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Highly Omnidirectional and Frequency Controllable Carbon/Polyaniline-based 2D and 3D Monopole Antenna.

Shin KY, Kim M, Lee JS, Jang J - Sci Rep (2015)

Bottom Line: Solvated C/PANI was synthesized by low-temperature interfacial polymerization, during which strong π-π interactions between graphene and the quinoid rings of PANI resulted in an expanded PANI conformation with enhanced crystallinity and improved mechanical and electrical properties.These antennas attained high peak gain (3.60 dBi), high directivity (3.91 dBi) and radiation efficiency (92.12%) relative to 2D monopole antenna.These improvements were attributed the high packing density and aspect ratios of C/PANI fibers and the removal of the flexible substrate.

View Article: PubMed Central - PubMed

Affiliation: World Class University program of Chemical Convergence for Energy &Environment, School of Chemical and Biological Engineering, Seoul National University, 151-742, Korea.

ABSTRACT
Highly omnidirectional and frequency controllable carbon/polyaniline (C/PANI)-based, two- (2D) and three-dimensional (3D) monopole antennas were fabricated using screen-printing and a one-step, dimensionally confined hydrothermal strategy, respectively. Solvated C/PANI was synthesized by low-temperature interfacial polymerization, during which strong π-π interactions between graphene and the quinoid rings of PANI resulted in an expanded PANI conformation with enhanced crystallinity and improved mechanical and electrical properties. Compared to antennas composed of pristine carbon or PANI-based 2D monopole structures, 2D monopole antennas composed of this enhanced hybrid material were highly efficient and amenable to high-frequency, omnidirectional electromagnetic waves. The mean frequency of C/PANI fiber-based 3D monopole antennas could be controlled by simply cutting and stretching the antenna. These antennas attained high peak gain (3.60 dBi), high directivity (3.91 dBi) and radiation efficiency (92.12%) relative to 2D monopole antenna. These improvements were attributed the high packing density and aspect ratios of C/PANI fibers and the removal of the flexible substrate. This approach offers a valuable and promising tool for producing highly omnidirectional and frequency-controllable, carbon-based monopole antennas for use in wireless networking communications on industrial, scientific, and medical (ISM) bands.

No MeSH data available.


(a) Fabrication of conductive films on flexible substrates via screenprinting and a top-view schematic of various 2D monopole antennas with an SMA connector. Optical and FE−SEM micrographs show the surface morphology of (b) carbon, (c) PANI, and (d) C/PANI-based straight lines (ca. 500 μm × ca. 30 mm). (e) Raman spectra of carbon, PANI, and C/PANI thin films. Raman samples were prepared by screen-printing three conductive inks onto a Si wafer.
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f1: (a) Fabrication of conductive films on flexible substrates via screenprinting and a top-view schematic of various 2D monopole antennas with an SMA connector. Optical and FE−SEM micrographs show the surface morphology of (b) carbon, (c) PANI, and (d) C/PANI-based straight lines (ca. 500 μm × ca. 30 mm). (e) Raman spectra of carbon, PANI, and C/PANI thin films. Raman samples were prepared by screen-printing three conductive inks onto a Si wafer.

Mentions: Solvated C/PANI in m-cresol/chloroform has been synthesized via low-temperature interfacial polymerization with dedoping and redoping processes2425. In this experiment, this strategy was employed, using the polymer solution as a conductive ink in screen printing. This allowed the fabrication of 2D antennas. The procedure used to create C/PANI line patterns on a flexible substrate by screenprinting and a schematic structure of a 2D C/PANI-based monopole antenna are shown in Fig. 1a. The attached mask on photo paper formed an open mesh area that allowed the conductive ink to form a sharp-edged image as it transferred to the substrate. In this way, straight-line patterns (30 mm × 500 μm) were easily fabricated on photo paper. PANI thin films have been obtained by interfacial polymerization without carbon. After, a carbon thin film can be fabricated using graphene oxide (GO) ink that is then reduced by hydrazine vapor26272829. The optical and FE−SEM micrographs in Fig. 1b,c, respectively, show that carbon thin film exhibited a wrinkled and silk-like two-dimensional morphology that was on the micrometer scale. PANI was uniformly polymerized on the surface of the graphene sheets, and the average thickness of the hybrid thin film was assumed to be ca. 2.16 μm (Fig. S1). Furthermore, the pattern obtained with carbon and C/PANI is clearer than that obtained with PANI. This may result from the effects of graphene grains on the polymer domain structure (Fig. 1d). In other words, stacks of large-domain, planar graphene structures resulted in high-resolution patterning in the overlaying C/PANI thin film.


