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Full-Text Articles in Engineering
Formation And Processability Of Liquid Crystalline Dispersion Graphene Oxide, Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Konstantin Konstantinov, Joselito M. Razal, Simon E. Moulton, Gordon G. Wallace
Formation And Processability Of Liquid Crystalline Dispersion Graphene Oxide, Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Konstantin Konstantinov, Joselito M. Razal, Simon E. Moulton, Gordon G. Wallace
Gordon Wallace
Rational control over the formation and processability, and consequently final properties of graphene oxide liquid crystalline dispersions has been a long-standing goal in the development of bottom-up device fabrication processes. Here we report, the principal conditions through which such levels of control can be exercised to fine-tune dispersion properties for further processing.
Aqueous Dispersions Of Reduced Graphene Oxide And Multi Wall Carbon Nanotubes For Enhanced Glucose Oxidase Bioelectrode Performance, Willo Grosse, Joffrey Champavert, Sanjeev Gambhir, Gordon G. Wallace, Simon E. Moulton
Aqueous Dispersions Of Reduced Graphene Oxide And Multi Wall Carbon Nanotubes For Enhanced Glucose Oxidase Bioelectrode Performance, Willo Grosse, Joffrey Champavert, Sanjeev Gambhir, Gordon G. Wallace, Simon E. Moulton
Gordon Wallace
Aqueous dispersions of reduced graphene oxide (rGO) and multi walled carbon nanotubes (MWCNT) were fabricated through a modified chemical reduction method. The significant advantage of the method developed here is the omission of any stabilising compound or organic solvent to obtain stable rGO-MWCNT dispersions. Significantly biological entities, in this case the enzyme glucose oxidase (GOx), can be successfully incorporated into the dispersion. These dispersions were characterised using XPS, SEM, zeta potential and particle size measurements which showed that the dispersion stability is not sacrificed with the addition of GOx, and significantly, the electrical properties of the rGO and MWCNTs are …
Fabrication Of Graphene Electrodes By Electrophoretic Deposition And Their Synergistic Effects With Pedot And Platinum, Widsanusan Chartarrayawadee, Simon E. Moulton, Chee O. Too, Gordon G. Wallace
Fabrication Of Graphene Electrodes By Electrophoretic Deposition And Their Synergistic Effects With Pedot And Platinum, Widsanusan Chartarrayawadee, Simon E. Moulton, Chee O. Too, Gordon G. Wallace
Gordon Wallace
This research presents a useful electrophoretic deposition (EPD) technique for electrode fabrication from an aqueous colloidal solution of graphene to produce graphene electrodes by the deposition of graphene on to indium-tin oxide (ITO) coated glass. Resultant graphene electrodes are composited with conducting polymer (PEDOT), and platinum nanoparticles, to investigate their synergistic effects. Firstly, PEDOT is composited with graphene by electropolymerization on to the graphene layer. The graphene/PEDOT electrodes demonstrate an improvement in electrochemical response in tetrabutylammonium perchlorate/ acetonitrile solution. Secondly, graphene electrodes are composited with platinum by EPD of platinum nanoparticles on to the graphene layer. The resultant graphene/platinum electrodes …
Facile Synthesis Of Reduced Graphene Oxide/Mwnts Nanocomposite Supercapacitor Materials Tested As Electrophoretically Deposited Films On Glassy Carbon Electrodes, Widsanusan Chartarrayawadee, Simon E. Moulton, Chee O. Too, Byung C. Kim, Rao Yepuri, Anthony C. Romeo, Gordon G. Wallace
Facile Synthesis Of Reduced Graphene Oxide/Mwnts Nanocomposite Supercapacitor Materials Tested As Electrophoretically Deposited Films On Glassy Carbon Electrodes, Widsanusan Chartarrayawadee, Simon E. Moulton, Chee O. Too, Byung C. Kim, Rao Yepuri, Anthony C. Romeo, Gordon G. Wallace
Gordon Wallace
This paper reports on a facile synthesis method for reduced graphene oxide (rGO)/multi-walled carbon nanotubes (MWNTs) nanocomposites. The initial step involves the use of graphene oxide to disperse the MWNTs, with subsequent reduction of the resultant graphene oxide/MWNTs composites using l-ascorbic acid (LAA) as a mild reductant. Reduction by LAA preserves the interaction between the rGO sheets and MWNTs. The dispersion-containing rGO/MWNTs composites was characterized and electrophoretically deposited anodically onto glassy carbon electrodes to form high surface area films for capacitance testing. Pseudo capacitance peaks were observed in the rGO/MWNTs composite electrodes, resulting in superior performance with capacitance values up …
