We describe the first preparation of polymer-supported pristine graphene thin films with dramatically different electrical conductivities on the top and bottom surfaces. Pyrene-functional stabilizers based on polystyrene or poly(methyl methacrylate) were first synthesized by copolymerization of their monomers with 1-pyrenemethyl methacrylate. Stable dispersions of pristine graphene nanosheets were prepared by sonication of graphite in chloroform solutions of the pyrene-functional copolymers. Vacuum filtration of the polymer-stabilized graphene dispersions through a porous PTFE filter produces films with an internal gradient in nanosheet concentration. This gradient graphene concentration results in an electrically conductive, graphene-rich surface on one side of the composite film and a nonconductive, polymer-rich surface on its other side. Electrical conductivities ranging from 60 to 194 S/m are measured on the graphene-rich surface, which are among the highest conductivities reported for pristine graphene/polymer composites. Through scanning electron microscopy and secondary ion mass spectrometry characterization, these films were found to contain three distinct layers: a polymer-rich top surface, a transition layer with a gradient in nanosheet concentration, and a buckypaper-like bottom layer consisting of densely packed, highly oriented graphene nanosheets. The gradient structure of these films and their Janus-like electrical conductivity has potential applications in graded coatings for radiofrequency and optical devices.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acsami.6b09646 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Advancing Graphene Synthesis: Low-Temperature Growth and Hydrogenation Mechanisms Using Plasma-Enhanced Chemical Vapor Deposition.
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 PDFFacile synthesis of reduced graphene oxide/carbon/calcium alginate aerogel for the removal of pharmaceutical pollutants.
Int J Biol Macromol
January 2025
Department of Environment, Faculty of Environmental Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
Pharmaceuticals are the new emerging challenge pollutants to removal from the aquatic environments. In this study, a series of reduced graphene oxide/carbon/calcium alginate (rGO/C/CA) aerogel was fabricated using an environmentally friendly freeze-drying method. The surface properties including surface textures, elemental contents, crystal structures, and functional groups of rGO/C/CA aerogel were investigated.
View Article and Find Full Text PDFTuning of Water Vapor Permeability in 2D Nanocarbon-Based Polypropylene Composite Membranes.
Nanomaterials (Basel)
December 2024
Foundation for Research and Technology-Hellas (FORTH), Institute of Chemical Engineering Sciences (ICE-HT), Stadiou Str., GR-265 04 Rio-Patras, Greece.
This work focuses on the incorporation of 2D carbon nanomaterials, such as graphene oxide (GO), reduced graphene oxide (rGO) and graphene nanoplatelets (GNPs), into polypropylene (PP) via melt mixing. The addition of these 2D carbon nanostructured networks offers a novel approach to enhancing/controlling the water vapor permeable capabilities of PP composite membranes, widely used in industrial applications, such as technical (building roof membranes) or medical (surgical gowns) textiles. The study investigates how the dispersion and concentration of these graphene nanomaterials within the PP matrix influence the microstructure and water vapor permeability (WVP) performance.
View Article and Find Full Text PDFJanus graphene nanoribbons with localized states on a single zigzag edge.
Nature
January 2025
Department of Chemistry, National University of Singapore, Singapore, Singapore.
Topological design of π electrons in zigzag-edged graphene nanoribbons (ZGNRs) leads to a wealth of magnetic quantum phenomena and exotic quantum phases. Symmetric ZGNRs typically show antiferromagnetically coupled spin-ordered edge states. Eliminating cross-edge magnetic coupling in ZGNRs not only enables the realization of a class of ferromagnetic quantum spin chains, enabling the exploration of quantum spin physics and entanglement of multiple qubits in the one-dimensional limit, but also establishes a long-sought-after carbon-based ferromagnetic transport channel, pivotal for ultimate scaling of GNR-based quantum electronics.
View Article and Find Full Text PDFApplication of Hydrogenated Graphitic Supports in Electrocatalysts: Effects on Carbon Support Surface Chemistry, Nanoparticle Growth, and Electrocatalytic Activity.
ACS Appl Mater Interfaces
January 2025
Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada.
One of the key technical challenges before the widespread adoption of proton exchange membrane fuel cells (PEMFCs) is increasing the durability of the platinum catalyst layer to meet a target of 8000 operating hours with only a 10% loss of performance. Carbon corrosion, one of the primary mechanisms of degradation in fuel cells, has attracted attention from researchers interested in solving the durability problem. As such, the development of catalyst supports to avoid this issue has been a focus in recent years, with interest in hydrophobic supports such as highly graphitized carbons.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!