Controlled Functionalization of Graphene by Oxo-addends

2017 ◽  
Vol 2 (3) ◽  
Author(s):  
Siegfried Eigler ◽  
Andreas Hirsch
Keyword(s):  
Graphene Oxide ◽  
Carbon Layer ◽  
Lattice Defects ◽  
Hydroxyl Groups ◽  
Functionalized Graphene ◽  
Chemical Functionalization ◽  
Layer Graphene ◽  
Number Of Layers ◽  
Carbon Framework ◽  
Derivatives Of

AbstractThe single carbon layer graphene and especially its oxidized derivatives, such as graphene oxide (GO), are in the focus of research that started already 150 years ago [1–6]. GO is a collective term for various single layers of graphene (with lattice defects) functionalized by oxo-addends. The type of oxo-groups is not defined, but epoxy and hydroxyl groups dominate the structure in addition to in-plane lattice defects on the percent scale. Those defects are rarely considered in chemical functionalization approaches and it is impossible to distinguish between functionalization of surface oxo-groups and in-plane oxo-groups.This chapter focuses on functionalized derivatives of graphene with an almost intact carbon framework, termed “oxo-functionalized graphene” (oxo-G1, index indicates the number of layers). Avoiding in-plane defects further allows the development of a controlled chemistry of graphene with oxo-addends. However, general approaches of conventional GO chemistry are summarized in a separate section.

scholarly journals Effect of Graphene oxide or Functionalized Graphene Oxide on the Copolymerization Kinetics of Styrene/n-butyl Methacrylate

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 999 ◽  
Author(s):  
Ioannis Tsagkalias ◽  
Afrodite Vlachou ◽  
George Verros ◽  
Dimitris Achilias
Keyword(s):  
Graphene Oxide ◽  
Radical Copolymerization ◽  
Butyl Methacrylate ◽  
Side Reactions ◽  
Hydroxyl Groups ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
Molecular Weights ◽  
Diffusion Controlled ◽  
Kinetic Rate Constants

Nanocomposite materials based on copolymers of styrene and n-butyl methacrylate with either graphene oxide (GO) or functionalized graphene oxide (F-GO) were synthesized using the in-situ bulk radical copolymerization technique. Reaction kinetics was studied both experimentally and theoretically using a detailed kinetic model also taking into account the effect of diffusion-controlled phenomena on the reaction kinetic rate constants. It was found that the presence of GO results in lower polymerization rates accompanied by the synthesis of copolymers having higher average molecular weights. In contrast, the presence of F-GO did not seem to significantly alter the conversion vs time curves, whereas it results in slightly lower average molecular weights. The first observation was attributed to side reactions of the initiator primary radicals with the hydroxyl groups on the surface of GO, resulting in lower initiator efficiency, whereas the second to grafted structures formed from copolymer macromolecules on the F-GO surface. The copolymerization model predictions including MWD data were found to be in satisfactory agreement with the experimental data. At least four adjustable parameters were employed and their best-fit values were provided.

Enhancement of Hydrophobility and Thermal Property of Graphene Oxide by Paratoluidine Chemical Functionalization

2014 ◽  
Vol 809-810 ◽  
pp. 243-247
Author(s):  
Zhi Jia Luo ◽  
Hong Zhang Geng ◽  
Song Ting Zhang ◽  
Bao Tan Du ◽  
Xing Zhang ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Graphene Oxide ◽  
Thermal Property ◽  
Functional Groups ◽  
Drug Delivery Systems ◽  
Graphite Powder ◽  
Hydroxyl Groups ◽  
Chemical Functionalization ◽  
Hummers Method ◽  
Modified Hummers Method

Graphene oxide (GO) is typically synthesized by graphite powder under strong oxidizing reaction, possessing with the same set of functional groups: epoxy and hydroxyl in basal plane and carboxyl and hydroxyl groups existence on the flake edges which endow GO with amphipathy. GO and its functionalized derivatives have been successfully tested in many domains, such as polymer composites, biosensors, drug delivery systems, etc. In this paper, GO was prepared by a modified Hummers method employing improved process (preparation and separation), aiming at industrialization with the lowest cost. Moreover, some novel functional groups with different properties were controlled chemically grafted onto GO to modify the wettability and reaction activity with other materials. The hydrophobicity and the thermal property of graphene oxide were enhanced by chemical functionalization.

