Search Results (2,757)

Graphene oxide (GO) and reduced graphene oxide (rGO) have solidified their role as cornerstone nanomaterials in the pursuit of sustainable technology. This review synthesizes recent advances in harnessing the unique properties of GO and rGO such as their tunable surface chemistry and exceptional electrical conductivity for applications spanning environmental remediation and energy storage. In the environmental domain, they function as superior adsorbents and catalysts for the removal of hazardous pollutants. Concurrently, in the energy sector, their integration into supercapacitors and battery electrodes significantly enhances energy and power density. The adaptability of these materials also facilitates the creation of highly sensitive sensors and biosensors. However, the transition from laboratory research to widespread industrial application is hindered by challenges in scalable production, environmental health and safety concerns, and long-term stability. This review enhances the understanding of GO and rGO’s diverse applications and paves the way for future sustainable technologies in energy and environmental sectors. Full article

This paper presents the optimization of surface modification for aptameric graphene nanosensors for the measurement of biomarkers in undiluted physiological media. In these sensors, graphene transduces the binding between an aptamer and the intended target biomarker into a measurable signal while being coated with a polyethylene glycol (PEG) nanolayer to minimize nonspecific adsorption of matrix molecules. We perform a systematic study of the aptamer and PEG attachment schemes and parameters, including the impact of the serial or parallel PEG–aptamer attachment scheme, PEG molecular weight and surface density, and aptamer surface density on the sensor behavior, such as the responsivity to biomarker concentration changes, and importantly, they are used for operation in physiological media and have the ability to reject nonspecific binding to interfering molecules. We then use the understanding from this parametric study to identify graphene nanosensor designs that are optimally functionalized with PEG and aptamers to be strongly responsive to target biomarkers and effectively reduce nonspecific adsorption of interferents, thereby enabling sensitive and specific biomarker measurements in undiluted physiological media. The experimental results show that nanosensors that were optimized via serial modification with 5000 Da PEG at 15 mM and a 94 nt DNA aptamer at 500 nM allowed specific measurement of C-reactive protein (CRP) in undiluted human serum with a limit of detection (LOD) down to 27 pM, representing an up to 1000-fold improvement compared to previously reported CRP measurements. Full article

To address the corrosion and degradation of metallic materials in seawater, tidal, and similar environments, this study employs lysine (C₆H₁₄N₂O₂) to modify graphene oxide (GO) via a hydrothermal process. The modified graphene oxide (f-GO) and poly(l-lysine) (PL) composite was characterized structurally and functionally using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) to characterize its structure and properties. A composite coating was prepared using modified graphene oxide (f-GO) and polyurethane (PU), which underwent electrochemical testing, hardness testing, corrosion rate testing, adhesion testing, impact resistance testing, and salt spray corrosion resistance testing. Experimental results indicate that C-N stretching vibration peaks appeared at all reaction temperatures. At 85 °C, f-GO85 exhibited optimal modification with a layer spacing of 1.471 nm, 72% transmittance, and superior thermal stability, confirming successful lysine grafting onto the GO surface. Corrosion resistance testing of the composite coating revealed enhanced adhesion and impact resistance, reduced corrosion rate, decreased corrosion current density in polarization curves, positive shift in corrosion potential, and higher impedance values in impedance curves, indicating improved coating density and corrosion resistance. Salt spray tests demonstrated that incorporating lysine-modified graphene oxide significantly improved the anti-corrosion performance of polyurethane coatings. Optimal corrosion resistance was achieved when the modified graphene oxide content was 0.2 wt%. Full article

Electric-field-sensitive dielectrics play a crucial role in electric field induction sensing and related capacitive conversion, with interfacial polarization and charge accumulation largely determining the signal output. This paper introduces graphene/transition metal dichalcogenide (TMD) (MoSe₂, MoS₂, and WS₂) heterojunctions as functional fillers to enhance the dielectric response and electric-field-induced voltage output of flexible polydimethylsiloxane (PDMS) composites. Density functional theory (DFT) calculations were used to evaluate the stability of the heterojunctions and interfacial electronic modulation, including binding behavior, charge redistribution, and Fermi level-referenced band structure/total density of states (TDOS) characteristics. The calculations show that the graphene/TMD interface is primarily controlled by van der Waals forces, exhibiting negative binding energy and significant interfacial charge rearrangement. Based on these theoretical results, graphene/TMD heterojunction powders were synthesized and incorporated into polydimethylsiloxane (PDMS). Structural characterization confirmed the presence of face-to-face interfacial contacts and consistent elemental co-localization within the heterojunction filler. Dielectric spectroscopy analysis revealed an overall improvement in the dielectric constant of the composite materials while maintaining a stable loss trend within the studied frequency range. More importantly, calibrated electric field induction tests (based on pure PDMS) showed a significant enhancement in the voltage response of all heterojunction composite materials, with the WS₂-G/PDMS system exhibiting the best performance, exhibiting an electric-field-induced voltage amplitude 7.607% higher than that of pure PDMS. This work establishes a microscopic-to-macroscopic correlation between interfacial electronic modulation and electric-field-sensitive dielectric properties, providing a feasible interface engineering strategy for high-performance flexible dielectric sensing materials. Full article

