Publications by authors named "Jong Seok Woo"

This study aimed to investigate the effect of impregnation pressure on the decrease in porosity of impregnated bulk graphite. The correlation between pitch impregnation behavior and the pore sizes of the bulk graphite block was studied to determine the optimal impregnation pressure. The densities and porosities of the bulk graphite before and after pitch impregnation under various pressures between 10 and 50 bar were evaluated based on the Archimedes method and a mercury porosimeter.

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A carbonized cellulose/single-walled carbon nanotube composite film (cell/SWCNT) was prepared with well-dispersed cellulose/SWCNT doped in N-methylmorpholine N-oxide (NMMO) monohydrate. After carbonization at 400 °C, the SWCNT content at electrical threshold of the cell/SWCNT nanocomposite decreased from 2 wt% to 1 wt%, and the electrical conductivity of the cell/SWCNT(1 wt%) nanocomposite (0.6 S cm) increased by more than 6 orders of magnitude compared to that of pure carbonized cellulose (1.

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Dispersion of nanocarbon materials in liquid media, via solution processing such as spraying, printing, spinning, etc. is one of the prerequisites for practical applications. Here we report that water-dispersible single-walled carbon nanotubes (SWCNTs) were prepared through successive treatments with chlorosulfuric acid (CSA)/HO and N-methylmorpholine N-oxide (NMO) monohydrate.

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Most synthetic processes of metallic nanostructures were assisted by organic/inorganic or polymeric materials to control their shapes to one-dimension or two-dimension. However, these additives have to be removed after synthesis of metal nanostructures for applications. Here we report a straightforward method for the low-temperature and additive-free synthesis of nanobelt-like silver nanostructures templated by nanocarbon (NC) materials via bio-inspired shape control by introducing supramolecular 2-ureido-4[1H]pyrimidinone (UPy) groups into the NC surface.

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Article Synopsis
  • Superhydrophobic surfaces with conducting nanomaterials can be created using a simple screen printing method featuring carbon nanotube-based pastes, allowing for various applications like nonwetting and electrical conductivity.
  • The addition of a PDMS-PEG copolymer to the conducting paste enhances both the printability and hydrophobicity of the printed surfaces, achieving water contact angles greater than 150° and low contact angle hysteresis.
  • These surfaces also exhibit sticky characteristics to transport droplets, serve as filters for oil/water separation, and can be used to study liquid evaporation in conductive thin-film heaters.
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Atomically thin and two-dimensional graphene oxide (GO) is a very fascinating material because of its functional groups, high transparency, and solution processability. Here we show that highly oxidized GO (HOGO) nanosheets serve as an effective interfacial modifier of transparent conducting films with one-dimensional (1D) silver nanowires (AgNWs) and single-walled carbon nanotubes (SWCNTs). Optically transparent and small-sized GO nanosheets, with minimal sp(2) domains, were successfully fabricated by step-wise oxidation and exfoliation of graphite.

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A method of microwave sintering that is mediated by carbon nanotubes (CNTs) has been developed to obtain high-conductivity Ag patterns on the top of heat-sensitive plastic substrates within a short time. The Ag patterns are printed on CNTs formed on plastic substrates and rapidly heated to a great extent by the heat transferred from the microwave-heated CNTs. The conductivity of the microwave-sintered Ag patterns reaches ∼39% that of bulk Ag within 1 s without substrate deformation.

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Article Synopsis
  • Researchers developed highly conductive polymer-composite fibers using carbon nanotubes and silver nanowires without any dispersants, achieving an impressive electrical conductivity of ~1.5 × 10(5) S m(-1).
  • This process involved mixing polyvinyl alcohol in dimethylsulfoxide with carbon nanotube paste and aqueous silver nanowire dispersion, utilizing hydrogen-bonding networks for stability.
  • The resulting fibers have potential applications in smart textiles, including interconnectors for LEDs, flexible heaters, and touch-sensitive gloves.
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Layered materials must be exfoliated and dispersed in solvents for diverse applications. Usually, highly energetic probe sonication may be considered to be an unfavourable method for the less defective exfoliation and dispersion of layered materials. Here we show that judicious use of ultrasonic cavitation can produce exfoliated transition metal dichalcogenide nanosheets extraordinarily dispersed in non-toxic solvent by minimising the sonolysis of solvent molecules.

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Modulation of the junction resistance between metallic nanowires is a crucial factor for high performance of the network-structured conducting film. Here, we show that under current flow, silver nanowire (AgNW) network films can be stabilised by minimizing the Joule heating at the NW-NW junction assisted by in-situ interconnection with a small amount (less than 3 wt%) of single-walled carbon nanotubes (SWCNTs). This was achieved by direct deposition of AgNW suspension containing SWCNTs functionalised with quadruple hydrogen bonding moieties excluding dispersant molecules.

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Microwave flash annealing dramatically enhances the environmental stability of AuCl3-doped single-walled carbon nanotube (SWCNT) films on plastic substrates using fast microwave nanoheating to produce a large temperature difference between the films and the substrates. Within one second, the microwave nanoheating rapidly caused thermal decomposition of AuCl3 dopants as well as simultaneous embedding of SWCNTs in the substrate, without deforming it. The hygroscopic Cl atoms were partially desorbed from the SWCNTs by rapid thermal decomposition, and the embedded substrate surface acted as a passivation layer, which synergistically contributed to the stability of the doped and annealed SWCNTs.

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The dispersant-free fabrication of highly conducting pastes based on organic solvents with nanocarbon materials such as carbon nanotubes and graphene nanoplatelets has been hindered by severe agglomeration. Here we report a straightforward method for fabricating nanocarbon suspensions with >10% weight concentrations in absence of organic dispersants. The method involves introducing supramolecular quadruple hydrogen-bonding motifs into the nanocarbon materials without sacrificing the electrical conductivity.

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Synopsis of recent research by authors named "Jong Seok Woo"

  • - Jong Seok Woo's research primarily focuses on the synthesis and functionalization of nanocarbon materials, particularly single-walled carbon nanotubes (SWCNTs) and graphene, to enhance their electrical conductivity and versatility for applications in flexible and wearable electronics.
  • - His studies have led to the development of novel methods for the dispersion and integration of nanocarbon materials in various matrices, enabling high-performance composites and conductive films with significant improvements in stability and conductivity.
  • - Recent findings emphasize the importance of optimizing processing conditions, such as impregnation pressure and microwave sintering, to achieve desirable properties in nanocarbon-based materials, thereby facilitating their use in advanced electronic applications and smart materials.

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