scholarly journals The approximation of X-ray diffraction profiles of thermally reduced nanostructured derivatives of graphene oxide

2020 ◽  
pp. 17-26
Author(s):  
Н.С. САЕНКО ◽  
А.М. ЗИАТДИНОВ
Keyword(s):  
Graphene Oxide ◽  
Probability Density Function ◽  
Probability Density ◽  
Polar Angle ◽  
Relative Content ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Number Of Layers ◽  
Derivatives Of

В работе представлен метод моделирования рентгеновских дифрактограмм пленок термически восстановленных наноструктурированных производных оксида графена с помощью линейной комбинации теоретических профилей порошков квазидвумерно-разориентированных несколькослойных турбостратных нанографенов (нанографитов). Метод позволяет определять относительное содержание нанографитов с различными средними размерами и числом слоев, а также функцию плотности вероятности, характеризующую долю частиц в порошке повернутых на заданный полярный угол. Предложенная процедура моделирования пригодна также для аппроксимации экспериментальных рентгенограмм любых материалов, содержащих протяженные квазидвумерно-разориентированные структуры турбостратных нанографитов. The paper outlines the procedure of modeling X-ray diffractogram of films for thermally reduced nanostructured graphene oxide derivatives using a linear combination of the theoretical profiles for powders of quasi-two-dimensional misoriented few-layer turbostratic nanographenes (nanographites). The method allows us to determine the relative content of nanographites with various average sizes and number of layers, as well as a probability density function characterizing the fraction of particles in the powder, which is rotated by a certain polar angle. The proposed modeling procedure is also suitable for the approximation of experimental X-ray diffractograms of any materials containing extended quasi-two-dimensional misoriented structures of turbostratic nanographites.

Synthetic possibility of polystyrene functionalization based on hydroxyl groups of graphene oxide as nucleophiles

2015 ◽  
Vol 39 (7) ◽  
pp. 5096-5099 ◽  
Author(s):  
Rongbing Yu ◽  
Shupeng Zhang ◽  
Yuting Luo ◽  
Ruofei Bai ◽  
Jiangfang Zhou ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Nucleophilic Substitution ◽  
Hydroxyl Groups ◽  
Chemical Functionalization ◽  
Wet Chemical ◽  
Heterogeneous Phase

The successful wet chemical functionalization of graphene oxide with polystyrene offered the possibility of nucleophilic substitution in heterogeneous phase reactions.

scholarly journals Comparison Study on the Adsorption Behavior of Chemically Functionalized Graphene Oxide and Graphene Oxide on Cement

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3274
Author(s):  
Min Wang ◽  
Hao Yao
Keyword(s):  
Graphene Oxide ◽  
Layer Thickness ◽  
Steric Hindrance ◽  
Adsorption Layer ◽  
Adsorption Behavior ◽  
Functionalized Graphene ◽  
Comparison Study ◽  
Chemical Functionalization ◽  
Adsorption Amount ◽  
Branched Chain

Chemical functionalization of graphene oxide (GO) is one kind of advanced strategy to eliminate the negative effects on the flowability of cement with GO. The adsorption behavior of admixture on cement plays a vital role in the flowability of cement-based materials. Herein, the comparison study on the adsorption behavior (including adsorption amount, adsorption kinetics, adsorption isotherms and adsorption layer thickness) of three kinds of chemically functionalized graphene oxides (CFGOs) with different polyether amine branched-chain lengths and GO on cement is reported. The results of CFGOs and GO adsorption data on cement particles were all best fitted with the pseudo-second-order kinetic model, and also conformed to the Freundlich isothermal model, indicating that the adsorption of CFGOs and GO on cement both were multilayer type and took place in a heterogeneous manner. The adsorption of CFGOs and GO on cement was not just physical adsorption, but also engaged chemical adsorption. In contrast to GO, the adsorption behavior of CFGOs on cement represented a lesser adsorption amount, weaker adsorption capacity and thinner adsorption layer thickness. Moreover, the longer the branched-chain length of CFGOs, the greater the decreasing degrees of adsorption amount, adsorption capacity and adsorption layer thickness. Due to the consumption of the carboxyl group (-COOH) by chemical functionalization, the anchoring effect of CFGOs was weaker than GO, and the steric hindrance effect generated from branched-chains which weakened the van der Waals forces among CFGOs layers. Moreover, the steric hindrance effect strengthened with the increasing branched-chain length, thus preventing the cement particles from aggregation, which resulted in satisfactory flowability of CFGOs with incorporation of cement rather than GO.

