Search

To study the physicochemical (including adsorption) properties of nanodiamond, it is necessary to reproducibly obtain a carbon surface of an individual particle without metallic impurities of an unknown composition. Such a surface can be obtained through an additional procedure of the deep purification of a commercially available sample. This work is devoted to a study of the composition of non-combustible impurities of detonation diamond nanopowder. Using inductively coupled plasma mass spectrometry, iron and titanium are identified as the main metallic components of the non-combustible residue, the presence of Cr, Ni, Zr, As, and Sb is qualitatively established. The expected composition of the main molecular ions formed on the surface of the non-combustible residue under laser desorption/ionization mass spectrometry conditions is presented. Based on the results of the mass spectrometric analysis, a version of two-stage chemical treatment of detonation diamond nanopowder is proposed, which made it possible to reduce the mass fraction of non-combustible impurities during annealing in air from 2.0 to 0.1%. [ABSTRACT FROM AUTHOR]

The properties of graphene oxide–detonation nanodiamond composites obtained as a result of heterocoagulation of graphene oxide and hydrogenated detonation nanodiamonds in aqueous mixtures were studied. The resulting composites with different proportions of graphene oxide and detonation nanodiamond were subjected to drying and subsequent heat treatment in a vacuum, converting graphene oxide into graphene. The structure of the composites was studied using electron microscopy and Raman spectroscopy. The specific surface area and porosity of the obtained samples were studied by analyzing nitrogen adsorption isotherms. A model for the composite formation and a possible technology for producing a material based on it with different specific surface area values and pore structure are proposed. It is shown, that the largest possible specific surface area of two-component structures of the «DND/GO» type does not exceed 500 m2·g−1. It was also concluded that it is necessary to achieve a uniform distribution of detonation nanodiamond particles over the surface of graphene sheets. [ABSTRACT FROM AUTHOR]

Coagulation of polydisperse detonation nanodiamond (DND) hydrosol containing primary aggregates with a prevailing average size in a range of 20–200 nm has been studied experimentally and theoretically within the framework of the classical and extended DLVO theory as depending on the concentrations of an indifferent electrolyte (NaCl) and potential-determining ions (pH). It has been shown that the surface of DND particles is charged due to the ionization of ionogenic amphoteric hydroxyl and acidic carboxyl groups located on it. The isoelectric point of the detonation nanodiamond particles has been found to correspond to pH 7.5. It has been revealed that the main stabilizing factor of the DND hydrosol is electrostatic. It has been shown that the stability and coagulation of the sol can be described within the framework of the extended DLVO theory using the effective Hamaker constant for primary porous aggregates and taking into account the initial polydispersity of the DND particles. [ABSTRACT FROM AUTHOR]

Fluorine-doped detonation nanodiamond (DND) powders are considered as a new class of neutron reflectors and can significantly improve the performance of very cold and ultracold neutron sources, which in turn will lead to new types of experiments at a qualitative level. These improvements are achieved due to such properties of DND as high diffusion and quasi-mirror reflection. The high reflectivity improves the neutron delivery efficiency and, consequently, the neutron fluxes at neutron facilities. On this basis, fluorinated DNDs are considered as a potential neutron reflector material for the designed very cold and ultracold neutron source at the WWR-K reactor. However, to date, experimental data on the behaviour of fluorinated DND in the neutron field are insufficient, and therefore, in order to study the radiation resistance of DND at the WWR-K reactor, work has been started on their irradiation and further study. For this purpose, an optimal irradiation capsule design was developed and comprehensive calculations were performed to justify the conditions and limits of reactor irradiation. This paper describes the irradiated samples and reactor experiment, the methodology and conditions for irradiating the samples, and the results of their initial characterisation after irradiation. [ABSTRACT FROM AUTHOR]

Aqueous suspensions (colloids) containing detonation nano-diamond (DND) feature in most applications of DND and are an indispensable stage of its production; therefore, the interaction of DND with water is actively studied. However, insufficient attention has been paid to the unique physico-chemical and biological properties of transparent colloids with low DND content (≤0.1%), which are the subject of this review. Thus, such colloids possess giant dielectric permittivity which shows peculiar temperature dependence, as well as quasi-periodic fluctuations during slow evaporation or dilution. In these colloids, DND interacts with water and air to form cottonwool-like fibers comprising living micro-organisms (fungi and bacteria) and DND particles, with elevated nitrogen content due to fixation of atmospheric N2. Prolonged contact between these solutions and air lead to the formation of ammonium nitrate, sometimes forming macroscopic crystals. The latter was also formed during prolonged oxidation of fungi in aqueous DND colloids. The possible mechanism of N2 fixation is discussed, which can be attributable to the high reactivity of DND. [ABSTRACT FROM AUTHOR]