This study theoretically investigates the nonlinear optical response of asymmetric dielectric structures embedded with graphene and demonstrates tunable optical bistability in the terahertz frequency range. Our findings reveal that the bistable behavior can be effectively modulated by varying the incident angle, the working wavelength, and the thickness and permittivity of the dielectric layers. In symmetric dielectric configurations, transmittance is enhanced, whereas in asymmetric structures, it is reduced. The thresholds of optical bistability decrease with increasing wavelength of the incident light, while they increase with thicker dielectric layers or higher permittivity of the dielectric medium. Furthermore, widening the bistability range can be achieved by increasing the incident angle. The proposed asymmetric graphene–dielectric layered structure offers a promising platform for the development of advanced terahertz active photonic devices, including optical modulators, optical switches, and mid-infrared functional components. Full article

This study utilizes QM/MM Born–Oppenheimer Molecular Dynamics in order to model the process of intermolecular binding between reduced graphene oxide (rGO) and butadiene–acrylonitrile copolymer (PBDAN) with a monomer ratio of 2:1. This research aims to elucidate the structural reasons behind the enhancing properties of the substrate, focusing on the polymer matrix. The behavior of each phase was examined and discussed. More importantly, the intermolecular interactions within the interphase zone of adsorption were investigated on an atomic scale. We found and characterized 58 such instances, grouped into hydrogen bonds and three types of stacking: π–π, σ–π, and σ–n. Each occurrence was analyzed through the use of radial distribution functions. Five spontaneous chemical processes within the rGO nanoparticle were modeled and characterized. Two of them were found to provide stabilization only within the substrate, while the rest are relevant for the overall constitution of the heteromaterial. Perhaps most intriguing is the process of self-repair as part of the vacancy defect. This occurs entirely within the carbon frame of the rGO layer. We believe our results to be of importance for a large set of ligand materials, mostly those which contain unsaturated bonds and electronegative atoms. Full article

Pancreatic function tests are used to determine the presence of chronic pancreatitis, particularly in the early stage of the disease. Chymotrypsin is an indicator of pancreatic function and is thus related to pancreatic diseases. However, these methods often require specific equipment and cannot always meet on-site analysis requirements. Consequently, a highly sensitive detection method needs to be developed. This research employed graphene oxide modified with NHS sensors and peptides (RRHFFGC: Arginine-Arginine-Histidine-Phenylalanine-Phenylalanine-Glycine-Cysteine) tagged with gold nanoclusters (Au NCs) for the detection of chymotrypsin. The N-Hydroxysuccinimide-(Polyethylene Glycol)₄-Dibenzocyclooctyne (NHS-PEG₄-DBCO) and graphene oxide (GO)-N₃ click reaction yielded GO-NHS material, appropriate for fluorescence quenching. The peptide chain was accurately broken with the introduction of chymotrypsin, and the Au NCs were situated far from the GO-NHS surface. The detection limit was 2.014 pg/mL. The results showed that the detection method had high sensitivity in comparison with the previous studies. This method is relevant to real samples due to its potential efficacy. Therefore, it is a promising method in the biomedical field. Full article

