017Co-Authors: Hyunjun Hwang, Haksung KimAbstract:In this study, the effect of the thickness of a Copper oxide-shell on flash light sintering of Cu Nanoparticles (NPs) was investigated. The electrical properties of Cu nano-ink films with various oxide-shell thicknesses were examined by measuring the sheet resistance. Furthermore, the amount of PVP in the Cu NP-ink was varied to reduce the Copper oxide-shell efficiently and enhance the flash light sintering of the Cu NPs. Also, to investigate the reduction and sintering phenomena of Cu NPs with respect to the Copper oxide shell thickness, the sheet resistances of the Cu films were measured in real-time using an in situ resistance measuring system during the flash light sintering process. The results of this study established the maximum allowable thickness of the Copper oxide shell that allows flash light sintering and also provided the optimal amount of PVP in Cu nano-ink for a particular Copper oxide shell thickness.
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Copper Nanoparticle multiwalled carbon nanotube composite films with high electrical conductivity and fatigue resistance fabricated via flash light sintering
ACS Applied Materials & Interfaces, 2015Co-Authors: Hyunjun Hwang, Sungjun Joo, Haksung KimAbstract:In this work, multiwalled carbon nanotubes (MWNTs) were employed to improve the conductivity and fatigue resistance of flash light sintered Copper Nanoparticle (NP) ink films. The effect of CNT weight fraction on the flash light sintering and the fatigue characteristics of Cu NP/CNT composite films were investigated. The effect of carbon nanotube length was also studied with regard to enhancing the conductivity and fatigue resistance of flash light sintered Cu NP/CNT composite films. The flash light irradiation energy was optimized to obtain high conductivity Cu NP/CNT composite films. Cu NP/CNT composite films fabricated via optimized flash light irradiation had the lowest resistivity (7.86 μΩ·cm), which was only 4.6 times higher than that of bulk Cu films (1.68 μΩ·cm). It was also demonstrated that Cu NP/CNT composite films had better durability and environmental stability than those of Cu NPs only.
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in situ monitoring of flash light sintering of Copper Nanoparticle ink for printed electronics
Nanotechnology, 2012Co-Authors: Hyunjun Hwang, Wanho ChungAbstract:In this work, a flash-light sintering process for Cu nanoinks was studied. In order to precisely monitor the milliseconds flash-light sintering process, a real-time Wheatstone bridge electrical circuit and a high-rate data acquisition system were used. The effects of several flash-light irradiation conditions (irradiation energy, pulse number, on-time, and off-time) and the effects of the amount of poly(N-vinylpyrrolidone) in the Cu nanoink on the flash-light sintering process were investigated. The microstructures of the sintered Cu films were analyzed by scanning electron microscopy. To investigate the oxidation or reduction of the oxide-covered Copper Nanoparticles, a crystal phase analysis using x-ray diffraction was performed. In addition, the sheet resistance of Cu film was measured using a four-point probe method. From this study, it was found that the flash-light sintered Cu nanoink films have a conductivity of 72 Ωm/sq without any damage to the polyimide substrate. Similar nanoinks are expected to be widely used in printed and flexible electronics products in the near future.