We have studied Cu–Zn and Cu–Ni containing catalysts on carbon supports based on IR-pyrolyzed chitosan and detonation nanodiamond (DND) and assessed their activity for the methanol steam reforming process. All of the catalysts have demonstrated rather high activity for this process and good stability over 30 h of continuous operation. The DND-based catalysts have been shown to have better performance, which seems to be due to their larger surface area and the nature of the functional groups on their surface. The activity of the bimetallic catalysts and the nature of the supports have been shown to be interrelated. [ABSTRACT FROM AUTHOR]

Carbon-fiber-reinforced plastics are composite materials with record-high specific strength, which depends on the efficiency of stress redistribution between the reinforcing fibers by the polymer matrix. The problem is the accurate assessment of adhesion in the carbon fiber–polymer matrix system since it affects the overall strength of the composite. This paper provides a novel electrochemical method for determining adhesion by estimating the critical length of carbon fibers that protrude above the fracture surface of the fiber-reinforced composite using their electrical conductivity and insulating properties of the polymer matrix. The method has been successfully applied to evaluate adhesion in carbon plastics having an epoxy matrix filled with nanoparticles of different anisometry: carbon nanotubes, organomodified montmorillonite, or detonation nanodiamonds. In addition to adhesion measurements, the effect of nanoparticles on the viscosity of epoxy binder, its impregnation efficiency of carbon fibers, curing, glass transition, and tensile strength of fiber-reinforced composites was estimated. Nanodiamonds at a mass fraction of 0.1% proved to be the most effective for improving the quality of epoxy carbon plastics, increasing fiber–matrix adhesion by 2.5 times, tensile strength by 17%, and not decreasing the glass transition temperature. [ABSTRACT FROM AUTHOR]

We present the results of study the structure and composition of microcrystalline diamonds obtained by high-pressure high temperature sintering of detonation nanodiamond particles. Using optical detected magnetic resonance method, photoluminescence spectroscopy and Raman spectroscopy we found sintering of detonation nanodiamond significantly differ from initial detonation nanodiamonds and can be compared to high quality diamonds. Monocrystals of diamonds obtained by the method of oriented attachment have dimensions of up to tens of microns, possess the habitus of high-quality diamonds, and do not contain metal catalysts in the lattice structure. In those crystals, the presence of optically active nitrogen impurities in the crystal lattice is observed. In particular, there is a bright nitrogen-vacancy defects. They are characterized by optical detected magnetic resonance method, which shows that spin properties of the obtained single crystals correspond to high-quality natural diamonds and surpass synthetic diamonds obtained from graphite in the presence of metal catalysts, followed by irradiation and annealing to obtain nitrogen-vacancy defects optical defects in the diamond lattice. The presence of nitrogen vacancy defects and the high-quality of the crystal structure of sintering of detonation nanodiamond allows us to consider them as potential candidates in quantum magnetometry. For this purpose, the possibility of a simple way to improve the AFM probe by fixing a microcrystalline sintering of detonation nanodiamond particle on its tip is demonstrated. [ABSTRACT FROM AUTHOR]

Supercapacitors play a major role in the field of energy storage. However, the production of highly efficient and durable supercapacitors using sustainable materials remains a challenge. Herein, we report on a green approach for the production of thin film binder electrodes for electric double layer capacitors (EDLCs) based on onion-like carbon. The active material obtained by high temperature treated detonation nanodiamond offers a specific surface area of 527 m2 g−1 after an additional activation step. The key to facilitate the electrode manufacturing for this active material was the introduction of an agglomeration step of the carbon nano-onions which qualified them for the usage of plant-based carboxymethyl cellulose (CMC) as binder. The new types of electrodes were successfully tested in a supercapacitor full cell setup and benchmarked against electrodes relying on conventional fluorinated polymer (PVDF) as binder. The green electrodes provide about 22% higher specific capacitance of 56 F g−1 at a similar durability over more than 5000 cycles, combining sustainable production with excellent performance. [Display omitted] [ABSTRACT FROM AUTHOR]

