Reduced and Surface‐Modified Graphene Oxide with Nonlinear Resistivity

Polymeric nanocomposites have been fabricated via in situ cationic polymerization of linseed oil in the presence of surface-modified graphene oxide (SGO).

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Surface modified graphene oxide nanosheets by gold ion implantation as a substrate for surface enhanced Raman scattering

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2017.02.020 ◽

2017 ◽

Vol 703 ◽

pp. 500-507 ◽

Cited By ~ 16

Author(s):

Ashish Pandey ◽

Anjum Qureshi

Keyword(s):

Graphene Oxide ◽

Raman Scattering ◽

Graphene Oxide Nanosheets ◽

Modified Graphene Oxide ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

Enhanced Raman Scattering ◽

Surface Modified ◽

Modified Graphene ◽

Gold Ion

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Characterization of Reduced and Surface-Modified Graphene Oxide in Poly(Ethylene-co-Butyl Acrylate) Composites for Electrical Applications

Polymers ◽

10.3390/polym11040740 ◽

2019 ◽

Vol 11 (4) ◽

pp. 740 ◽

Cited By ~ 5

Author(s):

Carmen Cobo Sánchez ◽

Martin Wåhlander ◽

Mattias Karlsson ◽

Diana C. Marin Quintero ◽

Henrik Hillborg ◽

...

Keyword(s):

Graphene Oxide ◽

Butyl Acrylate ◽

Particle Dispersion ◽

Butyl Methacrylate ◽

High Voltage Direct Current ◽

Modified Graphene Oxide ◽

Filler Fraction ◽

Poly Ethylene ◽

Surface Modified ◽

Modified Graphene

Promising electrical field grading materials (FGMs) for high-voltage direct-current (HVDC) applications have been designed by dispersing reduced graphene oxide (rGO) grafted with relatively short chains of poly (n-butyl methacrylate) (PBMA) in a poly(ethylene-co-butyl acrylate) (EBA) matrix. All rGO-PBMA composites with a filler fraction above 3 vol.% exhibited a distinct non-linear resistivity with increasing electric field; and it was confirmed that the resistivity could be tailored by changing the PBMA graft length or the rGO filler fraction. A combined image analysis- and Monte-Carlo simulation strategy revealed that the addition of PBMA grafts improved the enthalpic solubility of rGO in EBA; resulting in improved particle dispersion and more controlled flake-to-flake distances. The addition of rGO and rGO-PBMAs increased the modulus of the materials up to 200% and the strain did not vary significantly as compared to that of the reference matrix for the rGO-PBMA-2 vol.% composites; indicating that the interphase between the rGO and EBA was subsequently improved. The new composites have comparable electrical properties as today’s commercial FGMs; but are lighter and less brittle due to a lower filler fraction of semi-conductive particles (3 vol.% instead of 30–40 vol.%).

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Organic Functionalized Graphene Oxide Behavior in Water

Nanomaterials ◽

10.3390/nano10061228 ◽

2020 ◽

Vol 10 (6) ◽

pp. 1228

Author(s):

Changwoo Kim ◽

Junseok Lee ◽

Will Wang ◽

John Fortner

Keyword(s):

Graphene Oxide ◽

Divalent Cations ◽

Critical Role ◽

Functionalized Graphene Oxide ◽

Organic Functionalization ◽

Chemical Structures ◽

Modified Graphene Oxide ◽

Surface Modified ◽

Modified Graphene ◽

Hydrophilic Coatings

Surface modified graphene oxide (GO) has received broad interest as a potential platform material for sensors, membranes, and sorbents, among other environmental applications. However, compared to parent (unmodified) GO, there is a dearth of information regarding the behavior of subsequently (secondary) modified GO, other than bulk natural organic matter (NOM) coating(s). Here, we systematically explore the critical role of organic functionalization with respect to GO stability in water. Specifically, we synthesized a matrix of GO-based materials considering a carefully chosen range of bound organic molecules (hydrophobic coatings: propylamine, tert-octylamine, and 1-adamantylamine; hydrophilic coatings: 3-amino-1-propanol and 3-amino-1-adamantanol), so that chemical structures and functional groups could be directly compared. GO (without organic functionalization) with varying oxidation extent(s) was also included for comparison. The material matrix was evaluated for aqueous stability by comparing critical coagulation concentration (CCC) as a function of varied ionic strength and type (NaCl, CaCl2, MgCl2, and MgSO4) at pH 7.0. Without surface derivatization (i.e., pristine GO), increased stability was observed with an increase in the GO oxidation state, which is supported by plate–plate Derjaguin, Landau, Verwey and Overbeek (DLVO) energy interaction analyses. For derivatized GO, we observed that hydrophilic additions (phi-GO) are relatively more stable than hydrophobic organic coated GO (pho-GO). We further explored this by altering a single OH group in the adamantane-x structure (3-amino-1-adamantanol vs. 1-adamantylamine). As expected, Ca2+ and monovalent co-ions play an important role in the aggregation of highly oxidized GO (HGO) and phi-GO, while the effects of divalent cations and co-ions were less significant for pho-GO. Taken together, this work provides new insight into the intricate dynamics of GO-based material stability in water as it relates to surface functionalization (surface energies) and ionic conditions including type of co- and counter-ion, valence, and concentration.

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