Chemical Modification Of Graphene Oxide Research Articles

Enhanced antibacterial effect of polypyrazole-graphene oxide composite

Besides excellent physical performances, graphene oxide (GO) has been widely acknowledged as a potential antibacterial material. Chemical modification of GO was taken out with polypyrazole by facile amidation in the presence of dicyclohexylcarbodiimide (DCC) and then generated polypyrazole-graphene oxide (FGO) nanohybrid. FGO nanohybrid showed smooth and multilayer structures by scanning electron microscopy. The value of static water contact angle of FGO is 103°, suggesting FGO was a hydrophobic material. Thermo gravimetric analysis of FGO showed a 65% mass loss up 50 to 600 °C, suggesting that FGO is a thermal stability material. Inactivation efficiency test of nominal Escherichia coli cells showed that the viability greatly decreased to 7% after 4 h incubation with FGO under 37 °C, indicating an outstanding antibacterial ability of FGO much better than that of polypyrazole and GO.

Electrochemical detection of uric acid via uricase-immobilized graphene oxide

Measurement of the uric acid level in the body can be improved by biosensing with respect to the accuracy, sensitivity and time consumption. This study has reported the immobilization of uricase onto graphene oxide (GO) and its function for electrochemical detection of uric acid. Through chemical modification of GO using 1-ethyl-3-(dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysulfosuccinimide (NHS) as cross-linking reagents, the enzyme activity of the immobilized uricase was much comparable to the free enzyme with 88% of the activity retained. The modified GO-uricase (GOU) was then subjected to electrocatalytic detection of uric acid (UA) via cyclic voltammetry (CV). For that reason, a glassy carbon electrode (GCE) was modified by adhering the GO along with the immobilized uricase to facilitate the redox reaction between the enzyme and the substrate. The modified GOU/GCE outperformed a bare electrode through the electrocatalytic activity with an amplified electrical signal for the detection of UA. The electrocatalytic response showed a linear dependence on the UA concentration ranging from 0.02 to 0.49 mM with a detection limit of 3.45 μM at 3σ/m. The resulting biosensor also exhibited a high selectivity towards UA in the presence of other interference as well as good reproducibility.

A Novel Nanodrag Reducer for Low Permeability Reservoir Water Flooding: Long-Chain Alkylamines Modified Graphene Oxide

Chemical modification of graphene oxide (GO) by grafting hydrophobic chains on the surface has drawn much attention nowadays in the academic world, and it was suggested that modified GO could lead to new functionalized materials with specific structure and different properties. In this paper, modified GO (M-GO) were synthesized by chemically grafting alkylamines with varying chain lengths on the graphene oxide surface. Successful grafting of alkylamines was confirmed using Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and Raman spectroscopy measurements. In addition, we investigated the properties of M-GO as nanodrag reducer in low permeability reservoir water flooding. Water contact angle (CA) measurements revealed that the hydrophobic nature of GO depended on the chain length of the grafted alkylamines. And flooding experiments showed that the hexadecylamine- and octadecylamine-modified GO had an ability to reduce water injection pressure and improve water-phase permeability of the low permeability reservoirs during water flooding. So the M-GO would have potential applications in oilfield exploitation.

Recent Advances in Laser Utilization in the Chemical Modification of Graphene Oxide and Its Applications

A dramatic rise in research interest in laser‐induced graphene oxide (GO) reduction and modification requires an overview of the most recent works on this subject. Typical methods for the recognition and confirmation of modified graphene and its derivatives, such as Raman, Fourier‐transform infra‐red (FTIR), X‐ray photoelectron (XP), and ultraviolet‐visible (UV–vis) spectroscopies, are introduced briefly in this review. A major part of the survey is devoted to the main modification ways and the laser parameters used in the literature. A discussion of possible reduction and modification mechanisms is also presented. Recent applications, especially in the biomedical field such as cell therapy treatment, as well as significant results of GO modification, are discussed in detail. Finally, perspectives for the application of laser‐induced GO modifications in passive THz photonics and biomedicine are briefly addressed.

Chemical Modification of Graphene Oxide through Diazonium Chemistry and Its Influence on the Structure-Property Relationships of Graphene Oxide-Iron Oxide Nanocomposites.