In the present paper, a new approach for detonation nanodiamond (DND) deagglomeration is proposed. DND agglomerates of the size from 20 to 200 nm have been exposed to wet sonication assisted oxidative treatment with ozone under UV irradiation (Advanced Oxidation Process). Subsequent sonication and centrifugation gave a stable hydrosol of individual DND particles with negative zeta potential of −65 mV. The yield of the desired 4–5 nm fraction reached 33 wt%. Powder X-Ray Diffraction study showed no signs of DND crystalline core degradation, while the surface of particles was enriched significantly with carboxyl functional groups according to the data of Diffuse Reflectance Infrared Fourier Transform Spectroscopy, that gave boost to the stability of DND hydrosol. The approach provides relatively high yield of deagglomerated detonation nanodiamond without impact of high temperatures on the DND particles. It also allows avoiding gas phase processes sticking to wet-chemistry that could be useful for process scalability. [ABSTRACT FROM AUTHOR]

Two versions of powders of a charge of detonation nanodiamond doped with 0.96 and 0.73 wt % boron are obtained by explosion using a mixture of TNT with hexogen (TG) (50/50) or tetryl, respectively. Their morphology, texture, and mesostructure are investigated by scanning electron microscopy, small-angle neutron scattering, and low-temperature nitrogen adsorption. A significant effect of the explosion's precursor on the structure and morphology of the obtained carbon nanopowders is found. [ABSTRACT FROM AUTHOR]

Nanodiamonds combine unique mechanical, thermodynamic and optical properties of diamond with the peculiarities of colloidal dimensions and wide possibilities of chemical modification of their surface. Of particular practical interest is the presence of a branched porous structure inside detonation nanodiamond agglutinates in powders. Application of moderate (up to 1.5 GPa) static pressures allowed us to separate the contributions to small-angle scattering from micro- and nanosized pores. In continuation of the previous studies, the given research shows the possibilities of controlling the fractal structure of the porous system at the nanoscale by applying static pressure. Thus, the partial pore recombination in the pressure range covered leads to the formation of linear pores, in contrast to the branched system characteristic for the initial industrial samples. This modification can have a wide practical impact associated with the loading of anisotropic additives. [ABSTRACT FROM AUTHOR]

[Display omitted] Detonation nanodiamonds with a particle size of 5 nm and a carboxylated surface are easily modified by doubly charged copper ions to form copper chelate complexes. The concentration of copper complexes in a dry powder of such nanodiamonds is well monitored by the method of electron paramagnetic resonance, both by the signal width of intrinsic paramagnetic centers in nanodiamonds and by the signal shape for the surface Cu2+ ions themselves, including the set of hyperfine splitting lines for the parallel component and the line with an unresolved hyperfine structure for the perpendicular component. [ABSTRACT FROM AUTHOR]

The process of anodic oxidation of aluminum and its alloys in the presence of a diamond blend (DB) obtained by detonation of tetryl (N-methyl-2,4,6-trinitrophenylnitramine) is studied. It is shown that the use of a DB is highly promising for the preparation of a corrosion-resistant wearproof high-hardness anodic oxidation coating, the parameters of which are 1.6 times higher than those of the coatings obtained by the standard process in a standard electrolyte. The concentration of the DB in the sulfuric acid electrolyte is 2–3 g/L. [ABSTRACT FROM AUTHOR]

Purpose: Testing the potential use of saline suspension of polyvinylpyrrolidone (PVP)‐coated gadolinium(Gd)‐grafted detonation nanodiamonds (DND) as a novel contrast agent in MRI. Methods: Stable saline suspensions of highly purified de‐agglomerated Gd‐grafted DND particles coated by a PVP protective shell were prepared. T1 and T2 proton relaxivities of the suspensions with varying gadolinium concentration were measured at 8 Tesla. A series of ex vivo (phantom) and in vivo dynamic scans were obtained in 3 Tesla MRI using PVP‐coated Gd‐grafted DND and gadoterate meglumin in equal concentrations of gadolinium, and then T1‐weighted hyperintensity was compared. Results: The proton relaxivities of PVP‐coated Gd‐grafted DND were found to be r1 = 15.9 ± 0.8 s−1 mM−1 and r2 = 262 ± 15 s−1 mM−1, respectively, which are somewhat less than those for uncoated Gd‐grafted DND but still high enough. Ex vivo MRI evaluation of PVP‐coated Gd‐grafted DND results with a dose‐dependent T1‐weighted hyperintensity with a significant advantage over the same for gadoterate meglumin. The same was found when the 2 contrast agents were tested in vivo. Conclusion: The novel MRI contrast agent — saline suspensions of PVP‐coated Gd‐grafted DND — provides significantly higher signal intensities than the common tracer gadoterate meglumin, therefore increasing its potential for a safer use in clinics. [ABSTRACT FROM AUTHOR]