scholarly journals Multisulfonate hyperbranched polyglycerol functionalized graphene oxide as an efficient reusable catalyst for green synthesis of benzo[a]pyrano-[2,3-c]phenazines under solvent-free conditions

RSC Advances ◽  
2019 ◽  
Vol 9 (13) ◽  
pp. 7400-7410 ◽  
Author(s):  
Hossein Naeimi ◽  
Maryam Farahnak Zarabi
Keyword(s):  
Graphene Oxide ◽  
Green Synthesis ◽  
Acid Catalyst ◽  
Solvent Free ◽  
Reusable Catalyst ◽  
Hydroxyl Groups ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
Solvent Free Conditions ◽  
Hyperbranched Polyglycerol

A novel acid catalyst was prepared based on growing hyperbranched polyglycerol (HPG) on the surface of graphene oxide. Then, the hydroxyl groups of HPG on graphene oxide were functionalized by sulfonate groups to form an acid catalyst.

Fabrication of layer-by-layer graphene oxide thin film on copper substrate by electrophoretic deposition

2020 ◽  
Vol 59 (12) ◽  
pp. 125001
Author(s):  
Nan Ye ◽  
Satoka Ohnishi ◽  
Mitsuhiro Okada ◽  
Kazuto Hatakeyama ◽  
Kazuhiko Seki ◽  
...  
Keyword(s):  
Thin Film ◽  
Graphene Oxide ◽  
Electrophoretic Deposition ◽  
Copper Substrate ◽  
Oxide Thin Film ◽  
Layer By Layer ◽  
Layer Graphene

Polymer Functionalized Graphene Oxide: A Versatile Nanoplatform for Drug/Gene Delivery

2015 ◽  
Vol 19 (18) ◽  
pp. 1828-1837 ◽  
Author(s):  
George V. Theodosopoulos ◽  
Panayiotis Bilalis ◽  
Georgios Sakellariou
Keyword(s):  
Graphene Oxide ◽  
Gene Delivery ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide

The role of secondary alcoholic groups of D-galacturonan in its degradation with exo-D-galacturonanase

1980 ◽  
Vol 45 (2) ◽  
pp. 427-434 ◽  
Author(s):  
Kveta Heinrichová ◽  
Rudolf Kohn
Keyword(s):  
Acetyl Derivative ◽  
Competitive Inhibitor ◽  
Hydroxyl Groups ◽  
Pectic Acid ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
The Individual ◽  
Degradation Degree ◽  
Derivatives Of

The effect of exo-D-galacturonanase from carrot on O-acetyl derivatives of pectic acid of variousacetylation degree was studied. Substitution of hydroxyl groups at C(2) and C(3) of D-galactopyranuronic acid units influences the initial rate of degradation, degree of degradation and its maximum rate, the differences being found also in the time of limit degradations of the individual O-acetyl derivatives. Value of the apparent Michaelis constant increases with increase of substitution and value of Vmax changes. O-Acetyl derivatives act as a competitive inhibitor of degradation of D-galacturonan. The extent of the inhibition effect depends on the degree of substitution. The only product of enzymic reaction is D-galactopyranuronic acid, what indicates that no degradation of the terminal substituted unit of O-acetyl derivative of pectic acid takes place. Substitution of hydroxyl groups influences the affinity of the enzyme towards the modified substrate. The results let us presume that hydroxyl groups at C(2) and C(3) of galacturonic unit of pectic acid are essential for formation of the enzyme-substrate complex.

NiAg-graphene quantum dot-graphene hybrid with high oxidase-like catalytic activity for sensitive colorimetric detection of malathion

2021 ◽  
Author(s):  
Xu Dan ◽  
Ruiyi Li ◽  
Qinsheng Wang ◽  
Yongqiang Yang ◽  
Haiyan Zhu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Catalytic Activity ◽  
Quantum Dot ◽  
Colorimetric Detection ◽  
Graphene Quantum Dots ◽  
Functionalized Graphene ◽  
Graphene Quantum Dot ◽  
Nickel Silver

The paper reports the synthesis of nickel-silver-graphene quantum dot-graphene hybrid. Histidine-functionalized graphene quantum dots (His-GQDs) were bonded to graphene oxide (GO) and then combined with Ni2+ and Ag+ to form...

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