Carbon-based materials, such as graphene, exhibit interesting physical properties and have been recently investigated in sensing applications. In this paper, a novel technique for glucose concentration correlation with the resonant frequency of a microwave resonator is performed. The resonator exploits the variation of the electrical properties of graphene at radio frequency (RF). The described approach is based on the variation in transmission coefficient resonating frequency of a microstrip ring resonator modified with a graphene film. The graphene film is doctor-bladed on the ring resonator and functionalised in order to detect glucose. When a drop with a given concentration is deposited on the graphene film, the resonance peak is shifted. The graphene film is modelled with a lumped element analysis. Several prototypes are realised on Rogers Kappa substrate and their transmission coefficient measured for different concentrations of glucose. Results show a good correlation between the frequency shift and the concentration applied on the film.
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http://dx.doi.org/10.3390/mi14122163 | DOI Listing |
Materials (Basel)
January 2025
Department of Physics, Changwon National University, Changwon 51140, Republic of Korea.
A mechanically robust flexible transparent conductor with high thermal and chemical stability was fabricated from welded silver nanowire networks (w-Ag-NWs) sandwiched between multilayer graphene (MLG) and polyimide (PI) films. By modifying the gas flow dynamics and surface chemistry of the Cu surface during graphene growth, a highly crystalline and uniform MLG film was obtained on the Cu foil, which was then directly coated on the Ag-NW networks to serve as a barrier material. It was found that the highly crystalline layers in the MLG film compensate for structural defects, thus forming a perfect barrier film to shield Ag NWs from oxidation and sulfurization.
View Article and Find Full Text PDFMolecules
December 2024
College of Mechanical and Electronic Engineering, Tarim University, Alar 843300, China.
Molecules
December 2024
Institute of Materials Science, Kaunas University of Technology, K. Baršausko 59, LT-51423 Kaunas, Lithuania.
This study explores the low-temperature synthesis of graphene using plasma-enhanced chemical vapor deposition (PECVD), emphasizing the optimization of process parameters to achieve controlled growth of pristine and hydrogenated graphene. Graphene films were synthesized at temperatures ranging from 700 °C to as low as 400 °C by varying methane (25-100 sccm) and hydrogen (25-100 sccm) gas flow rates under 10-20 mBar pressures. Raman spectroscopy revealed structural transitions: pristine graphene grown at 700 °C exhibited strong 2D peaks with an I(2D)/I(G) ratio > 2, while hydrogenated graphene synthesized at 500 °C showed increased defect density with an I(D)/I(G) ratio of ~1.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
Department of Chemistry, University of Sherbrooke, 2500, Blvd de l'Université, Sherbrooke, QC J1K 2R1, Canada.
This study delves into the distinctive selective property exhibited by a non-conjugated cholesterol-based polymer, poly(CEM--EHA), in sorting semiconducting single-walled carbon nanotubes (s-SWCNTs) within isooctane. Comprised of 11 repeating units of cholesteryloxycarbonyl-2-hydroxy methacrylate (CEM) and 7 repeating units of 2-ethylhexyl acrylate (EHA), this non-conjugated polymer demonstrates robust supramolecular interactions across the sp surface structure of carbon nanotubes and graphene. When coupled with the Double Liquid-Phase Extraction (DLPE) technology, the polymer effectively segregates s-SWCNTs into the isooctane phase (nonpolar) while excluding metallic SWCNTs (m-SWCNTs) in the water phase (polar).
View Article and Find Full Text PDFSmall Methods
January 2025
School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 401331, China.
Bilayer graphene ribbons (GRs) hold great promise for the fabrication of next-generation nanodevices, thanks to unparalleled electronic properties, especially the tunable bandgap in association with twist angle, ribbon width, edge structure, and interlayer coupling. A common challenge in manufacturing bilayer GRs via templated chemical vapor deposition (CVD) approach is uncontrollable dewetting of micro- and nano-scaled patterned metal substrates. Herein, a confined CVD synthetic strategy of bilayer GR arrays is proposed, by utilizing the bifunctional Ni as a buffered adhesion layer to regulate the anisotropic dewetting of metal film in the V-groove and as a carbon-dissolution regulated metal to initiate the bilayer nucleation.
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