Yoshiyuki Shibayama
Abstract
Activated carbon fibers (ACFs) are a nanoporous form of carbon with huge specific surface areas caused by a three-dimensional random network of nanographites. Because of nano-size effects, non-bonding π-electron spins emerge on the nanographite. The nanographite random network produces many nanopores ...
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Activated carbon fibers (ACFs) are a nanoporous form of carbon with huge specific surface areas caused by a three-dimensional random network of nanographites. Because of nano-size effects, non-bonding π-electron spins emerge on the nanographite. The nanographite random network produces many nanopores with a mean size of several nanometers and creates a host system for various guest molecules in ACFs. In order to investigate the magnetic properties of nanographite and the superfluidity of 4He restricted in nano-spaces, the magnetization of ACFs and superfluidity of 4He adsorbed in ACFs have been investigated. The magnetization shows an antiferromagnetic interaction between the non-bonding π-electron spins. Near the insulator-metal transition caused by heat treatment of ACFs, spin glass-like disordered magnetism observed. Up to an 4 He coverage of 22.6 μmol/m 2 , no superfluidity is observed due to the strong van der Waals force between 4 He and nanographite. Over 23.7 μmol/m 2 4He coverage, the superfluid transition is observed at approximately Tc ~ 500 mK. Upon increasing the 4 He coverage, the superfluid density increases, but no change in Tc is observed. These observations indicate that the thickness of superfluid films on nanographite is restricted by the slit type pore shape of ACFs. Copyright © 2018 VBRI Press.
Sunita Rattan; Prachi Singhal; Devesh Kumar Avasthi; Ambuj Tripathi
Abstract
Ion implantation is a surface treatment process in which the surface of a sample is bombarded with a beam of energetic dopant ions to implant ions into the matrix of the substrate. In the present work, nanocomposites of poly(3,4-ethylenedioxy thiophene) /poly(4-styrene sulphonate) (PEDOT: PSS) and nanographite ...
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Ion implantation is a surface treatment process in which the surface of a sample is bombarded with a beam of energetic dopant ions to implant ions into the matrix of the substrate. In the present work, nanocomposites of poly(3,4-ethylenedioxy thiophene) /poly(4-styrene sulphonate) (PEDOT: PSS) and nanographite are prepared and subjected to swift heavy ion implantation using the same ion as that of the filler in the nanocomposites. PEDOT: PSS/ nanographite nanocomposites have been synthesized by solution blending method. The prepared PEDOT: PSS/ nanographite nanocomposite films were irradiated with carbon ions (C ion beam, 50 MeV) in fluence range of 3 × 10 10 to 3 × 10 12 ions/cm 2 . The nanocomposite films were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) before and after C ion implantation and were evaluated for their electrical and sensor properties. SEM and XRD studies clearly depict the homogeneous dispersion of nanograhite in polymer matrix along with densification of the polymer nanocomposite. The implanted nanocomposites exhibit better electrical and sensor properties for the detection of nitroaromatics.
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