There were illustrated the main questions of development of new generation drug delivery systems as hybrid nanomaterials as follows: selection of nanocarrier, its standardization and the methods of immobilization of biologically active and medicinal substances. The basic organs of distribution and accumulation of advanced carbon nanocarrier - detonation nanodiamond were identified. It was shown that antihypoxic effect of the nanodiamond-glycine conjugate increased in comparison with a native Glycine and Mexidolum® as reference drugs.

[Display omitted] Niobium carbide composites were obtained by sintering niobium powder and detonation nanodiamond at high pressure (7 GPa) and high temperature (∼1990 °C) for several tens of seconds. The resulting composites demonstrate a set of distinct reflections from the NbC phase in the X-ray diffraction pattern and exhibit superconducting properties at temperatures below 11.4 K. [ABSTRACT FROM AUTHOR]

Detonation nanodiamonds (DND), their properties and deaggregation remain an active field of research. Here we innovated the salt-assisted ultrasonic deaggregation (SAUD) by employing NaHCO 3 (a milling agent with relatively low solubility) followed by dialysis (a purification step) and processed two DND and one laser-synthesized (LND) commercial powders. The obtained ND colloids were separated to single-digit supernatant with the yield of 57–65% and sediment fractions by centrifugation and analyzed separately. By thermal analysis we evidenced chemical sensitization of the SAUD-processed DNDs manifested by significantly lower combustion temperatures. By correlation of spectroscopic, microscopic, and thermal analysis techniques we revealed a size and shape inhomogeneity of primary DND particles, also affecting strength of aggregation. By elemental analysis of the fractions we also show that nitrogen content is systematically higher in the smaller primary DND particles. Those features are inherent to all the three ND samples. The provided analyses highlight the need for better understanding of relations between detonation synthesis parameters and properties of the synthesized DNDs in terms of DND primary particle size, aggregation and nitrogen incorporation. Image 1 • Size, shape and nitrogen inhomogeneity in detonation nanodiamond revealed by salt-assisted ultrasonic deaggregation (SAUD). • Smaller primary DND particles (4-5 nm) have higher nitrogen content, are less faceted, and are released by SAUD. • Larger primary DND particles (> 10 nm) have lower nitrogen content, are well faceted and, remain aggregated after SAUD. • Facets-driven electrostatic interactions and the liquid-phase sintering are both involved during DND synthesis. • The results evidence a compositional and kinetic inhomogeneity in the reaction zone during detonation synthesis. [ABSTRACT FROM AUTHOR]

The process of detonation synthesis of nanodiamonds from ternary systems was developed with conversion tetryl as their main component. The dependence of the yield of detonation nanodiamonds and their content in the diamond blend on the tetryl content in the ternary composition was shown as well as that of the yield of detonation nanodiamonds on the oxygen balance of the blend. The conditions and composition of the explosive were found to determine the maximum yield of detonation nanodiamonds, 8.2 wt %, based on which it is possible to develop a more economical and efficient industrial technology for the production of detonation nanodiamonds: the use of explosive compositions containing 50 wt % or more conversion tetryl, respectively, a decrease in the content of expensive and scarce RDX; high content of nanodiamond in the diamond blend, which reduces the cost of chemical cleaning; the possibility of a simple selection of the required oxygen balance of the explosive composition. [ABSTRACT FROM AUTHOR]

