Nanodiamond Research Articles

Refractometric method to study the coating thickness of diamond nanoparticles

A method based on refractometric measurements of liquid nanodisperse systems has been developed to determine the quantitative composition of diamond-amorphous carbon colloidal particles. It was demonstrated that by measuring the changes in the refractive index and density of sols caused by changes in particle concentration it is possible to determine the thickness of the particle surface layer, assuming its composition is known. Within the framework of the Mie theory, the influence of the size of diamond particles with carbon coating on the refractive index of hydrosols was quantified. The limits of applicability of the developed method have been determined. For several polydisperse sols with coated diamond particles the thickness of carbon coating was determined.

Optimization of the properties of nematic matrix suspended with subtle quantities of the nanoparticles for improved alignment and operating voltage

ABSTRACT The current study examines and reflects the effect of minute quantity of Diamond nanoparticles (DNPs) in the Nematic liquid crystal (NLC) matrix. A well structured and strategized study is performed in order to get a deep understanding about the interactions that might have taken place between the guests and the hosts. Our study professed a significant alteration in the number of parameters of guest-host system in comparison to the pure liquid crystal (LC) matrix that could be found extremely promising for the display devices and low-power switching machines. 0.05, 0.07 and 0.1 wt/wt% concentrations of the NPs incorporated in the LC matrix and the composites are prepared with the high precision weight measurement using electrical balance. Dielectric spectrum is catalogued for both the homogeneous and vertical alignments of sample cells. Threshold voltage and operating voltage are found to be significantly decreased for 0.05 wt/wt% composite. Response time for the prepared composites is profoundly abated which is a crucial factor for the fast response devices. Careful examination of pretilt angles is executed and an improvement in the alignment is found as one more perk of this study.

Advanced electrochemical sensing of cyanuric acid: An integration of transition metal dichalcogenides, copper and diamond nanoparticles

In the present study, we demonstrate the synergistic effect of copper nanoparticles, tungsten disulfide, and diamond nanoparticles on the electrochemical detection of cyanuric acid, a compound conventionally employed for disinfection in aquatic recreational facilities such as swimming pools. First, copper nanoparticles were synthesized in-situ on a glassy carbon electrode through the electrochemical reduction of copper nitrate and their response towards cyanuric acid was assessed. In order to improve this response, we evaluated the inclusion of transition metal dichalcogenides nanosheets (MoS2, ReS2 or WS2), as well as diamond nanoparticles in the electrochemical sensor construction. These nanomaterials were incorporated onto the electrode via drop-casting from their respective suspensions. Specifically, the 2D transition metal dichalcogenide suspensions were obtained through a top-down exfoliation method, facilitated by ultrasonic assistance. After optimizing the arrangement of nanomaterials on the glassy carbon electrode to enhance cyanuric acid detection, we characterized the morphology of the resulting surfaces at each stage of electrode surface modification by atomic force microscopy and scanning electron microscopy. The optimized methodology revealed that the sensor response exhibited a linear relationship with cyanuric acid concentrations ranging from 0.077 to 0.70 mM with a detection limit of 23 µM. The sensor was applied to cyanuric acid determination in a swimming pool water sample, obtaining very good recoveries. The results are in good agreement with those obtained by HPLC-UV–vis measurements.

Production of Cu/Diamond Composite Coatings and Their Selected Properties.

This article presents Cu/diamond composite coatings produced by electrochemical reduction on steel substrates and a comparison of these coatings with a copper coating without diamond nanoparticles (<10 nm). Deposition was carried out using multicomponent electrolyte solutions at a current density of 3 A/dm2 and magnetic stirring speed of 100 rpm. Composite coatings were deposited from baths with different diamond concentrations (4, 6, 8, 10 g/dm3). This study presents the surface morphology and structure of the produced coatings. The surface roughness, coating thickness (XRF), mechanical properties (DSI), and adhesion of coatings to substrates (scratch tests) were also characterized. The coatings were also tested to assess their solderability, including their spreadability, wettability of the solder, durability of solder-coating bonds, and a microstructure study.

