Controlled Nanofabrication of Uniform Continuous Graphene Oxide/Polyacrylonitrile Nanofibers for Templated Carbonization

2019 ◽  
Vol 7 (4) ◽  
Author(s):  
Dimitry Papkov ◽  
Alexander Goponenko ◽  
Owen C. Compton ◽  
Zhi An ◽  
SonBinh T. Nguyen ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Composite Nanofibers ◽  
Polymer Concentration ◽  
Building Blocks ◽  
Processing Parameters ◽  
Solid Content ◽  
Graphene Oxides ◽  
Neat Polymer ◽  
Before And After ◽  
Nanoparticle Sizes

Abstract Graphene and graphene oxide attract rapidly growing interest as prospective building blocks for nanotechnology applications and composites. Recently, we showed that a small amount of graphene oxide produced significant templating effects on the structure of continuous carbon nanofibers (CNFs). However, the produced nanofibers had significant nonuniformities that could be detrimental to their mechanical properties. Controlled nanofabrication is critical for obtaining uniform, high-quality nanofibers with tunable diameters and properties. Here, we analyze the effects of graphene oxide type, concentration, and processing parameters on the morphology of continuous graphene oxide/polyacrylonitrile nanofibers produced by electrospinning. Four types of graphene oxides with different average nanoparticle sizes were examined, and the effects of electric field and polymer concentration on nanofiber diameters were analyzed. Good-quality nanofibers were produced with up to 2 wt % graphene oxide in polyacrylonitrile. Uniform nanofibers were obtained for solid content above 9 wt % in dimethylformamide (DMF). Composite nanofibers containing graphene oxide nanoparticles exhibited reduced diameters throughout the polyacrylonitrile concentration range before and after carbonization compared to nanofibers prepared from neat polymer. The obtained results open up a pathway for controlled nanofabrication of uniform CNFs with improved structure for a variety of structural and functional applications.

scholarly journals Characteristics of Graphene Oxide Films Reduced by Using an Atmospheric Plasma System

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 802 ◽  
Author(s):  
Chii-Rong Yang ◽  
Shih-Feng Tseng ◽  
Yu-Ting Chen
Keyword(s):  
Graphene Oxide ◽  
Sheet Resistance ◽  
Functional Groups ◽  
Pyrolytic Graphite ◽  
Chemical Oxidation ◽  
Atmospheric Plasma ◽  
Graphene Oxides ◽  
Plasma Irradiation ◽  
Before And After ◽  
Bond Peak

The chemical oxidation method can be used to mass-produce graphene oxides (GOs) from highly oriented pyrolytic graphite. However, numerous oxygen-containing functional groups (hydroxyl, epoxy, carbonyl, etc.) exist in typical GO surfaces, resulting in serious electrical losses. Hence, GO must be processed into reduced graphene oxide (rGO) by the removal of most of the oxygen-containing functional groups. This research concentrates on the reduction efficiency of GO films that are manufactured using atmospheric-pressure and continuous plasma irradiation. Before and after sessions of plasma irradiation with various irradiation times, shelters, and working distances, the surface, physical, and electrical characteristics of homemade GO and rGO films are measured and analyzed. Experimental results showed that the sheet resistance values of rGO films with silicon or quartz shelters were markedly lower than those of GO films because the rGO films were mostly deprived of oxygen-containing functional groups. The lowest sheet resistance value and the largest carbon-to-oxygen ratio of typical rGO films were approximately 90 Ω/sq and 1.522, respectively. The intensity of the C–O bond peak in typical rGO films was significantly lower than that in GO films. Moreover, the intensity of the C–C bond peak in typical rGO films was considerably higher than that in GO films.

Fabrication of biodegradable polyurethane electrospun webs of fibers modified with biocompatible graphene oxide nanofiller

2021 ◽  
pp. 152808372110031
Author(s):  
Aleksandra Ivanoska-Dacikj ◽  
Petre Makreski ◽  
Gordana Bogoeva-Gaceva
Keyword(s):  
Graphene Oxide ◽  
Applied Voltage ◽  
Polymer Concentration ◽  
Oxidative Degradation ◽  
Processing Parameters ◽  
Morphological Characterization ◽  
High Dispersion ◽  
Forming Process ◽  
Pumping Rate ◽  
Polyester Urethane

