Nanomaterials

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15 pages, 3190 KiB

Open AccessArticle

Mechanical Properties and Microstructure of High-Strength Lightweight Concrete Incorporating Graphene Oxide

by Xiaojiang Hong, Jin Chai Lee and Bo Qian

Nanomaterials 2022, 12(5), 833; https://doi.org/10.3390/nano12050833 - 1 Mar 2022

Cited by 25 | Viewed by 3273

Abstract

The increasing demand for high-strength lightweight concrete (HSLWC) with excellent mechanical properties has inspired the development of nanomaterials in fundamentally solving brittleness and cracking. This work investigated the effects of graphene oxide (GO) on the mechanical properties and microstructure of HSLWC, including the [...] Read more.

The increasing demand for high-strength lightweight concrete (HSLWC) with excellent mechanical properties has inspired the development of nanomaterials in fundamentally solving brittleness and cracking. This work investigated the effects of graphene oxide (GO) on the mechanical properties and microstructure of HSLWC, including the workability, density, compressive strength in different curing regimes, splitting tensile strength, flexural strength, modulus of elasticity and scanning electron microscopy (SEM). Six groups of mixtures were mixed with GO aqueous solution at a dosage of 0.00%, 0.02%, 0.04%, 0.05%, 0.06%, and 0.08% by weight of cement, respectively, and dispersed by ultrasound for 30 min. The test results showed that adding a low volume of GO to the specimens could slightly increase the density, rationally reduce the slump, and significantly improve the mechanical properties. The maximum increase in compressive strength, splitting tensile strength, modulus of elasticity and flexural strength of HSLWC with GO at 28 days was by 24%, 17%, 15%, 20%, respectively, as compared with HSLWC without GO. Simultaneously, the SEM results showed that GO could not only fill nano-scale pores, but also regulate the formation and growth of flower-like crystals, which was an important factor for the further improvement of properties. The research results provided a potential new pathway to improve the mechanical properties of HSLWC. Full article

(This article belongs to the Special Issue Investigation and Development of Graphene Oxide-Based Materials)

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10 pages, 4194 KiB

Open AccessArticle

Controllability of Graphene Oxide Doxorubicin Loading Capacity Based on Density Functional Theory

by Jiaming Song, Naiyu Cui, Shixun Sun, Xinyue Lu, Yuxuan Wang, Haoyu Shi, Eui-Seok Lee and Heng-Bo Jiang

Nanomaterials 2022, 12(3), 479; https://doi.org/10.3390/nano12030479 - 29 Jan 2022

Cited by 9 | Viewed by 2901

Abstract

Graphene can be used as a drug carrier of doxorubicin (DOX) to reduce the side effects of doxorubicin. However, there is limited research on the surface chemical modifications and biological effects of graphene oxide (GO). Therefore, it is necessary to explore the DOX [...] Read more.

Graphene can be used as a drug carrier of doxorubicin (DOX) to reduce the side effects of doxorubicin. However, there is limited research on the surface chemical modifications and biological effects of graphene oxide (GO). Therefore, it is necessary to explore the DOX affinity of different oxygen-containing functional groups in the graphene system. We constructed graphene system models and studied the structure and distribution of epoxy and hydroxyl groups on the carbon surface. Based on molecular dynamics simulations and density functional theory (DFT), we investigated the interaction between DOX and either pristine graphene or GO with different ratios of oxygen-containing groups. The hydroxyl groups exhibited a stronger affinity for DOX than the epoxy groups. Therefore, the DOX loading capacity of graphene systems can be adjusted by increasing the ratio of hydroxyl to epoxy groups on the carbon surface. Full article

(This article belongs to the Special Issue Investigation and Development of Graphene Oxide-Based Materials)

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17 pages, 2744 KiB

Open AccessArticle

Tuning the Reduction of Graphene Oxide Nanoflakes Differently Affects Neuronal Networks in the Zebrafish

by Giuseppe Di Mauro, Rossana Rauti, Raffaele Casani, George Chimowa, Anne Marie Galibert, Emmanuel Flahaut, Giada Cellot and Laura Ballerini

Nanomaterials 2021, 11(9), 2161; https://doi.org/10.3390/nano11092161 - 24 Aug 2021

Cited by 12 | Viewed by 3040

Abstract

The increasing engineering of biomedical devices and the design of drug-delivery platforms enriched by graphene-based components demand careful investigations of the impact of graphene-related materials (GRMs) on the nervous system. In addition, the enhanced diffusion of GRM-based products and technologies that might favor [...] Read more.