Specific features of the morphological and structural characteristics of nanopowder particles fabricated by grinding bulk natural diamond and by detonation synthesis are investigated. It is shown by high-resolution transmission electron microscopy, scanning electron microscopy, and low-angle X-ray scattering that, in contrast with the detonation synthesis nanopowder, which consists of similar in size and isometrically primary particles, natural diamond particles fabricated by grinding have a broader spread in regards to size and a preferentially platelet form. It is established by the X-ray structural phase analysis and Raman spectroscopy used in addition to above-listed methods that the structure of particles of nanodiamond formed from natural diamond is similar to the structure of detonation-synthesis nanodiamond. Each particle of natural nanopowder, similarly to detonation-synthesis nanodiamond, consists of a diamond core having a crystal lattice of the cubic crystal system and a shell containing mainly nondiamond forms of carbon with sp2 hybridization with a complex structure. The data on the evaluation of the average particle size of nanopowders of natural diamond and detonation synthesis by three methods, including BET, show results that satisfactorily agree with each other. Herewith, an average particle size of natural powder nanoparticles is close to 24 nm, while that of detonation-synthesis nanodiamonds of the UDA-S-GO brand produced by FRPC Altai is close to 5.6 nm. An insignificant increase in interatomic distances in diamond nanocrystals is revealed when compared with the bulk diamond crystal. The investigation and analysis of numerous images of natural diamond nanocrystals and detonation synthesis nanocrystals formed by high-resolution transmission electron microscopy show that the dislocations and point defects are most often defects in nanodiamonds. [ABSTRACT FROM AUTHOR]

The paper describes the data on unusual rheological properties of detonation nanodiamonds (DND) hydrosols and presents the fractal model explaining such behavior. The hydrosols of DND with particles size of 4–5 nm and concentration range of 1.1–7.3 wt% with negative (ζ < 0) and positive (ζ > 0) electrokinetic potentials have been studied by rotational viscometry, small-angle X-ray scattering, nuclear magnetic resonance and Cryo Electron Tomography. Remarkable hysteresis of viscosity and thixotropic effect demonstrate the sol-gel transition at very low concentrations of the DND: 4–5 wt% for ζ > 0 and 5–6 wt% for ζ < 0. The transition is accompanied by increase of loss (viscosity) modulus by two orders of magnitude and the storage (elasticity) modulus started to be detected also. The experimental results have been explained in the frame of percolation theory based on the network formation due to faceted DND particles interactions. Image 1 [ABSTRACT FROM AUTHOR]

Carbon particulates generated during detonation depend upon high explosive type, composition, and detonation conditions. Although explosive composition greatly affects particulates, the focus of this work is on how detonation geometries that induce much higher temperatures and pressures in the high explosive lead to differing particulate morphologies. In this study, two geometries were used: Detonations were initiated in Composition B cylinders at one end in conventional detonations and initiated at both ends to produce colliding detonations. Each of these detonations was observed on the sub‐μs timescale using fast radiography capturing images of the front moving through the cylinder, and colliding detonation fronts in real‐time. These imaging experiments were complemented with time‐resolved small‐angle x‐ray scattering (SAXS) experiments that were able to observe and determine the varying condensed carbon morphologies at different locations and times in each detonation. The detonations could be timed in such a way that the spatial and temporal dependence of the carbon morphology could be superimposed onto radiography images collected at the same point in time. The complementary approach is able to show that the carbon condensates are much larger when formed in the elevated temperature and pressure conditions near the location of colliding detonation fronts. Thermochemical modeling suggests that these larger particulates form either in the diamond phase or on the liquidus line of the carbon phase diagram. The increase in size observed by SAXS may correlate well with the increased residence time deeply in the diamond phase. These particulates can be described as nano‐sized phases with some surface texture or otherwise near‐surface intra‐particle heterogeneity. [ABSTRACT FROM AUTHOR]

IR spectroscopy of fluorinated detonation nanodiamond demonstrates that an intense absorption band at ∼1344 cm–1 and two smaller ones at ∼1324 and ∼1258 cm–1 form the extended low wave-number wing of the observed consolidated spectrum in the range of 1100–1400 cm–1. The intrinsic infrared absorption of CF x bonding at the nanodiamond surface sites has been determined after subtraction of the contribution from remaining C–O and C–O–C groups inside the aggregates of tightly-bonded fundamental nanodiamond particles, which had not been subjected to fluorine attack and to their replacement by fluorine containing groups. [ABSTRACT FROM AUTHOR]