Graphene (GRA) and graphene oxide (GO) have drawn significant attention in materials science, chemistry, and nanotechnology because of their tunable physicochemical properties and wide range of potential uses in biomedical and environmental applications. Building reliable, large-scale molecular models of GRA and GO is essential for molecular simulations of wetting, adsorption, and catalytic behavior. However, current methods often struggle to generate large, chemically consistent sheets at high oxidation levels. In addition, the resulting structures are frequently incompatible across different simulation packages. This work introduces a step-by-step protocol with custom Tool Command Language (Tcl) and modified Python version 3.12 scripts for building large-scale, AMBER-compatible GO structures with oxidation levels from 0% to 68%. The workflow applies a systematic surface modification strategy combined with post-processing and atom-type assignment routines to ensure chemical accuracy and force field consistency. The dataset includes fifteen MOL2 format files of 20 × 20 nm² GO sheets, ranging from pristine to highly oxidized surfaces, each validated through oxidation-ratio analysis and structural integrity checks. Together, the dataset and protocol provide a design of scalable and chemically reliable GO molecular models for molecular dynamics simulations. Full article

This review provides a comprehensive analysis of modern strategies for the synthesis, functionalization, and application of carbon nanotubes (CNTs) and graphene for the development of high-performance polymer composites in the field of strain sensing. The paper systematically organizes key synthesis methods for CNTs and graphene (chemical vapor deposition (CVD), such as arc discharge, laser ablation, microwave synthesis, and flame synthesis, as well as approaches to their chemical and physical modification aimed at enhancing dispersion within polymer matrices and strengthening interfacial adhesion. A detailed examination is presented on the structural features of the nanofillers, such as the CNT aspect ratio, graphene oxide modification, and the formation of hybrid 3D networks and processing techniques, which enable the targeted control of the nanocomposite’s electrical conductivity, mechanical strength, and flexibility. Central focus is placed on the fundamental mechanisms of the piezoresistive response, analyzing the role of percolation thresholds, quantum tunneling effects, and the reconfiguration of conductive networks under mechanical load. The review summarizes the latest advancements in flexible and stretchable sensors capable of detecting both micro- and macro-strains for structural health monitoring, highlighting the achieved improvements in sensitivity, operational range, and durability of the composites. Ultimately, this analysis clarifies the interrelationship between nanofiller structure (CNTs and graphene), processing conditions, and sensor functionality, highlighting key avenues for future innovation in smart materials and wearable devices. Full article

Integrating antibacterial fabrics into wearable technology represents a transformative advancement in healthcare, fashion, and personal hygiene. Antibacterial fabrics, designed to inhibit microbial growth, are gaining prominence due to their potential to reduce infections, enhance durability, and maintain cleanliness in wearable devices. These fabrics offer effective antimicrobial properties while retaining comfort and functionality by incorporating nanotechnology and advanced materials, such as silver nanoparticles, zinc oxide, titanium dioxide, and graphene. The production techniques for antibacterial textiles range from chemical and physical surface modifications to biological treatments, each tailored to achieve long-lasting antibacterial performance while preserving fabric comfort and breathability. Advanced methods such as nanoparticle embedding, sol–gel coating, electrospinning, and green synthesis approaches have shown significant promise in enhancing antibacterial efficacy and material compatibility. Wearable technology, including fitness trackers, smart clothing, and medical monitoring devices, relies on prolonged skin contact, making the prevention of bacterial colonization essential for user safety and product longevity. Antibacterial fabrics address these concerns by reducing odor, preventing skin irritation, and minimizing the risk of infection, especially in medical applications such as wound dressings and patient monitoring systems. Despite their potential, integrating antibacterial fabrics into wearable technology presents several challenges. This review provides a comprehensive overview of the key antibacterial agents, the production strategies used to fabricate antibacterial textiles, and their emerging applications in wearable technologies. It also highlights the need for interdisciplinary research to overcome current limitations and promote the development of sustainable, safe, and functional antibacterial fabrics for next-generation wearable. Full article

Carbon nanotube (CNT) and graphene-reinforced nanocomposites have become exceptional multifunctional materials because of their exceptional mechanical, thermal, and electrical properties. Recent developments in synthesis methods, dispersion strategies, and interfacial engineering have effectively overcome agglomeration-related limitations by significantly improving filler distribution, matrix compatibility, and load-transfer efficiency. These nanocomposites have better wear durability, corrosion resistance, and surface properties like super-hydrophobicity. A comparative analysis of polymer, metal, and ceramic matrices finds benefits for applications in biomedical, construction, energy, defense, and aeronautics. Functionally graded architecture, energy-harvesting nanogenerators, and additive manufacturing are some of the new fabrication processes that enhance design flexibility and functional integration. In recent years, scalability, life-cycle evaluation, and environmentally friendly processing have all gained increased attention. The development of next-generation, high-performance graphene and carbon nanotube (CNT)-based nanocomposites is critically reviewed in this work, along with significant obstacles and potential next steps. Full article