A successful optimization of the electrospinning parameters for obtainment of biodegradable polyester urethane (DP) webs of fibers, neat and graphene oxide (GO) modified, was performed. The effect of the processing parameters (distance between the needle tip and the collector, applied voltage, and flowing rate), solution type and polymer concentration, on the fiber-forming process and the obtained fibers’ morphology was examined. The best homogeneity of the fibers was achieved for 12 wt% DP dissolved in 80:20 wt% mixture of chloroform and ethanol, applying similar processing parameters for the neat and modified samples (0.5 ml/h pumping rate, 15 kV applied voltage, and 150 mm distance to the collector, for the neat sample, and 0.4 ml/h, 18 kV, and 110 mm, for the GO modified samples). The main novelty of this work is the modification of DP with low quantities (0.5, 1.0 and 2.0 wt%) of GO – the “next generation” nanomaterial for stem cell control. The morphological characterization revealed a fibrous microstructure consisting of randomly oriented fibers with a diameters ranging from hundreds nanometers to couple micrometers, representing a feasible imitation of the structure of extracellular matrix (ECM). The XRD studies showed high dispersion of GO in DP matrix and even exfoliation for the sample that contains 2 wt% GO. Raman studies neatly complemented the highest filler/matrix interactions and the superior levels of dispersion for this sample. TGA was used to analyze the thermo-oxidative degradation and also to determine the actual content of GO present in the samples.

LDPE Building Blocks with Controlled Graphene-oxide Interfaces: Composite Manufacturing and Electric Property Investigation

2016 ◽  
Vol 136 (2) ◽  
pp. 93-98 ◽  
Author(s):  
Paolo Mancinelli ◽  
Valentina Santangelo ◽  
Davide Fabiani ◽  
Andrea Saccani ◽  
Maurizio Toselli ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Building Blocks ◽  
Electric Property ◽  
Oxide Interfaces ◽  
Composite Manufacturing

X-Ray Photoelectron Spectroscopy Study on Reduction of Graphene Oxide with Hydrazine Hydrate

2011 ◽  
Vol 287-290 ◽  
pp. 539-543 ◽  
Author(s):  
Wen Shi Ma ◽  
Jun Wen Zhou ◽  
Xiao Dan Lin
Keyword(s):  
Graphene Oxide ◽  
Hydrazine Hydrate ◽  
Photoelectron Spectroscopy ◽  
Reduction Rate ◽  
Reduction Reaction ◽  
Chemical Compositions ◽  
Total Oxygen ◽  
Graphene Oxides ◽  
X Ray ◽  
Oxygen Groups

Graphene oxide was prepared through Hummers' method，then different reduced graphenes were prepared via reduction of graphene oxide with hydrazine hydrate for 1h、12h and 24h. X-ray photoelectron spectroscopy (XPS) was used for the characterization of graphene oxide and the reduced graphenes. The variation of the contents of carbon in carbon and oxygen functional groups and chemical compositions of graphene oxides were investigated through analysis the content of different carbon atoms in different reduced graphenes. The results showed that the reduction reaction was very fast in the first 1 h, the content of total oxygen bonded carbon atoms decreased from 83.6% to 22.1%, and then after the reduction rate became very slow. After 12h, the content of total oxygen bonded carbon atom is 19.56%, only 2.54% lower than that of 1h’s. At the same time, C-N was introduced in the graphene oxides; this increased the stereo-hindrance for hydrazine hydrate attacking the C-Oxygen groups, thus reduced the reduction rate. After reduction for 24h, there still exists 16.4% oxygen bonded carbon atoms and the total conversion ratio of graphene approaches 70%.

Preparation of graphene oxide by dry planetary ball milling process from natural graphite

RSC Advances ◽  
2016 ◽  
Vol 6 (15) ◽  
pp. 12657-12668 ◽  
Author(s):  
Pranita Dash ◽  
Tapan Dash ◽  
Tapan Kumar Rout ◽  
Ashok Kumar Sahu ◽  
Surendra Kumar Biswal ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Ball Milling ◽  
High Energy ◽  
Milling Process ◽  
Graphene Oxides ◽  
Natural Graphite ◽  
Ball Milling Process ◽  
Planetary Ball Milling

Graphene oxides (GO) with different degrees of oxidation have been prepared by an in-house designed horizontal high energy planetary ball milling process.

