Deep research about the mechanisms of graphene oxide (GO) aggregation in alkaline cement pore solution

Zhao, Li; Zhu, Shuaishuai; Hao, W.; Zhang, Xingchi; Tao, Qingqing; Song, Luguang; Song, Yulong; Guo, Xinli

doi:10.1016/j.conbuildmat.2020.118446

Cited by 60 publications

(17 citation statements)

References 41 publications

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“…Interestingly, the contribution of the surface atomic composition of sp 2 CC species to the C 1s core level decreased from 78.91% to 77.21%, 77.15%, and 76.64% as the deposition time increased from 5 to 10, 15, and 20 min. This demonstrates a definite influence of the thickness of the G mesolayer on its chemical properties, in this case exhibited by the presumed G deoxygenation effects. , Namely, the reduction in the atomic proportion of CC bonds occurs at the cost of increasing the proportion of CO bonds, involving the oxygen atoms from the G layer.…”

Section: Resultsmentioning

confidence: 80%

“…This demonstrates a definite influence of the thickness of the G mesolayer on its chemical properties, in this case exhibited by the presumed G deoxygenation effects. 50,51 Namely, the reduction in the atomic proportion of CC bonds occurs at the cost of increasing the proportion of CO bonds, involving the oxygen atoms from the G layer. with the deposition time.…”

Section: Resultsmentioning

confidence: 99%

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Taking Hydroxyapatite-Coated Titanium Implants Two Steps Forward: Surface Modification Using Graphene Mesolayers and a Hydroxyapatite-Reinforced Polymeric Scaffold

Fathi

Ahmed

Afifi

et al. 2020

ACS Biomater. Sci. Eng.

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Coating with hydroxyapatite (HAP) presents a mainstream strategy for rendering bioinert titanium implants bioactive. However, the low porosity of pure HAP coatings does not allow for the infiltration of the surface of the metallic implant with the host cells. Polymeric scaffolds do enable this osseointegration effect, but their bonding onto titanium presents a challenge because of the disparity in hydrophilicity. Here, we demonstrate the inability of a composite scaffold composed of carbonated HAP (CHAP) nanoparticles interspersed within electrospun ε-polycaprolactone (PCL) nanofibers to bind onto titanium. To solve this challenge, an intermediate layer of graphene nanosheets was deposited in a pulsed laser deposition process, which facilitated the bonding of the scaffold. The duration of the deposition of graphene (0, 5, 10, 15, and 20 min) and the thickness of its mesolayer affected numerous physical and chemical properties of the material, including the surface atomic proportion of carbon bonds, the orientation and interlinking of the polymeric nanofibers, and the surface roughness, which increased in direct proportion with the thickness of the graphene mesolayer. Because the polymeric scaffold did not adhere onto the surface of pure titanium, no cells were detected growing on it in vitro. In contrast, human fibroblasts adhered, spread, and proliferated well on all the substrates sputtered with both graphene and the composite scaffold. The orientations of cytoskeletal filopodia and lamellipodia were largely determined by the topographic orientation of the nanofibers and the geometry of the surface pores, attesting to the important effects that the presence of a scaffold has on the cellular behavior. The protection of titanium from corrosion in the simulated body fluid (SBF) was enhanced by coating with graphene and the composite scaffold, with the most superior resistance to the attack of the corrosive ions being exhibited by the substrate subjected to the shortest duration of the graphene deposition because of the highest atomic ratio of C–C to C–O bonds detected in it. Overall, some properties of titanium, such as roughness and wettability, were improved monotonously with an increase in the thickness of the graphene mesolayer, while others, such as cell viability and resistance to corrosion, required optimization, given that they were diminished at higher graphene mesolayer thicknesses. Nevertheless, every physical and chemical property of titanium analyzed was significantly improved by coating with graphene and the composite scaffold. This type of multilayer design evidently holds a great promise in the design of biomaterials for implants in orthopedics and tissue engineering.

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Section: Resultsmentioning

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Taking Hydroxyapatite-Coated Titanium Implants Two Steps Forward: Surface Modification Using Graphene Mesolayers and a Hydroxyapatite-Reinforced Polymeric Scaffold

Fathi

Ahmed

Afifi

et al. 2020

ACS Biomater. Sci. Eng.