Probing the 13C nuclear spin relaxation of diamond nanoparticles with solid-state NMR

Probing the 13C nuclear spin relaxation of diamond nanoparticles with solid-state NMR

Multifunctional Nanodiamond Interfacial Layer for Ultra‐Stable Zinc‐Metal Anodes

AbstractAchieving reversible plating/stripping of zinc (Zn) anodes is crucial in aqueous Zn‐ion batteries (AZIBs). However, undesired dendrite growth and parasitic side reactions severely deteriorate battery lifespan. The construction of stable protective coating is an effective strategy to enhance anode stability. In this study, a multifunctional nanodiamond (ND) inorganic layer is designed and constructed on both Zn and Cu electrodes that can both effectively inhibit dendrite growth and suppress Zn anode corrosion. Experimental results and theoretical calculations demonstrate that this artificial protective layer, with ultra‐high surface energy, enables the controlled creation of abundant nucleation sites (in the order of 1012 cm−2) for the homogenization of ion flux and electric field on the anode. It is found that zinc ions preferentially adhere to the diamond surfaces with lower diffusion barriers, leading to uniform zinc deposition. A symmetric cell with the ND‐protected Zn (Zn‐ND) anode exhibits reversible plating/stripping behavior for an impressive duration of over 3600 h at 1 mA cm−2. Furthermore, the MnO2||Zn full battery retains 90% of its initial capacity after 3500 cycles at 2 A g−1, and assembled hybrid capacitor operates smoothly over 65 000 cycles at 10 A g−1. These results underscore the potential of this coating as a promising solution for achieving highly stable Zn anodes for aqueous batteries.

A New Electrochemical Sensor for the Detection of Azithromycin using Screen‐Printed Carbon Electrode Modified with Boron‐Doped Diamond Nanoparticles and Reduced‐Graphene Oxide

AbstractExcessive use of azithromycin (AZM) is associated with resistance and negative impacts on the environment. Therefore, this study aimed to develop an electrochemical sensor for AZM. The screen‐printed carbon electrode (SPCE) modified with boron‐doped diamond nanoparticle (BDDNP) and reduced‐graphene oxide (rGO) was successfully applied to measure the AZM concentration. The morphology of the modified electrode was characterized by scanning electron microscopy‐energy dispersive X‐ray (SEM‐EDX). Furthermore, the effect of electrochemical parameters, such as signal per background, scan rate, and selectivity was determined. The results showed that under optimum conditions, the plot of AZM demonstrated linearity in the range of 30–100 μM with a limit of detection (LOD) at 1.6 μM. The repeatability and recovery were also investigated, and the sensor was applied to real samples obtained from hospital wastewater. A remarkable 93.27 % recovery rate and excellent precision were recorded with an %RSD of 2.41 %. This study underscores the potential of SPCE modified with rGO/BDDNP for accurate and reliable measurement of AZM levels, showcasing great applicability in addressing the challenges associated with monitoring AZM in various environmental settings.

Effects of adding nanodiamonds in mechanical properties of jute and ramie fiber reinforced epoxy composites

AbstractThe objective of this research is to investigate the potential impact of nanodiamond filler particles on the mechanical and morphological characteristics of epoxy composites that are fortified with ramie and jute fibers. Composed of composite laminates containing nanodiamonds at concentrations of 0.1, 0.3, and 0.5 wt. %, the laminates were produced via vacuum‐assisted resin infusion (VARI to evaluate the alterations in mechanical properties, Vickers hardness, tensile, and flexural tests were conducted on the prepared composites). The findings showed that adding 0.3 wt. % nanodiamonds to epoxy composites significantly improved the hardness of the composites about 18.56% and 34.38%, the tensile strength of the composites about 19.1% and 28.01%, and the flexural strength of the composites about 17.7% and 21.12% for ramie/epoxy and jute/epoxy, respectively. The optimal concentration of nanodiamonds for both types of fibers in order to optimize these properties was calculated to be 0.3 wt. % of nanodiamonds. A micro‐x‐ray CT scan was performed to determine the percentage of porosity in composites. The utilization of scanning electron microscopy (SEM) demonstrated that an increase in the nanodiamond content led to enhanced fiber dispersion and reduced interfacial voids. In contrast, Fourier transform infrared (FTIR) analysis unveils the hydrophobic characteristics, cellulose content, and improved interfacial bonding between the fibers and the epoxy matrix, which is attributed to the robust covalent bonding enabled by the nanodiamonds.Highlights Adding nanodiamonds (NDs) improved adhesion at fiber‐matrix interface. Mechanical properties peaked for composites with 0.3 wt. % of NDs. Beyond 0.3 wt. % of NDs, agglomerates in composites were observed through SEM. Void percent increased for composites with 0.5 wt. % of NDs.