Well-Aligned Graphene Oxide Nanosheets Decorated with Zinc Oxide Nanocrystals for High Performance Photocatalytic Application

2015 ◽  
Vol 14 (03) ◽  
pp. 1550007 ◽  
Author(s):  
K. Kaviyarasu ◽  
C. Maria Magdalane ◽  
E. Manikandan ◽  
M. Jayachandran ◽  
R. Ladchumananandasivam ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Graphene Oxide ◽  
High Performance ◽  
Chemical Reduction ◽  
Visible Region ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Graphene Oxides ◽  
X Ray ◽  
Nanoscale Structures

Graphene oxide (GO) nanosheets modified with zinc oxide nanocrystals were achieved by a green wet-chemical approach. As-obtained products were characterized by XRD, Raman spectra, XPS, HR-TEM, EDS, PL and Photocatalytic studies. XRD studies indicate that the GO nanosheet have the same crystal structure found in hexagonal form of ZnO . The enhanced Raman spectrum of 2D bands confirmed formation of single layer graphene oxides. The gradual photocatalytic reduction of the GO nanosheet in the GO : ZnO suspension of ethanol was studied by using X-ray photoelectron (XPS) spectroscopy. The nanoscale structures were observed and confirmed using high resolution transmission electron microscopy (HR-TEM). The evolution of the elemental composition, especially the various numbers of layers were determined from energy dispersive X-ray spectra (EDS). PL properties of GO : ZnO nanosheet were found to be dependent on the growth condition and the resultant morphology revealed that GO nanosheet were highly transparent in the visible region. The photocatalytic performance of GO : ZnO nanocomposites was performed under UV irradiation. Therefore, the ZnO nanocrystals in the GO : ZnO composite could be applied in gradual chemical reduction and consequently tuning the electrical conductivity of the graphene oxide nanosheet.

Optical Characteristics of Multilayer Reduced Graphene Oxides Films Fabricated Using UV Oven Spraying Technique with Various Interval Irradiation Time

2021 ◽  
Vol 1028 ◽  
pp. 279-284
Author(s):  
Nur Khanifah ◽  
Diyan Unmu Dzujah ◽  
Vika Marcelina ◽  
Rahmat Hidayat ◽  
Fitrilawati ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Irradiation Time ◽  
Active Material ◽  
Reduction Process ◽  
Optical Characteristics ◽  
Graphene Oxides ◽  
Super Capacitor ◽  
Reduced Graphene ◽  
Vis Spectroscopy ◽  
Coating Method

Reduced graphene oxide (RGO) is promising candidate to be used as an active material of super capacitor electrodes. Graphene oxide (GO) is mostly used as a precursor, therefore it is needed to remove its oxygen containing functional groups. Generally, the RGO films are obtained from Graphene Oxide (GO) films which are then treated using thermal reduction or photo reduction process. We developed a spraying coating method that called as UV oven spraying by combining spraying coating method and photo reduction process. By this deposition method, we can obtain RGO films directly from the GO precursor since deposition and photo reduction steps are taken place at the same time. Level of oxygen removal of the obtained RGO film depends on irradiation intensity and length of irradiation. In this work, we report the effect of varied length of irradiation time on the RGO optical characteristics. We prepared multilayer of RGO films using UV oven spraying technique on quartz substrates from 0.5 mg/ml commercial GO dispersion (Graphenea) with varied the UV irradiation time. We used 125-Watt mercury lamp that was set at distance of 30 cm from substrates. We examined the effect of varied of length of irradiation time on its optical characteristics using UV-Vis Spectroscopy. Level of reduction by provided irradiation time was examined using SEM/EDS measurement.

The effect of large area graphene oxide (LAGO) nanosheets on the mechanical properties of polyvinyl alcohol

2016 ◽  
Vol 36 (4) ◽  
pp. 399-405 ◽  
Author(s):  
Khalid Nawaz ◽  
Muhammad Ayub ◽  
Noaman Ul-Haq ◽  
M.B. Khan ◽  
Muhammad Bilal Khan Niazi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Molecular Level ◽  
Large Area ◽  
Graphene Oxides ◽  
Elongation At Break ◽  
Graphene Oxide Sheets ◽  
Excellent Improvement

Abstract Large area graphene oxide sheets were synthesized, dispersed in water and used as nanofiller for mechanical improvement in terms of Young’s modulus and ultimate tensile strength (UTS) of polyvinyl alcohol (PVA) at low loading. The molecular level dispersion and interfacial interactions between the graphene oxides and polymeric matrix PVA were the real challenges. An excellent improvement in mechanical properties at 0.35 wt% loading was observed. Modulus improved from 1.58 GPa to 2.72 GPa (~71% improvement), UTS improved from 120 MPa to 197 MPa (~65% improvement), and in spite of these improvements, interestingly, there was no fall in elongation at break at this loading.

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