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“…However, dispersion of FMWCNTs in aqueous solution is highly challenging due to van der Waals forces between the materials. At concentrations between .003% and .012%, FMWCNTs tend to cause agglomeration, which reduces mechanical properties can be observed in Figure 13 48 …”

Section: Resultsmentioning

confidence: 99%

“…At concentrations between .003% and .012%, FMWCNTs tend to cause agglomeration, which reduces mechanical properties can be observed in Figure 13. 48…”

Section: 42mentioning

confidence: 99%

Comparative study of physico‐mechanical performance of PPC mortar incorporated 1D/2D functionalized nanomaterials

Bhatrola

Kothiyal

2023

Int J Applied Ceramic Tech

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The current study investigates the effect of adding graphene oxide (GO) and functionalized multiwalled carbon nanotubes (FMWCNTs) in pozzolana Portland cement (PPC) mortars to evaluate their mechanical and electrical resistivity properties. The effects of 1D and 2D functionalized carbon nanomaterials in PPC have been studied. At 90 days of curing, the g1PPC (.0015% of GO by weight percentage of binder) and c1PPC (.0015% of FMWCNTs by weight percentage of binder) showed a significant improvement in the physico-mechanical performance of the pozzolana Portland cement composited (PPCC) mortars. The enhanced compressive strength was found to be 11.67% and 8.74% for g1PPC and c1PPC, respectively, as compared to the control specimen (PPC-C). The increased tensile splitting strength was observed to be 26.39% and 20.61% for g1PPC and c1PPC, respectively, as compared to PPC-C. The electrical resistivity of PPCC mortars have been shown a significant improvement for g1PPC and c1PPC. This might be due to the densification of calcium silicate hydrate (C-S-H) gel and hydration products. Powdered X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR). Field emission-scanning electron microscope (FE-SEM) was able to support the improved strength of PPCC mortars via formation of ettringite and needle-shaped crystals in hydrated products.

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“…Compared with other nanomaterials, owing to the oxygen-containing functional groups on the surface of GO, − the van der Waals force between GO sheets is significantly weakened and the electrostatic repulsion between GO sheets is increased, resulting in better dispersion of GO. , However, in the strong alkaline environment formed by cement hydration, metal cations such as Ca 2+ , K + , and Na + have a significant influence on the dispersibility of GO. , Among these, K + and Na + can reduce the dispersion stability of GO by hindering the ionization of GO oxygen-containing functional groups and weakening the electrostatic repulsion between layers. As shown in Figure , Ca 2+ not only weakens the electrostatic repulsion between GO layers but also reacts with oxygen-containing functional groups (−COOH) on the surface of GO to build a −COO–Ca–OOC– bridge between GO layers, making the edge of GO-formed GO cross-linking clusters, resulting in severe agglomeration of GO.…”

Section: Dispersive Properties Of Gomentioning

confidence: 99%

Catalysis and Regulation of Graphene Oxide on Hydration Properties and Microstructure of Cement-Based Materials

Chen

Xue

et al. 2023

ACS Sustainable Chem. Eng.

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Graphene oxide (GO) is a two-dimensional material that adds functionalized oxygen-containing groups on the surface of graphene through strong acid oxidation. The oxygen-containing functional groups on the surface make GO have good dispersion and surface activity. When GO is incorporated into cement-based materials, while providing nucleation sites for cement hydration, it can also react with ions released by cement hydration. Therefore, GO has a catalytic effect on the hydration process of cement and plays a role in regulating the morphology of the hydration products, which in turn affects the formation of the microstructure of cementbased materials. In this study, the catalytic and regulatory effects of GO on the hydration characteristics, pore structure, and internal interface of cement-based materials are reviewed. The analysis shows that the oxygen-containing functional groups on the surface of GO can absorb a large number of water molecules, promote the dissolution of cement particles in water, and adsorb the Ca 2+ released by cement particles, thereby reducing the concentration of Ca 2+ around the cement particles and shortening the induction period of cement hydration. In addition, GO can provide more nucleation sites for cement hydration and shorten the hydration acceleration period. GO promotes the formation of hydration products through the nucleation effect and gradually transforms needle-like and rod-like hydration products into flower-like or polyhedral-like crystals. In addition, GO optimizes the pore structure of cement-based materials when it affects cement hydration and the morphology of hydration products through the above-mentioned effects. In addition, it makes the connection between hydration products closer through the bridging effect, so that the total porosity of cement-based materials decreases, gel-pore content increases, capillary-pore content decreases, and pore structure is significantly optimized. Finally, while optimizing the pore structure of cement-based materials, GO has an obvious optimization effect on the interface transition zone (ITZ) of cement-based materials, which significantly reduces the ITZ width and increases the ITZ density.

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Deep research about the mechanisms of graphene oxide (GO) aggregation in alkaline cement pore solution

Cited by 60 publications

References 41 publications

Taking Hydroxyapatite-Coated Titanium Implants Two Steps Forward: Surface Modification Using Graphene Mesolayers and a Hydroxyapatite-Reinforced Polymeric Scaffold

Taking Hydroxyapatite-Coated Titanium Implants Two Steps Forward: Surface Modification Using Graphene Mesolayers and a Hydroxyapatite-Reinforced Polymeric Scaffold

Comparative study of physico‐mechanical performance of PPC mortar incorporated 1D/2D functionalized nanomaterials

Catalysis and Regulation of Graphene Oxide on Hydration Properties and Microstructure of Cement-Based Materials

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