MnO2-coated nanodiamond-driven photodynamic therapy for enhanced antitumor effect by addressing hypoxia and glutathione depletion

The generation of reactive oxygen species (ROS) at the tumor site to induce destruction is emerging as a novel strategy for cancer treatment, which involves photodynamic therapy (PDT). Nevertheless, tumors typically create a hypoxic environment and are equipped with an endogenous antioxidant defense system that could potentially impede the efficiency of the therapeutic approach. To overcome these drawbacks, herein, a tumor microenvironment-responsive the ND-PAA-CD-Ce6@MnO2 (NPCC@M) delivery system was fabricated by disulfide bond coupling chlorin e6 (Ce6) to nanodiamond (ND) and further wrapped by MnO2 nanosheets to facilitate PDT. The use of disulfide bond not only stabilizes Ce6 in the blood circulation to prevent premature leakage, but also destroys the antioxidant barrier of overexpressed glutathione (GSH) in tumor cells. Moreover, the outer MnO2 was rapidly degraded by the endogenous hydrogen peroxide (H2O2) in the acidic pH and GSH within the tumor cells, which leads to an abundance of O2 and while increases the level of 1O2 under laser irradiation. The results eventually broke the redox homeostasis and attenuate hypoxia, thereby inducing apoptosis and necrosis of tumor cells. Detailed in vitro and in vivo biological effect has revealed a good biosafety profile and a high tumor suppression effect. Such a novel ND-based system with tumor microenvironment-modulating capability to elevate oxygen content and promote GSH consumption in tumor cells opens new opportunities for enhanced ROS treatment paradigms.

Inward motion of diamond nanoparticles inside an iron crystal

In the absence of externally applied mechanical loading, it would seem counterintuitive that a solid particle sitting on the surface of another solid could not only sink into the latter, but also continue its rigid-body motion towards the interior, reaching a depth as distant as thousands of times the particle diameter. Here, we demonstrate such a case using in situ microscopic as well as bulk experiments, in which diamond nanoparticles ~100 nm in size move into iron up to millimeter depth, at a temperature about half of the melting point of iron. Each diamond nanoparticle is nudged as a whole, in a displacive motion towards the iron interior, due to a local stress induced by the accumulation of iron atoms diffusing around the particle via a short and easy interfacial channel. Our discovery underscores an unusual mass transport mode in solids, in addition to the familiar diffusion of individual atoms.

Release dynamics of nanodiamonds created by laser-driven shock-compression of polyethylene terephthalate

Laser-driven dynamic compression experiments of plastic materials have found surprisingly fast formation of nanodiamonds (ND) via X-ray probing. This mechanism is relevant for planetary models, but could also open efficient synthesis routes for tailored NDs. We investigate the release mechanics of compressed NDs by molecular dynamics simulation of the isotropic expansion of finite size diamond from different P-T states. Analysing the structural integrity along different release paths via molecular dynamic simulations, we found substantial disintegration rates upon shock release, increasing with the on-Hugnoiot shock temperature. We also find that recrystallization can occur after the expansion and hence during the release, depending on subsequent cooling mechanisms. Our study suggests higher ND recovery rates from off-Hugoniot states, e.g., via double-shocks, due to faster cooling. Laser-driven shock compression experiments of polyethylene terephthalate (PET) samples with in situ X-ray probing at the simulated conditions found diamond signal that persists up to 11 ns after breakout. In the diffraction pattern, we observed peak shifts, which we attribute to thermal expansion of the NDs and thus a total release of pressure, which indicates the stability of the released NDs.