The increasing engineering of biomedical devices and the design of drug-delivery platforms enriched by graphene-based components demand careful investigations of the impact of graphene-related materials (GRMs) on the nervous system. In addition, the enhanced diffusion of GRM-based products and technologies that might favor the dispersion in the environment of GRMs nanoparticles urgently requires the potential neurotoxicity of these compounds to be addressed. One of the challenges in providing definite evidence supporting the harmful or safe use of GRMs is addressing the variety of this family of materials, with GRMs differing for size and chemistry. Such a diversity impairs reaching a unique and predictive picture of the effects of GRMs on the nervous system. Here, by exploiting the thermal reduction of graphene oxide nanoflakes (GO) to generate materials with different oxygen/carbon ratios, we used a high-throughput analysis of early-stage zebrafish locomotor behavior to investigate if modifications of a specific GRM chemical property influenced how these nanomaterials affect vertebrate sensory-motor neurophysiology—exposing zebrafish to GO downregulated their swimming performance. Conversely, reduced GO (rGO) treatments boosted locomotor activity. We concluded that the tuning of single GRM chemical properties is sufficient to produce differential effects on nervous system physiology, likely interfering with different signaling pathways. Full article

(This article belongs to the Special Issue Investigation and Development of Graphene Oxide-Based Materials)

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11 pages, 4513 KiB

Open AccessArticle

Micro Scalable Graphene Oxide Productions Using Controlled Parameters in Bench Reactor

by Carolina S. Andrade, Anna Paula S. Godoy, Marcos Antonio Gimenes Benega, Ricardo J. E. Andrade, Rafael Cardoso Andrade, Wellington Marcos Silva, Josué Marciano de Oliveira Cremonezzi, Waldemar Augusto de Almeida Macedo, Pedro Lana Gastelois, Helio Ribeiro and Jaime Taha-Tijerina

Nanomaterials 2021, 11(8), 1975; https://doi.org/10.3390/nano11081975 - 31 Jul 2021

Cited by 9 | Viewed by 2800

Abstract

The detailed study of graphene oxide (GO) synthesis by changing the graphite/oxidizing reagents mass ratios (mG/mROxi), provided GO nanosheets production with good yield, structural quality, and process savings. Three initial samples containing different amounts of graphite (3.0 g, 4.5 g, and 6.0 g) [...] Read more.

The detailed study of graphene oxide (GO) synthesis by changing the graphite/oxidizing reagents mass ratios (mG/mROxi), provided GO nanosheets production with good yield, structural quality, and process savings. Three initial samples containing different amounts of graphite (3.0 g, 4.5 g, and 6.0 g) were produced using a bench reactor under strictly controlled conditions to guarantee the process reproducibility. The produced samples were analyzed by Raman spectroscopy, atomic force microscopy (AFM), x-ray diffraction (XDR), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR) and thermogravimetry (TGA) techniques. The results showed that the major GO product comprised of nanosheets containing between 1–5 layers, with lateral size up to 1.8 µm. Therefore, it was possible to produce different batches of graphene oxide with desirable physicochemical characteristics, keeping the amount of oxidizing reagent unchanged. The use of different proportions (mG/mROxi) is an important strategy that provides to produce GO nanostructures with high structural quality and scale-up, which can be well adapted in medium-sized bench reactor. Full article

(This article belongs to the Special Issue Investigation and Development of Graphene Oxide-Based Materials)

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17 pages, 1940 KiB

Open AccessArticle

A Multifactorial Approach to Untangle Graphene Oxide (GO) Nanosheets Effects on Plants: Plant Growth-Promoting Bacteria Inoculation, Bacterial Survival, and Drought

by Tiago Lopes, Catarina Cruz, Paulo Cardoso, Ricardo Pinto, Paula A. A. P. Marques and Etelvina Figueira

Nanomaterials 2021, 11(3), 771; https://doi.org/10.3390/nano11030771 - 18 Mar 2021

Cited by 13 | Viewed by 3118

Abstract

Drought is a limiting factor for agricultural productivity. Climate change threatens to expand the areas of the globe subjected to drought, as well as to increase the severity and duration of water shortage. Plant growth-promoting bacteria (PGPB) are widely studied and applied as [...] Read more.