Scalable One-Step Wet-Spinning Of Graphene Fibers And Yarns From Liquid Crystalline Dispersions Of Graphene Oxide: Towards Multifunctional Textiles, Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Roderick L. Shepherd, Jun Chen, Sima Aminorroaya-Yamini, Konstantin Konstantinov, Andrew I. Minett, Joselito M. Razal, Gordon G. Wallace
Scalable One-Step Wet-Spinning Of Graphene Fibers And Yarns From Liquid Crystalline Dispersions Of Graphene Oxide: Towards Multifunctional Textiles, Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Roderick L. Shepherd, Jun Chen, Sima Aminorroaya-Yamini, Konstantin Konstantinov, Andrew I. Minett, Joselito M. Razal, Gordon G. Wallace
Gordon Wallace
Key points in the formation of liquid crystalline (LC) dispersions of graphene oxide (GO) and their processability via wet-spinning to produce long lengths of micrometer-dimensional fibers and yarns are addressed. Based on rheological and polarized optical microscopy investigations, a rational relation between GO sheet size and polydispersity, concentration, liquid crystallinity, and spinnability is proposed, leading to an understanding of lyotropic LC behavior and fiber spinnability. The knowledge gained from the straightforward formulation of LC GO "inks" in a range of processable concentrations enables the spinning of continuous conducting, strong, and robust fibers at concentrations as low as 0.075 wt%, eliminating …
Carbon Nanotube-Reduced Graphene Oxide Composites For Thermal Energy Harvesting Applications, Mark S. Romano, Na Li, Dennis Antiohos, Joselito M. Razal, Andrew Nattestad, Stephen Beirne, Shaoli Fang, Yongsheng Chen, Rouhollah Jalili, Gordon G. Wallace, Ray Baughman, Jun Chen
Carbon Nanotube-Reduced Graphene Oxide Composites For Thermal Energy Harvesting Applications, Mark S. Romano, Na Li, Dennis Antiohos, Joselito M. Razal, Andrew Nattestad, Stephen Beirne, Shaoli Fang, Yongsheng Chen, Rouhollah Jalili, Gordon G. Wallace, Ray Baughman, Jun Chen
Gordon Wallace
By controlling the SWNT-rGO electrode composition and thickness to attain the appropriate porosity and tortuosity, the electroactive surface area is maximized while rapid diffusion of the electrolyte through the electrode is maintained. This leads to an increase in exchange current density between the electrode and electrolyte which results in enhanced thermocell performance.
Organic Solvent-Based Graphene Oxide Liquid Crystals: A Facile Route Toward The Next Generation Of Self-Assembled Layer-By-Layer Multifunctional 3d Architectures, Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Konstantin Konstantinov, Simon E. Moulton, Joselito M. Razal, Gordon G. Wallace
Organic Solvent-Based Graphene Oxide Liquid Crystals: A Facile Route Toward The Next Generation Of Self-Assembled Layer-By-Layer Multifunctional 3d Architectures, Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Konstantin Konstantinov, Simon E. Moulton, Joselito M. Razal, Gordon G. Wallace
Gordon Wallace
We introduce soft self-assembly of ultralarge liquid crystalline (LC) graphene oxide (GO) sheets in a wide range of organic solvents overcoming the practical limitations imposed on LC GO processing in water. This expands the number of known solvents which can support amphiphilic self-assembly to ethanol, acetone, tetrahydrofuran, N-dimethylformamide, N-cyclohexyl-2-pyrrolidone, and a number of other organic solvents, many of which were not known to afford solvophobic self-assembly prior to this report. The LC behavior of the as-prepared GO sheets in organic solvents has enabled us to disperse and organize substantial amounts of aggregate-free single-walled carbon nanotubes (SWNTs, up to 10 wt …
Manganosite-Microwave Exfoliated Graphene Oxide Composites For Asymmetric Supercapacitor Device Applications, Dennis Antiohos, Kanlaya Pingmuang, Mark Romano, Stephen Beirne, Tony C. Romeo, Phil Aitchison, Andrew I. Minett, Gordon G. Wallace, Sukon Phanichphant, Jun Chen
Manganosite-Microwave Exfoliated Graphene Oxide Composites For Asymmetric Supercapacitor Device Applications, Dennis Antiohos, Kanlaya Pingmuang, Mark Romano, Stephen Beirne, Tony C. Romeo, Phil Aitchison, Andrew I. Minett, Gordon G. Wallace, Sukon Phanichphant, Jun Chen
Gordon Wallace