Highly Omnidirectional and Frequency Controllable Carbon/Polyaniline-based 2D and 3D Monopole Antenna.

Shin KY, Kim M, Lee JS, Jang J - Sci Rep (2015)

(a) Fabrication of conductive films on flexible substrates via screenprinting and a top-view schematic of various 2D monopole antennas with an SMA connector. Optical and FE−SEM micrographs show the surface morphology of (b) carbon, (c) PANI, and (d) C/PANI-based straight lines (ca. 500 μm × ca. 30 mm). (e) Raman spectra of carbon, PANI, and C/PANI thin films. Raman samples were prepared by screen-printing three conductive inks onto a Si wafer.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4559896&req=5

f1: (a) Fabrication of conductive films on flexible substrates via screenprinting and a top-view schematic of various 2D monopole antennas with an SMA connector. Optical and FE−SEM micrographs show the surface morphology of (b) carbon, (c) PANI, and (d) C/PANI-based straight lines (ca. 500 μm × ca. 30 mm). (e) Raman spectra of carbon, PANI, and C/PANI thin films. Raman samples were prepared by screen-printing three conductive inks onto a Si wafer.
Mentions: Solvated C/PANI in m-cresol/chloroform has been synthesized via low-temperature interfacial polymerization with dedoping and redoping processes2425. In this experiment, this strategy was employed, using the polymer solution as a conductive ink in screen printing. This allowed the fabrication of 2D antennas. The procedure used to create C/PANI line patterns on a flexible substrate by screenprinting and a schematic structure of a 2D C/PANI-based monopole antenna are shown in Fig. 1a. The attached mask on photo paper formed an open mesh area that allowed the conductive ink to form a sharp-edged image as it transferred to the substrate. In this way, straight-line patterns (30 mm × 500 μm) were easily fabricated on photo paper. PANI thin films have been obtained by interfacial polymerization without carbon. After, a carbon thin film can be fabricated using graphene oxide (GO) ink that is then reduced by hydrazine vapor26272829. The optical and FE−SEM micrographs in Fig. 1b,c, respectively, show that carbon thin film exhibited a wrinkled and silk-like two-dimensional morphology that was on the micrometer scale. PANI was uniformly polymerized on the surface of the graphene sheets, and the average thickness of the hybrid thin film was assumed to be ca. 2.16 μm (Fig. S1). Furthermore, the pattern obtained with carbon and C/PANI is clearer than that obtained with PANI. This may result from the effects of graphene grains on the polymer domain structure (Fig. 1d). In other words, stacks of large-domain, planar graphene structures resulted in high-resolution patterning in the overlaying C/PANI thin film.

Bottom Line: Solvated C/PANI was synthesized by low-temperature interfacial polymerization, during which strong π-π interactions between graphene and the quinoid rings of PANI resulted in an expanded PANI conformation with enhanced crystallinity and improved mechanical and electrical properties.These antennas attained high peak gain (3.60 dBi), high directivity (3.91 dBi) and radiation efficiency (92.12%) relative to 2D monopole antenna.These improvements were attributed the high packing density and aspect ratios of C/PANI fibers and the removal of the flexible substrate.

View Article: PubMed Central - PubMed

Affiliation: World Class University program of Chemical Convergence for Energy &Environment, School of Chemical and Biological Engineering, Seoul National University, 151-742, Korea.

ABSTRACT
Highly omnidirectional and frequency controllable carbon/polyaniline (C/PANI)-based, two- (2D) and three-dimensional (3D) monopole antennas were fabricated using screen-printing and a one-step, dimensionally confined hydrothermal strategy, respectively. Solvated C/PANI was synthesized by low-temperature interfacial polymerization, during which strong π-π interactions between graphene and the quinoid rings of PANI resulted in an expanded PANI conformation with enhanced crystallinity and improved mechanical and electrical properties. Compared to antennas composed of pristine carbon or PANI-based 2D monopole structures, 2D monopole antennas composed of this enhanced hybrid material were highly efficient and amenable to high-frequency, omnidirectional electromagnetic waves. The mean frequency of C/PANI fiber-based 3D monopole antennas could be controlled by simply cutting and stretching the antenna. These antennas attained high peak gain (3.60 dBi), high directivity (3.91 dBi) and radiation efficiency (92.12%) relative to 2D monopole antenna. These improvements were attributed the high packing density and aspect ratios of C/PANI fibers and the removal of the flexible substrate. This approach offers a valuable and promising tool for producing highly omnidirectional and frequency-controllable, carbon-based monopole antennas for use in wireless networking communications on industrial, scientific, and medical (ISM) bands.

No MeSH data available.