Optically detected magnetic resonance study of thermal effects due to absorbing environment around nitrogen-vacancy-nanodiamond powders

We implanted Fe+ ions in nanodiamond (ND) powder containing negatively charged nitrogen-vacancy (NV−) centers and studied their Raman spectra and optically detected magnetic resonance (ODMR) in various applied magnetic fields with green light (532 nm) excitation. In Raman spectra, we observed a blue shift of the NV− peak associated with the conversion of the electronic sp3 configuration to the disordered sp2 one typical for the carbon/graphite structure. In the ODMR spectra, we observed a red shift of the resonance position caused by local heating by an absorptive environment that recovers after annealing. To reveal the red shift mechanism in ODMR, we created a controlled absorptive environment around ND by adding iron-based Fe2O3 and graphitic sp2 powders to the ND suspension. This admixture caused a substantial increase in the observed shift proportional to the applied laser power, corresponding to an increase in the local temperature by 150–180 K. This surprisingly large shift is absent in non-irradiated NV-ND powders, is associated only with the modification of the local temperature by the absorptive environment of NV-NDs, and can be studied using ODMR signals of NV−.

Characterization of surface and bulk properties of α-Tocopherol blended and γ irradiated UHMWPE sandwich nanocomposites

In the present study, an unconventional approach in compression molding is chosen to fabricate Ultra High Molecular Weight Polyethylene (UHMWPE) sandwich composites with Graphene (Gr) and Nano-diamond (ND) as fillers. A unique comparison is done between the surface and bulk properties of UHMWPE nano-composites and UHMWPE sandwich composites. Influence of gamma irradiation at doses of 50, 100 kGy doses and vitamin E (vit-E) on crystal structure, mechanical, thermal and tribological characteristics of UHMWPE composites were studied through x-ray diffraction (XRD), raman spectroscopy, dynamic mechanical analysis (DMA), rheology, differential scanning calorimetry (DSC), tensile, nano-indentation and wear characterization techniques. Fracture regions and surface wear of the samples were analysed through scanning electron microscopy (SEM) to understand the dispersion behavior of fillers in matrix. The concentration of vit-E content in UHMWPE greatly influenced the crosslinks and surface properties in gamma irradiated composites. Gamma irradiation have shown significant improvement in crystallinity, viscous behavior and bulk properties of UHMWPE composites. Irradiated UHMWPE nano-composites have shown better tensile results when compared with sandwich composites, with 22 % increase in young's modulus and 16 % increase in yield stress. Wear rate has been reduced by 25 % for irradiated sandwich UHMWPE composites when compared with UHMWPE nano-composites.

Novel Hybrid Ferromagnetic Fe–Co/Nanodiamond Nanostructures: Influence of Carbon on Their Structural and Magnetic Properties

This study introduces a novel magnetic nanohybrid material consisting of ferromagnetic (FM) bcc Fe–Co nanoparticles (NPs) grown on nanodiamond (ND) nanotemplates. A combination of wet chemistry, which produces chemical precursors and their subsequent thermal treatment under vacuum, was utilized for its development. The characterization and study of the prepared samples performed with a range of specialized experimental techniques reveal that thermal treatment of the as-prepared hybrid precursors under a range of annealing conditions leads to the development of Co-rich Fe–Co alloy NPs, with average sizes in the range of 6–10 nm, that exhibit uniform distribution on the surfaces of the ND nanotemplates and demonstrate FM behavior throughout a temperature range from 2 K to 400 K, with maximum magnetization values ranging between 18.9 and 21.1 emu/g and coercivities ranging between 112 and 881 Oe. Moreover, 57Fe Mössbauer spectroscopy reveals that apart from the predominant bcc FM Fe–Co phase, iron atoms also participate in the formation of a secondary martensitic-type Fe–Co phase. The emergence of this distinctive phase is attributed to the diffusion of carbon atoms within the Fe–Co lattices during their formation at elevated temperatures. The source of these carbon atoms is related to the unique morphological properties of the ND growth matrices, which facilitate surface sp2 formations. Apart from their diffusion within the Fe–Co NP lattice, the carbon atoms also reconstruct layered graphitic-type nanostructures enveloping the metallic alloy NPs. These non-typical nanohybrid materials, reported here for the first time in the literature, hold significant potential for use in applications related, but not limited to, biomedicine, biopharmaceutics, catalysis, and other various contemporary technological fields.