Graphene based materials coupled with transition metal oxides are promising electrode materials in asymmetric supercapacitors owing to their unique properties which include high surface area, good chemical stability, electrical conductivity, abundance, and lower cost profile over time. In this paper a composite material consisting of graphene oxide exfoliated with microwave radiation (mw rGO), and manganosite (MnO) is synthesised in order to explore their potential as an electrode material. The composite material was characterised by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to explore …
Covalently Linked Biocompatible Graphene/Polycaprolactone Composites For Tissue Engineering, Sepidar Sayyar, Eoin Murray, Brianna C. Thompson, Sanjeev Gambhir, David L. Officer, Gordon G. Wallace
Covalently Linked Biocompatible Graphene/Polycaprolactone Composites For Tissue Engineering, Sepidar Sayyar, Eoin Murray, Brianna C. Thompson, Sanjeev Gambhir, David L. Officer, Gordon G. Wallace
Gordon Wallace
Two synthesis routes to graphene/polycaprolactone composites are introduced and the properties of the resulting composites compared. In the first method, mixtures are produced using solution processing of polycaprolactone and well dispersed, chemically reduced graphene oxide and in the second, an esterification reaction covalently links polycaprolactone chains to free carboxyl groups on the graphene sheets. This is achieved through the use of a stable anhydrous dimethylformamide dispersion of graphene that has been highly chemically reduced resulting in mostly peripheral ester linkages. The resulting covalently linked composites exhibit far better homogeneity and as a result, both Young's modulus and tensile strength more …
Preparation And Characterisation Of Graphene Composite Hydrogels, Nicholas J. Whiteside, Gordon G. Wallace, Marc In Het Panhuis
Preparation And Characterisation Of Graphene Composite Hydrogels, Nicholas J. Whiteside, Gordon G. Wallace, Marc In Het Panhuis
Gordon Wallace
Stable dispersions containing graphene and gellan gum are used to form composite films. Incorporation of graphene into the gellan gum matrix results in mechanical reinforcement and electrical conductivity at low and high graphene loading fractions, respectively. Graphene-containing gellan gum hydrogel films are prepared by immersion of composite films in Ca2+ cross-linking solutions. The resulting hydrogels are electrically conducting and exhibit reinforcement compared to the corresponding gellan gum hydrogels. 2013 Elsevier B.V.
The Effect Of Reduced Graphene Oxide Addition On The Superconductivity Of Mgb2, K S. B De Silva, S Gambhir, Xiaolin Wang, X Xu, W X. Li, David L. Officer, D Wexler, G G. Wallace, S. X. Dou
The Effect Of Reduced Graphene Oxide Addition On The Superconductivity Of Mgb2, K S. B De Silva, S Gambhir, Xiaolin Wang, X Xu, W X. Li, David L. Officer, D Wexler, G G. Wallace, S. X. Dou
Gordon Wallace
Reduced graphene oxide (rGO) and highly reduced chemically converted graphene (ICCO) samples were prepared under different processing condition! and were doped into MgBz by a diffusion process at 800 °C for 10 houn. It was demonstrated that a small addition rCCG can significantly improve the supcn;onducting properties of MgBz. Doping of M8B2 with 1 mol% of rCCG resulted in a Ie of 5.45 X lOS A cm-2 at 20 K in self-fields, which il nearly 32% improvement over that of the undopcd sample. This is a significant improvement as most carbon sources adversely affect the Ie performance: at the zero …
Carbon Nanotube/Graphene Nanocomposite As Efficient Counter Electrodes In Dye-Sensitized Solar Cells, Josef Velten, Attila J. Mozer, Dan Li, David Officer, G G. Wallace, Ray Baughman, A Zakhidov
Carbon Nanotube/Graphene Nanocomposite As Efficient Counter Electrodes In Dye-Sensitized Solar Cells, Josef Velten, Attila J. Mozer, Dan Li, David Officer, G G. Wallace, Ray Baughman, A Zakhidov
Gordon Wallace
We demonstrated the replacement of the Pt catalyst normally used in the counter electrode of a dye-sensitized solar cell (DSSC) by a nanocomposite of dry spun carbon multi-walled nanotube (MWNT) sheets with graphene flakes (Gr-F). The effectiveness of this counter electrode on the reduction of the triiodide in the iodide/triiodide redox (I−/I− 3 ) redox reaction was studied in parallel with the use of the dry spun carbon MWNT sheets alone and graphene flakes used independent of each other. This nanocomposite deposited onto fluorinated tin-oxide-coated glass showed improved catalytic behavior and power conversion efficiency (7.55%) beyond the use of the …