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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.


Related in: MedlinePlus

(a) A schematic illustration of the method used to synthesize C/PANI fibers in a glass reaction pipe with an inner diameter of 500 μm. The two ends of glass tube were sealed with PI tape prior to heating. Free-standing C/PANI fibers were obtained by releasing them from the reaction pipe by an injection of water and air drying. (b–e) Representative FE−SEM micrographs show the synthesized free-standing C/PANI fibers (width ca. 250–300 μm) at low and high magnification.
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f4: (a) A schematic illustration of the method used to synthesize C/PANI fibers in a glass reaction pipe with an inner diameter of 500 μm. The two ends of glass tube were sealed with PI tape prior to heating. Free-standing C/PANI fibers were obtained by releasing them from the reaction pipe by an injection of water and air drying. (b–e) Representative FE−SEM micrographs show the synthesized free-standing C/PANI fibers (width ca. 250–300 μm) at low and high magnification.

Mentions: In addition, a facile one-step, dimensionally confined hydrothermal strategy was employed to fabricate C/PANI fibers (Fig. 4a). A glass pipe with an inner diameter of 0.5 mm was used as the reactor. Solvated C/PANI solution was injected into the glass pipe, which was then sealed at both ends with polyimide (PI) tape and heated to 120 °C for 12 h. Water was then injected into the pipe to delaminate the C/PANI. This process, which depended on the high hydrophobicity of the C/PANI (Fig. 5), released a C/PANI fiber matching the inner pipe geometry. This process was not as applicable to the synthesis of carbon or PANI fibers due to the lower hydrophobicity and lower mechanical strength of those materials. Figure 4b–e show the synthesized free-standing C/PANI fibers at low and high magnification. The fibers have diameters of ca. 250–300 μm. The approximate 50% decrease in diameter relative to the newly released fibers is due to solvent loss and associated shrinkage. This drastic contraction in diameter during the drying process produces strong surface tension forces that result in spontaneous orientation and dense packing of C/PANI along the main axis of the fibers. Fiber diameter and length can be controlled by using a reaction pipe with a predesigned length and inner diameter.


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) A schematic illustration of the method used to synthesize C/PANI fibers in a glass reaction pipe with an inner diameter of 500 μm. The two ends of glass tube were sealed with PI tape prior to heating. Free-standing C/PANI fibers were obtained by releasing them from the reaction pipe by an injection of water and air drying. (b–e) Representative FE−SEM micrographs show the synthesized free-standing C/PANI fibers (width ca. 250–300 μm) at low and high magnification.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: (a) A schematic illustration of the method used to synthesize C/PANI fibers in a glass reaction pipe with an inner diameter of 500 μm. The two ends of glass tube were sealed with PI tape prior to heating. Free-standing C/PANI fibers were obtained by releasing them from the reaction pipe by an injection of water and air drying. (b–e) Representative FE−SEM micrographs show the synthesized free-standing C/PANI fibers (width ca. 250–300 μm) at low and high magnification.
Mentions: In addition, a facile one-step, dimensionally confined hydrothermal strategy was employed to fabricate C/PANI fibers (Fig. 4a). A glass pipe with an inner diameter of 0.5 mm was used as the reactor. Solvated C/PANI solution was injected into the glass pipe, which was then sealed at both ends with polyimide (PI) tape and heated to 120 °C for 12 h. Water was then injected into the pipe to delaminate the C/PANI. This process, which depended on the high hydrophobicity of the C/PANI (Fig. 5), released a C/PANI fiber matching the inner pipe geometry. This process was not as applicable to the synthesis of carbon or PANI fibers due to the lower hydrophobicity and lower mechanical strength of those materials. Figure 4b–e show the synthesized free-standing C/PANI fibers at low and high magnification. The fibers have diameters of ca. 250–300 μm. The approximate 50% decrease in diameter relative to the newly released fibers is due to solvent loss and associated shrinkage. This drastic contraction in diameter during the drying process produces strong surface tension forces that result in spontaneous orientation and dense packing of C/PANI along the main axis of the fibers. Fiber diameter and length can be controlled by using a reaction pipe with a predesigned length and inner diameter.

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.


Related in: MedlinePlus