Drought is a limiting factor for agricultural productivity. Climate change threatens to expand the areas of the globe subjected to drought, as well as to increase the severity and duration of water shortage. Plant growth-promoting bacteria (PGPB) are widely studied and applied as biostimulants to increase plant production and to enhance tolerance to abiotic and biotic constraints. Besides PGPB, studies on the potential of nanoparticles to be used as biostimulants are also thriving. However, many studies report toxicity of tested nanoparticles in bacteria and plants in laboratory conditions, but few studies have reported effects of nanoparticles towards bacterial cells and communities in the soil. The combined application of nanoparticles and PGPB as biostimulant formulations are poorly explored and it is important to unravel the potentialities of their combined application as a way to potentiate food production. In this study, Rhizobium sp. E20-8 and graphene oxide (GO) nanosheets were applied on container-grown maize seedlings in watered and drought conditions. Bacterial survival, seedling growth (dry weight), and biochemical endpoints (photosynthetic pigments, soluble and insoluble carbohydrates, proline, lipid peroxidation, protein, electron transport system, and superoxide dismutase) were evaluated. Results showed that the simultaneous exposure to GO and Rhizobium sp. E20-8 was able to alleviate the stress induced by drought on maize seedlings through osmotic and antioxidant protection by GO and mitigation of GO effects on the plant’s biochemistry by Rhizobium sp. E20-8. These results constitute a new lead on the development of biostimulant formulations to improve plant performance and increase food production in water-limited conditions. Full article

(This article belongs to the Special Issue Investigation and Development of Graphene Oxide-Based Materials)

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16 pages, 3705 KiB

Open AccessArticle

Preparation and Performance of Porous Carbon Nanocomposite from Renewable Phenolic Resin and Halloysite Nanotube

by Xiaomeng Yang, Xiaorui Zeng, Guihong Han, Dong Sui, Xiangyu Song and Yongsheng Zhang

Nanomaterials 2020, 10(9), 1703; https://doi.org/10.3390/nano10091703 - 29 Aug 2020

Cited by 14 | Viewed by 2690

Abstract

The growing demand for high performance from supercapacitors has inspired the development of porous nanocomposites using renewable and naturally available materials. In this work, a formaldehyde-free phenolic resin using monosaccharide-based furfural was synthesized to act as the carbon precursor. One dimensional halloysite nanotube [...] Read more.

The growing demand for high performance from supercapacitors has inspired the development of porous nanocomposites using renewable and naturally available materials. In this work, a formaldehyde-free phenolic resin using monosaccharide-based furfural was synthesized to act as the carbon precursor. One dimensional halloysite nanotube (HNT) with high porosity and excellent cation/anion exchange capacity was mixed with the phenol-furfural resin to fabricate carbonaceous nanocomposite HNT/C. Their structure and porosity were characterized. The effects of the halloysite nanotube amount and carbonization temperature on the electrochemical properties of HNT/C were explored. HNT/C exhibited rich porosity, involving a large specific surface area 253 m²·g⁻¹ with a total pore volume of 0.27 cm³·g⁻¹. The electrochemical performance of HNT/C was characterized in the three-electrode system and showed enhanced specific capacitance of 146 F·g⁻¹ at 0.2 A g⁻¹ (68 F·g⁻¹ for pristine carbon) in electrolyte (6 mol·L⁻¹ KOH) and a good rate capability of 62% at 3 A g⁻¹. It also displayed excellent cycle performance with capacitance retention of 98.5% after 500 cycles. The symmetric supercapacitors with HNT/C-1:1.5-800 electrodes were fabricated, exhibiting a high energy density of 20.28 Wh·Kg⁻¹ at a power density of 100 W·Kg⁻¹ in 1 M Na₂SO₄ electrolyte. The present work provides a feasible method for preparing composite electrode materials with a porous structure from renewable phenol-furfural resin and HNT. The excellent supercapacitance highlights the potential applications of HNT/C in energy storage. Full article

(This article belongs to the Special Issue Investigation and Development of Graphene Oxide-Based Materials)

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16 pages, 3681 KiB

Open AccessArticle

Green Graphene–Chitosan Sorbent Materials for Mercury Water Remediation

by Ana Bessa, Gil Gonçalves, Bruno Henriques, Eddy M. Domingues, Eduarda Pereira and Paula A. A. P. Marques

Nanomaterials 2020, 10(8), 1474; https://doi.org/10.3390/nano10081474 - 28 Jul 2020

Cited by 19 | Viewed by 3142

Abstract

The development of new graphene-based nanocomposites able to provide synergistic effects for the adsorption of toxic heavy metals in realistic conditions (environment) is of higher demand for future applications. This work explores the preparation of a green nanocomposite based on the self-assembly of [...] Read more.