The development of different methods for tuning surface properties is currently of great interest. The presented work is devoted to the use of modified nanodiamonds to control the wetting and biological fouling of polymers using optical sensors as an example. We have shown that, depending on the type of modification and the amount of nanodiamonds, the surface of the same fluorinated polymer can have both bactericidal properties and, on the contrary, good adhesion to the biomaterial. The precise control of wetting and biofouling properties of the surface was achieved by the optimization of the modified nanodiamonds thermal anchoring conditions. In vitro and in vivo tests have shown that the fixation of amine functional groups leads to inhibition of biological activity, while the presence of a large number of polar groups of mixed composition (amide and acid chloride) promotes adhesion of the biomaterial and allows one to create a biosensor on-site. A comprehensive study made it possible to establish that in the first 5 days the observed biosensor response is provided by cells adhered to the surface due to the cell wall interaction. On the 7th day, the cells are fixed by means of the polysaccharide matrix, which provides much better retention on the surface and a noticeably greater response to substrate injections. Nevertheless, it is important to note that even 1.5 h of incubation is sufficient for the formation of the reliable bioreceptor on the surface with the modified nanodiamonds. The approach demonstrated in this work makes it possible to easily and quickly isolate the microbiome on the surface of the sensor and perform the necessary studies of its substrate specificity or resistance to toxic effects.

A technology to improve the tribological and mechanical surface properties of iron alloys is developed based on the electroless nickel plating. The technology combines sol-gel and electroless deposition technique. Novel nanocomposite coatings are obtained consisting of Nickel-phosphorus-nanodiamond (Ni-P-ND). The ND sol is added directly to the electroless Ni-P solution. A suitable surfactant is added to achieve well-dispersed ND particles in the electroless solution to facilitate their embodiment and equal distribution in the coating. Substrates of steel 17CrNiMo6 and spheroidal graphite cast irons are used for the manufacture of the iron alloys specimens. The surface morphology and microstructure observation performed by scanning electron microscopy (SEM) and optical metallography confirms the influence of ND particles on the coating structure. The structural phase investigation by X Ray analysis indicates a transformation of the amorphous phase to a crystalline one such as Ni, Ni3P after coatings' heat treatment. The microhardness investigation by Knoop Method and wear resistance measurement in accordance with the Polish Standard PN-83/H-04302 of Ni-P and Ni-P-ND composite coatings are evaluated and compared with each other. The increase in the value of hardness and wear resistance of Ni-P composite coatings in the presence of ND particles and after heat treatment is obtained.

Nanodiamonds (ND) hold great potential for diverse applications due to their biocompatibility, non-toxicity, and versatile functionalization. Direct visualization of ND by means of non-invasive imaging techniques will open new venues for labeling and tracking, offering unprecedented and unambiguous detection of labeled cells or nanodiamond-based drug carrier systems. The structural defects in diamonds, such as vacancies, can have paramagnetic properties and potentially act as contrast agents in magnetic resonance imaging (MRI). The smallest nanoscale diamond particles, detonation ND, are reported to effectively reduce longitudinal relaxation time T 1 and provide signal enhancement in MRI. Using in vivo, chicken embryos, direct visualization of ND is demonstrated as a bright signal with high contrast to noise ratio. At 24 h following intravascular application marked signal enhancement is noticed in the liver and the kidneys, suggesting uptake by the phagocytic cells of the reticuloendothelial system (RES), and in vivo labeling of these cells. This is confirmed by visualization of nanodiamond-labeled macrophages as positive (bright) signal, in vitro. Macrophage cell labeling is not associated with significant increase in pro-inflammatory cytokines or marked cytotoxicity. These results indicate nanodiamond as a novel gadolinium-free contrast-enhancing agent with potential for cell labeling and tracking and over periods of time., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

DLC films are used in many applications, and nanoparticles are being used as dopant materials in a large number of films. In this investigation, DLC films doped with nanodiamond were deposited on Ti6Al4V substrates. Detonation nanodiamond (DND) was stirred in hexane with a sonicator at 750 W to obtain a suspension, which was introduced by an evaporation process into a PECVD reactor to produce DLC films continuously doped with nanoparticles. An amorphous silicon interlayer was used before depositing the DLC on the Ti6Al4V substrate. Raman spectroscopy results showed films with hydrogen contents around 22%. A scratch test on the Ti6Al4V alloy showed critical loads close to 19 N, and corrosion resistance measured via potentiodynamic polarization was improved with doped DLC over that of the bare substrate. An antibacterial test was carried out with Gram-negative Escherichia coli , showing antibacterial activity close to 95% 6 h after direct contact with the film. This result suggested that DLC is an excellent material for biomedical purposes. After 18 h of direct contact with the doped DLC film, antibacterial activity close to 25% was observed, which suggested that nanodiamonds are able to maintain their antibacterial properties and produce damage to E. coli cells. • DLC films were obtained with nanodiamond suspensions continuously by PECVD. • Antibacterial properties of DLC with nanodiamond were close to 100%. • Disruption cell wall on E. coli with DLC film with nanodiamond was noticed. • DLC coatings doped with nanodiamond offer new applications in many medical areas. [ABSTRACT FROM AUTHOR]