Role of stacking sequence, metal sheets, and nano particle on strength and toughness of FMLs

The effect of nano particle inclusion and the stacking sequence/metal volume fraction on the tensile strength and energy absorption properties of Fiber Metal Laminates (FML) is investigated. The FML structure is composed of lightweight thin sheets of aerospace grade aluminum alloy 7075 and unidirectional glass fiber composite sheets with Araldite LY5052 thermoset epoxy system as the matrix. The volume fraction of aluminum sheets in the FML structure was varied by increasing the number of aluminum sheets from 2 to maximum 4. In the second batch, the epoxy matrix is reinforced with of multi-walled carbon nano tubes and nano diamond particles together, each with 0.15 wt%. The purpose is to enhance the properties of the epoxy matrix to facilitate higher inter-laminate adhesion (FRP and aluminum). The results of the tensile testing show that with the increase of the metal volume fraction, the tensile strength as well energy absorbing capability (toughness) both are increased. The inclusion of the nano-reinforcements has increased the tensile strength and the toughness of the FML structure as compared to that of the FMLs without nano particles. The strength-to-weight ratio of FML structures is also increased after the inclusion of nano reinforced as desired for aerospace applications.

Nanodiamonds and natural deep eutectic solvents as potential carriers for lipase

This study investigates the use of nanodiamonds (ND) as a promising carrier for enzyme immobilization and compares the effectiveness of immobilized and native enzymes. Three different enzyme types were tested, of which Rhizopus niveus lipase (RNL) exhibited the highest relative activity, up to 350 %. Under optimized conditions (1 h, pH 7.0, 40 °C), the immobilized ND-RNL showed a maximum specific activity of 0.765 U mg−1, significantly higher than native RNL (0.505 U mg−1). This study highlights a notable enhancement in immobilized lipase; furthermore, the enzyme can be recycled in the presence of a natural deep eutectic solvent (NADES), retaining 76 % of its initial activity. This aids in preserving the native conformation of the protein throughout the reusability process. A test on brine shrimp revealed that even at low concentrations, ND-RNL had minimal toxicity, indicating its low cytotoxicity. The in silico molecular dynamics simulations performed in this study offer valuable insights into the mechanism of interactions between RNL and ND, demonstrating that RNL immobilization onto NDs enhances its efficiency and stability. All told, these findings highlight the immense potential of ND-immobilized RNL as an excellent candidate for biological applications and showcase the promise of further research in this field.

Synergistic effect of Silver-Nanodiamond composite as an efficient antibacterial agent against E. coli and S. aureus

Bacterial antimicrobial resistance (BAMR) seems to pose the greatest threat to public health, food safety, and agriculture in this century. The development of novel efficient antimicrobial agents to combat bacterial infections has become a global issue. Silver nanoparticles (Ag NPs) appeared as a feasible alternative to antibiotics. However, Ag NPs face cost, toxicity, and aggregation issues which limit their antibacterial activity. This work aims to stabilize Ag NPs with enhanced antimicrobial activity at comparatively lower Ag concentrations to prevent bacterial infections. For this purpose, the Ag core was covered with nanodiamonds (NDs). Ag-NDs composite have been synthesized by microplasma technique. TEM analysis confirmed the presence of both Ag and NDs in the Ag-NDs composite. A particle size (∼19 nm) was reported for Ag-NDs at the highest concentration as compared to Ag NPs (∼3 nm). The conduction band of the diamond acted as an extremely strong reducing agent for Ag NPs. The large surface area of NDs stabilized the Ag NPs. A redshift (∼400 nm–406 nm) in UV–visible spectra of the Ag-NDs composite indicated the formation of bigger-sized Ag NPs after incorporating NDs. XRD and LIBS analysis verified the increase in intensity of Ag-NPs by increasing ND concentration. The presence of functional groups including OH, CH, and Ag/Ag2O was confirmed by FTIR. Bacterial inhibition growth appeared to be a dose-dependent process. The minimum inhibition concentration value of Ag-NDs composite at the highest NDs concentration against E. coli (∼ 0.69 μg/ml) and S. aureus (∼44 μg/ml). This is the first study to report the smallest MIC for E. coli (<1 μg/ml). Ag-ND composites emerged to be more efficient than Ag NPs and preferred to be used against BAMR. The enhanced antibacterial activity of the Ag-NDs composite makes it a potential candidate for antibiotics, food products, and pesticides.