The development of new graphene-based nanocomposites able to provide synergistic effects for the adsorption of toxic heavy metals in realistic conditions (environment) is of higher demand for future applications. This work explores the preparation of a green nanocomposite based on the self-assembly of graphene oxide (GO) with chitosan (CH) for the remediation of Hg(II) in different water matrices, including ultrapure and natural waters (tap water, river water, and seawater). Starting at a concentration of 50 μg L^–1, the results showed that GO–CH nanocomposite has an excellent adsorption capacity of Hg (II) using very small doses (10 mg L^–1) in ultrapure water with a removal percentage (% R) of 97 % R after only two hours of contact time. In the case of tap water, the % R was 81.4% after four hours of contact time. In the case of river and seawater, the GO–CH nanocomposite showed a limited performance due the high complexity of the water matrices, leading to a residual removal of Hg(II). The obtained removal of Hg(II) at equilibrium in river and seawater for GO–CH was 13% R and 7% R, respectively. Our studies conducted with different mimicked sea waters revealed that the removal of mercury is not affected by the presence of NO₃^– and Na⁺ (>90% R of Hg(II)); however, in the presence of Cl^–, the mercury removal was virtually nonexistent (1% R of Hg(II)), most likely because of the formation of very stable chloro-complexes of Hg(II) with less affinity towards GO–CH. Full article

(This article belongs to the Special Issue Investigation and Development of Graphene Oxide-Based Materials)

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16 pages, 3241 KiB

Open AccessArticle

Tuning the Nature of N-Based Groups From N-Containing Reduced Graphene Oxide: Enhanced Thermal Stability Using Post-Synthesis Treatments

by Stefania Sandoval and Gerard Tobias

Nanomaterials 2020, 10(8), 1451; https://doi.org/10.3390/nano10081451 - 24 Jul 2020

Cited by 11 | Viewed by 3165

Abstract

The synthesis of N-containing graphene derivatives by functionalization and doping of graphene oxide (GO) has been widely reported as an alternative to tune both their chemical and physical properties. These materials are of interest for a wide range of applications, including biomedicine, sensors, [...] Read more.

The synthesis of N-containing graphene derivatives by functionalization and doping of graphene oxide (GO) has been widely reported as an alternative to tune both their chemical and physical properties. These materials are of interest for a wide range of applications, including biomedicine, sensors, energy, and catalysis, to name some. Understanding the role of the nature, reactivity, concentration, and distribution of the N-based species, would pave the way towards the design of synthetic routes to obtain improved materials for specific applications. The N-groups can be present either as aliphatic fractions (amides and amines) or becoming part of the planar conjugated lattice (N-doping). Here, we have modified the distribution of N-based moieties present in N-containing RGO samples (prepared by ammonolysis of GO) and evaluated the role of the concentration and nature of the species in the thermal stability of the materials once thermally annealed (500–1050 °C) under inert environments. After these post-synthesis treatments, samples underwent marked structural modifications that include the elimination and/or transformation of N-containing fractions, which might account for the observed enhanced thermal stability. It is remarkable the formation of pyridinic N-oxide species, which role in the properties of N-containing graphene derivatives has been barely reported. The presence of this fraction is found to confer an enhanced thermal stability to the material. Full article

(This article belongs to the Special Issue Investigation and Development of Graphene Oxide-Based Materials)

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16 pages, 2576 KiB

Open AccessArticle

Removal and Recovery of Methyl Tertiary Butyl Ether (MTBE) from Water Using Carbon Nanotube and Graphene Oxide Immobilized Membranes

by Worawit Intrchom, Sagar Roy and Somenath Mitra

Nanomaterials 2020, 10(3), 578; https://doi.org/10.3390/nano10030578 - 22 Mar 2020

Cited by 14 | Viewed by 3888

Abstract

Methyl tert-butyl ether (MTBE) is a widely used gasoline additive that has high water solubility, and is difficult to separate from contaminated ground and surface waters. We present the development in functionalized carbon nanotube-immobilized membranes (CNIM-f) and graphene oxide-immobilized membranes (GOIM) for enhanced [...] Read more.