The objective of this study was to use Density Functional Theory (DFT) calculations to examine how boron doping modulates the electronic properties of graphene quantum dots (GQDs) and their interaction with the Hg²⁺ ion. Boron doping decreases the HOMO-LUMO gap and increases the GQD’s electrophilic character, facilitating charge transfer to the metal ion. The adsorption energy results were negative, indicating electronic stabilization of the combined systems, without implying thermodynamic favorability, with the GQD@3B_Hg²⁺ system being the strongest at −349.52 kcal/mol. The analysis of global parameters (chemical descriptors) and the study of non-covalent interactions (NCIs) supported the affinity of Hg²⁺ for doped surfaces, showing that the presence of a single boron atom contributes to clear attractive interactions. In general, configurations doped with 1 or 2 boron atoms exhibit satisfactory performance, demonstrating that boron doping effectively modulates the reactivity and adsorption properties of GQD for efficient Hg²⁺ capture. Full article

Poly (3,4-ethylenedioxythiophene polystyrene sulfonate) (PEDOT:PSS) is a solution-processable hole transport layer known for its high work function and excellent hole mobility. The incorporation of graphene serves as an effective strategy to augment the hole-transport properties of PEDOT:PSS. In this study, the electronic structure of graphene-doped PEDOT:PSS (G-PEDOT:PSS) was investigated using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). It was found that the work function of PEDOT:PSS increases with graphene doping concentration, rising from 4.86 eV for undoped PEDOT:PSS to 5.03 eV for PEDOT:PSS incorporating 10 wt% graphene. The impact of this modification on the energy-level alignment with zinc phthalocyanine (ZnPc), which is a prototypical p-type organic semiconductor, was examined through in situ XPS and UPS analyses. Despite the increased work function, the hole injection barriers for both PEDOT:PSS and G-PEDOT:PSS to ZnPc were determined to be identical at 0.26 eV. This lack of change in the barrier is explicitly attributed to Fermi-level pinning, where the integer charge transfer level of ZnPc is pinned to the Fermi level of the substrate, preventing a further reduction in the energy offset. That said, for other p-type organic semiconductors with higher ionization energies, the use of G-PEDOT:PSS could potentially enable more efficient hole injection. Full article

Lithium–sulfur batteries (LSBs) are a promising emerging technology due to their high energy density, low-cost materials, and safety. However, their environmental sustainability is not yet well understood. This study conducted a prospective life cycle assessment (LCA) on two patented LSB models, using data from patents as the inventory: one with a standard sulfur cathode and another with a graphene–sulfur composite (GSC). The assessment is conducted for a functional unit of 1 Wh of produced electricity, adopting a cradle-to-gate system boundary and a prospective time horizon set to 2035. The LSB GSC model battery showed significantly better performance in terms of climate change and fossil depletion, with a 42% lower impact, mainly due to a reduction in the lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) content from 1205 mg Wh⁻¹ to 250 mg Wh⁻¹. However, the GSC model also had significant drawbacks, showing a 93% higher metal depletion and 49% higher water depletion than the standard sulfur battery. Building on an established patent-based prospective LCA approach, this work applies patent-derived quantitative inventories and patent-informed eco-design analysis to support environmentally informed design decisions for emerging LSB technologies prior to large-scale commercialization. Full article

The global surge in illicit drug use has intensified the demand for rapid, portable, and reliable on-site detection technologies. Traditional analytical approaches, such as laboratory-based instrumentation and biological sample assays, while accurate, are often constrained by high costs, long processing times, and the need for specialized equipment, rendering them unsuitable for field applications. This review highlights recent progress in chemical sensor technologies designed for the detection of widely misused drugs such as methamphetamine, cocaine, fentanyl, and heroin. Parallel advancements in the detection of environmental contaminants, particularly concerning micro- and nanoplastics, are also discussed. Emerging sensing platforms employing nanoparticle functionalization, graphene nanosheets, MXenes, metal–organic frameworks (MOFs), and supramolecular colorimetric assays demonstrate significant potential for achieving high sensitivity, selectivity, and operational simplicity in portable formats. These innovations enable real-time detection with minimal user expertise, thereby advancing applications in forensic analysis, environmental monitoring, and public health protection. The review also addresses current limitations related to detection accuracy, reagent stability, and matrix interferences and proposes future directions for optimizing sensor robustness and performance under diverse field conditions. Full article