4-Carboxyphenyl groups are covalently grafted onto graphene oxide via diazonium chemistry for studying their role on the adsorption of iron oxide nanoparticles. The nanoparticles are deposited via a novel phase-transfer approach involving specific interactions at the interface between two immiscible solvents. The increased density and the homogeneous distribution of surface carboxyl moieties enable the preparation of a nanocomposite with improved iron oxide distribution and loading. Structure-properties relationships are investigated by analysing the electrochemical properties of the nanocomposites, which are regarded as promising active materials for application in supercapacitors. It is demonstrated that the nature of the interactions between the components similarly affects the overall electrochemical performances of the nanocomposites and the structure of the materials.

Functional graphene by thiol-ene click chemistry.

Thiol‐ene click reaction was successfully employed for chemical modification of graphene oxide (GO) by one‐step synthesis. Herein, 2,2‐azobis(2‐methylpropionitrile) (AIBN) was used as thermal catalyst and cysteamine hydrochloride (HS−(CH2)2−NH2HCl) was used as thiol‐containing compound, which is incorporated to GO surface upon reaction with the C=C bonds. The hydrochloride acts as protecting group for the amine, which is finally eliminated by adding sodium hydroxide. The modified GO contains both S‐ and N‐containing groups (NS‐GO). We found that NS‐GO sheets form good dispersion in water, ethanol, and ethylene glycol. These graphene dispersions can be processed into functionalized graphene film. Besides, it was demonstrated that NS‐GO was proved to be an excellent host matrix for platinum nanoparticles. The developed method paves a new way for graphene modification and its functional nanocomposites.

Advances in Synthesis and Properties of Poly(<i>ε-</i>caprolactone)/Carbon Nanocomposites

Recently, Graphene oxide (GO), carbon nanotubes (CNTs) and fullerenes (C60) have attracted enormous interests because of their extraordinary properties, and they can improve various kinds of properties of polymeric materials. The latest achievements on investigating applications and properties including mechanical properties, thermal properties, crystallization behavior and bioactivity of poly (ε-caprolactone). (PCL)/GO, PCL/CNTs and PCL/ C60nanocomposites obtained in the last five years were summarized in this paper. The relationships between the properties of nanocomposites and the loading, dispersion chemical modification of GO, CNTs and C60were also discussed.

Chemical modification of graphene oxide with carbethoxycarbene under microwave irradiation

The structure of graphene oxide (GO) enables it to act as the olefin in cyclopropanation reaction with ethyl diazoacetate (EDA) under microwave irradiation. This versatile synthetic method offers a powerful method for the rapid chemical modification of GO. The attachment of carbethoxycarbene (CEC) to GO was confirmed by the results of FTIR, XPS, Raman, and UV–vis analysis.

Ultrathin SnS2 Nanoparticles on Graphene Nanosheets: Synthesis, Characterization, and Li-Ion Storage Applications

Ultrathin SnS2 nanoparticle decorated graphene nanosheet (GNS) electrode materials with delaminated structure were prepared using stepwise chemical modification of graphene oxide (GO) nanosheets at very dilute conditions, followed by a hydrothermal treatment. The chemical modification of the graphene nanosheet surface with Sn ions enables the precipitation of ultrathin nanoparticles. The TEM analysis reveals the SnS2 nanoparticles are homogeneously distributed on the loosely packed graphene surface in such a way that the GNS restacking was hindered. X-ray photoelectron spectroscopic analysis reveals the bonding characteristics of the SnS2 on the GNS. The obtained nanocomposite exhibits a reversible capacity of 1002 mAh/g, which is significantly higher than its calculated theoretical capacity (584 mAh/g). Furthermore, its cycling performance is enhanced and after 50 cycles, and the charge capacity still remained 577 mAh/g, which is very close to its theoretical capacity. Due to the synergic effect, the Li-...

DNA Origami Nanopatterning on Chemically Modified Graphene

Nanoscale folding of DNA: Taking advantage of facile solution processing, pattern formation under light irradiation, and ready chemical modification of graphene oxide, various patterned films of chemically modified graphene were prepared and employed for spatial patterning of DNA origami structures (see picture). The patterning of DNA origami structures required highly selective adsorption on graphene oxide surfaces.