Methyl tert-butyl ether (MTBE) is a widely used gasoline additive that has high water solubility, and is difficult to separate from contaminated ground and surface waters. We present the development in functionalized carbon nanotube-immobilized membranes (CNIM-f) and graphene oxide-immobilized membranes (GOIM) for enhanced separation of MTBE via sweep gas membrane distillation (SGMD). Both types of modified membranes demonstrated high performance in MTBE removal from its aqueous mixture. Among the membranes studied, CNIM-f provided the best performance in terms of flux, removal efficiency, mass transfer coefficients and overall selectivity. The immobilization f-CNTs and GO altered the surface characteristics of the membrane and enhanced partition coefficients, and thus assisted MTBE transport across the membrane. The MTBE flux reached as high as 1.4 kg/m² h with f-CNTs, which was 22% higher than that of the unmodified PTFE membrane. The maximum MTBE removal using CNIM-f reached 56% at 0.5 wt % of the MTBE in water, and at a temperature of 30 °C. With selectivity as high as 60, MTBE recovery from contaminated water is very viable using these nanocarbon-immobilized membranes. Full article

(This article belongs to the Special Issue Investigation and Development of Graphene Oxide-Based Materials)

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23 pages, 2883 KiB

Open AccessArticle

Exposure of Smaller and Oxidized Graphene on Polyurethane Surface Improves its Antimicrobial Performance

by Inês Borges, Patrícia C. Henriques, Rita N. Gomes, Artur M. Pinto, Manuel Pestana, Fernão D. Magalhães and Inês C. Gonçalves

Nanomaterials 2020, 10(2), 349; https://doi.org/10.3390/nano10020349 - 18 Feb 2020

Cited by 19 | Viewed by 4320

Abstract

Catheter-related infections are a common worldwide health problem, highlighting the need for antimicrobial catheters. Here, antibacterial potential of graphene nanoplatelets (GNP) incorporated in the commonly used polymer for catheter manufacture—polyurethane (PU)—is investigated. Two strategies are explored: melt-blending, producing a composite, and dip coating, [...] Read more.

Catheter-related infections are a common worldwide health problem, highlighting the need for antimicrobial catheters. Here, antibacterial potential of graphene nanoplatelets (GNP) incorporated in the commonly used polymer for catheter manufacture—polyurethane (PU)—is investigated. Two strategies are explored: melt-blending, producing a composite, and dip coating, where a composite layer is deposited on top of PU. GNP with different lateral sizes and oxidation degrees—GNP-M5, GNP-M15, GNP-M5ox, GNP-M15ox—are applied in both strategies, and the antimicrobial potential towards Staphylococcus epidermidis of GNP dispersions and GNP-containing PU evaluated. As dispersions, oxidized and smaller GNP powders (GNP-M5ox) inhibit 74% bacteria growth at 128 µg/mL. As surfaces, GNP exposure strongly impacts their antimicrobial profile: GNP absence at the surface of composites yields no significant effects on bacteria, while by varying GNP: PU ratio and GNP concentration, coatings enhance GNP exposure, depicting an antimicrobial profile. Oxidized GNP-containing coatings induce higher antibacterial effect than non-oxidized forms, particularly with smaller GNPox, where a homogeneous layer of fused platelets is formed on PU, leading to 70% reduction in bacterial adhesion and 70% bacterial death. This pioneering work unravels how to turn a polymer clinically used to produce catheters into an antimicrobial surface, crucial to reducing risk of infection associated with catheterization. Full article

(This article belongs to the Special Issue Investigation and Development of Graphene Oxide-Based Materials)

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Review

Jump to: Research

32 pages, 2049 KiB

Open AccessReview

Graphene Derivatives in Biopolymer-Based Composites for Food Packaging Applications

by Ana Barra, Jéssica D. C. Santos, Mariana R. F. Silva, Cláudia Nunes, Eduardo Ruiz-Hitzky, Idalina Gonçalves, Selçuk Yildirim, Paula Ferreira and Paula A. A. P. Marques

Nanomaterials 2020, 10(10), 2077; https://doi.org/10.3390/nano10102077 - 21 Oct 2020

Cited by 45 | Viewed by 8007

Abstract

This review aims to showcase the current use of graphene derivatives, graphene-based nanomaterials in particular, in biopolymer-based composites for food packaging applications. A brief introduction regarding the valuable attributes of available and emergent bioplastic materials is made so that their contributions to the [...] Read more.

This review aims to showcase the current use of graphene derivatives, graphene-based nanomaterials in particular, in biopolymer-based composites for food packaging applications. A brief introduction regarding the valuable attributes of available and emergent bioplastic materials is made so that their contributions to the packaging field can be understood. Furthermore, their drawbacks are also disclosed to highlight the benefits that graphene derivatives can bring to bio-based formulations, from physicochemical to mechanical, barrier, and functional properties as antioxidant activity or electrical conductivity. The reported improvements in biopolymer-based composites carried out by graphene derivatives in the last three years are discussed, pointing to their potential for innovative food packaging applications such as electrically conductive food packaging. Full article

(This article belongs to the Special Issue Investigation and Development of Graphene Oxide-Based Materials)

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