• Different nano-fillers: detonation and non-detonation diamond and alumina were added to polyacrylic. • Addition of the nano-particles to polyacrylic is beneficial to its tribological properties. • All samples showed higher scratch resistance than the Blank sample. • Level of strengthening depends on the type, content and surface modification of nano-particles. • Surface modifications used, especially heat treatment, greatly affected the strengthening of DNDs. Hard ceramic particles were frequently added to polymers to improve their mechanical properties, e.g. scratch resistance. In recent years, however, some members of carbon nano-family such as carbon nanotubes and nanodiamonds were also widely used as reinforcements in polymeric matrices. In the present research, three different fillers including nano-alumina (NA), detonation (DND) and non-detonation (NDND) nanodiamonds were added to polyacrylic base automotive clear coats to improve the performance of the coating. Both nanodiamond types were surface functionalized to improve their dispersion and hence strengthening capacity. Several laboratory and industrial tests were performed on the coatings to study the mechanical behavior and resistance of the coatings to chemical reagents. The results showed that addition of these particles can strongly increase the scratch resistance of the coating while the other aspects of the coating was not deteriorated. In addition, the results proved the great potential of surface functionalization of DNDs over NDNDs on the performance of the coatings. The coating containing as-received DNDs and NDNDs showed scratch resistance lower than those containing NA however. However, the heat treated DNDs, unlike the heat treated NDNDs introduced a better scratch resistance in the coatings, considerably higher than the NA containing coatings. [ABSTRACT FROM AUTHOR]

The published and the authors' own data on the methods of chlorination of the surface of diamond micropowders are critically assessed. The features of different methods of chlorination of detonation nanodiamond (DND) are compared; the optimum process conditions are revealed. The method of gas-phase chlorination with molecular chlorine at elevated temperatures is preferable when using DND in biomedical applications; this method also helps lower the concentration of metal impurities. The use of thionyl chloride and sulfuryl chloride results in the contamination of DND-Cl samples with sulfur. It is shown that the DND-Cl samples have satisfactory hydrolytic stability. [ABSTRACT FROM AUTHOR]

Detonation nanodiamonds are gaining considerable research interest due to their superior hardness, excellent mechanical properties, large surface area and small size. Surface functionality of polymeric, fibrous materials and nanocomposites can be significantly improved by application of nanodiamonds. Although there has been some research on nanodiamonds in polymeric materials and composites available, research on fibrous materials, such as textiles, is limited. We investigated potential improvement in the properties of cotton materials after application of nanodiamonds. Nanodiamonds were applied to cotton fabric using a sustainable dip-coating laboratory technique, which was then characterized for improved functionality in such properties as strength, elongation, thermal stability and surface energy. It was observed that a surface coating of nanodiamonds enhanced the tensile strength of the cotton by 79%, without compromising the flexibility of the substrate significantly, due to the exceptional mechanical properties of the nanodiamond particles and strong bonding between fibers and yarns within the fabric. High thermal conductivity of the nanodiamonds resulted in increased thermal stability and a higher degradation temperature in the coated substrate, when compared with the uncoated cotton fabric. Scanning electron microscopy images indicated that the coated cotton fabric displayed a coarser surface than the uncoated fabric. Coated fabric also absorbed more energy than uncoated fabric during repeated deformation in abrasion testing, due to presence of nanodiamond which resulted in imporvement of abrasion resistance. [ABSTRACT FROM AUTHOR]

Adding phosphorus-modified detonation nanodiamonds to a standard electrolyte solution for electrochemical nickel plating raises the coating microhardness up to 660 kg/mm2, wear resistance by a factor of 8, and corrosion resistance up to 70-fold. [ABSTRACT FROM AUTHOR]

Fluorescent nanodiamonds (FNDs) are a new class of carbon nanomaterials that offer great promise for biological applications such as cell labeling, imaging, and sensing due to their exceptional optical properties and biocompatibility. Implementation of these applications requires reliable and precise surface functionalization. Although diamonds are generally considered inert, they typically possess diverse surface groups that permit a range of different functionalization strategies. This review provides an overview of nanodiamond surface functionalization methods including homogeneous surface termination approaches (hydrogenation, halogenation, amination, oxidation, and reduction), in addition to covalent and non-covalent surface modification with different functional moieties. Furthermore, the subsequent coupling of biomolecules onto functionalized nanodiamonds is reviewed. Finally, biomedical applications of nanodiamonds are discussed in the context of functionalization.