Synergistic effect of graphene and nanodiamonds to achieve ultra-low friction on rough DLC coatings

Diamond-like carbon (DLC) with its protective, antiwear and self-lubricant properties represents an outstanding coating material to improve the tribological performance of bare metal-to-metal contacts. The DLC friction response is strictly related to the generation of a carbon-rich transfer layer on the sliding countersurfaces. This key process may benefit from the DLC surface functionalization with carbon nanomaterials, as attested by the recent observation of wearless sliding and ultra-low friction for nanorough model interfaces. In this study, we show by ball-on-disc tribometer that the tribological response of microrough steel-DLC contacts is considerably improved in dry atmosphere through DLC functionalization with graphene sheets (GSs) and nanodiamonds (NDs). The functionalization effectiveness is demonstrated exclusively with both allotropic forms, that synergically lower friction after a unique run-in period. We attribute the enhanced lubricity, with steady coefficient of friction <0.05 at 1 N load, to the formation of a transfer layer which incorporates GSs, NDs and nanoscroll structures self-assembled during sliding. High-resolution electron microscopy and Raman spectroscopy indicate that NDs, besides enabling the erosion of the highest interfacial micro-asperities, do assist the transfer layer development via GSs milling. Our findings contribute to the current quest for superlubricity in realistic tribocontacts meeting industrial standards.

Universality of hydroxyl radical generation in irradiated nanoenhancer suspensions: Vital role of concentration

Concentration plays an essential role in generating hydroxyl radicals in irradiated nanoenhancer suspensions. In this paper, we used coumarin-3-carboxylic acid as a hydroxyl radical-specific probe to investigate the hydroxyl radical production of different concentration nanodiamonds (NDs) and CeO2 NPs in phosphate-buffered saline under x-ray irradiation. NDs significantly enhanced hydroxyl radical production, and the maximum enhancement of hydroxyl radical production was observed at a concentration of 10 µg/ml, with an enhanced factor of 1.398 ± 0.262. CeO2 NPs can increase and scavenge hydroxyl radicals at different concentration ranges, with the lowest and highest enhanced factors of 0.623 ± 0.069 and 1.738 ± 0.264, respectively. We tested the hydrodynamic diameter at various concentrations to explore the concentration effect further. We found that with increasing concentration, there might be factors, such as hydroxyl radical recombination and nanoparticle agglomeration, that lead to changes in the enhancement factor. Based on the data from previous and present studies, the experimental results indicate that the concentration factor is essential for hydroxyl radical generation in nanoenhancer suspensions under ionizing radiation. We also provide possible mechanisms for enhancing hydroxyl radical production by nanoenhancers in water under ionizing radiation and the decrease in enhancement factor at high concentrations of nanoenhancers.

Additive manufacturing of AA5083/TiN-Diamond hybrid nanocomposite parts via additive friction stir deposition: Metallurgical structure, mechanical, tribological, and electrochemical properties

Nano-diamond (ND) is a special ultrafine reinforcement whose agglomeration properties and weak interfacial bonding limit its application in aluminum matrix composites. This study used the additive friction stir deposition (AFSD) technique to produce AA5083-H321/2.5 wt% nano TiN/ND additive manufacturing deposition hybrid composite parts (AMDCPs) and a non-composite part (AMDNCP) was also deposited for comparative analysis. The aim was to improve the microstructure and examine the effect of the deposition process parameters, which include 900, 1250, and 1600 rpm rod rotation speed and 5 and 12 mm/min feed rate. The AFSD process parameters were used to calculate the heat input. The consumable rod and AMD parts were evaluated for their macrostructure, microstructure, macro-hardness, tribological, and corrosion properties. The microstructural features were examined using an OM, XRD, and SEM equipped with an EDS. The worn and corrosion surface morphology was investigated using SEM, and hardness was also evaluated as contour maps. The results show that defect-free deposited multilayer AA5083-nano TiN/ND hybrid composite parts were successfully manufactured, and analysis revealed a lower D/H ratio, well-bonded layers, homogeneously distributed TiN/ND and fragmented IMC components, and equiaxed refined grain microstructures. The deposited composites via AFSD showed a lower corrosion rate, higher hardness, and wear resistance than the deposited AA5083 consumable rod and AMDNCP. The AMDP C900-12 demonstrates an optimized deposition process parameter (900 rpm, 12 mm/min) with superior properties, including an increase in hardness by 9.3%, a reduction in grain size by 54%, and a decrease in corrosion rate by 45.2% related to the AMDNC part.