[Display omitted] Detonation nanodiamonds of 5 nm size with the surface terminated by carboxyl and/or hydroxyl groups, which act as radical scavengers, represent promising nanofillers for polymer composites. Irradiation of the nanodiamonds with 137Cs γ-rays does not produce long living paramagnetic species both inside the crystalline core and in the outer molecular shell. The reason is rapid interaction of the radiation-induced surface radicals with physisorbed water, molecular oxygen and oxidizing products of their radiolysis. [ABSTRACT FROM AUTHOR]

Hydrogenated detonation nanodiamonds are of great interest for emerging applications in areas from biology and medicine to lubrication. Here, we compare the two main hydrogenation techniques—annealing in hydrogen and plasma-assisted hydrogenation—for the creation of detonation nanodiamonds with a hydrogen terminated surface from the same starting material. Synchrotron-based soft X-ray spectroscopy, infrared absorption spectroscopy, and electron energy loss spectroscopy were employed to quantify diamond and non-diamond carbon contents and determine the surface chemistries of all samples. Dynamic light scattering was used to study the particles’ colloidal properties in water. For the first time, steady-state and time-resolved fluorescence spectroscopy analysis at temperatures from room temperature down to 10 K was performed to investigate the particles’ fluorescence properties. Our results show that both hydrogenation techniques produce hydrogenated detonation nanodiamonds with overall similar physico-chemical and fluorescence properties.

Gadolinium ions (Gd3+) can be fixed on the surface of 5-nm detonation nanodiamonds with terminal carboxyl and/or hydroxyl surface groups. Magnetization curves measured below the temperature of liquid helium at normal pressure give the amount of Gd3+ ions of about 18 per a 5-nm nanodiamond particle. The corresponding 2D surface density of ions is smaller than that obtained by density functional theory for a single gadolinium atom fixed on the surface of (111) diamond slab with 36 surface carbon sites with up-standing s-bonds by a factor of 2. [ABSTRACT FROM AUTHOR]

A simple method of stabilization of detonation nanodiamonds in isotonic aqueous-saline media was found, being a solution of an actual task for biomedical applications. The stable colloid of detonation nanodiamond particles with negative ζ-potential in isotonic medium can be produced by complexes formation with poly(vinylpyrrolidone). The mean size of the complexes is 30–35 nm. The stability conditions of the complexes were defined and their structure was determined by small-angle neutron scattering. The obtained hydrosols of nanodiamond particles are stable in physiological medium and can be used in biological researches and in medicine as drug carriers. [ABSTRACT FROM AUTHOR]

A ratio between the predicted and actual yields of condensed carbon in post-detonation processes of nanodiamond synthesis has been studied. These values are shown to closely coincide when optimal synthesis conditions are ensured. The yields of condensed carbon and detonation nanodiamonds in the industrial synthesis are 12.0 wt % and 8.16 wt %, respectively; the DND concentration in DS is up to 68 wt %. [ABSTRACT FROM AUTHOR]

Hypothesis Finding an efficient dispersant for obtaining a good dispersion of 5-nm detonation nanodiamond (DND) is always a challenge. Two newly designed diblock copolymers, both poly(ammonium methacrylate)- block -poly(2-phenoxyethyl acrylate) (PMA- b -PBEA) but with different molar ratios of PMA to PBEA, were proposed to be efficient dispersants in stabilizing the concentrated aqueous suspensions of DND. Experiments The dispersion efficiency of dispersants for DND in aqueous suspensions was studied by the measurements of particle size, sedimentation property, and rheological behavior. The interactions between the added dispersants and DND were identified by the zeta potential and adsorption analyses. Calculations based on Derjaguin-Landau-Verwey-Overbeek (DLVO) theory were conducted for clarifying the dominant parameters relating to the dispersion efficiency of dispersants. Findings Compared with the commercially popular dispersant ammonium polyacrylate, these two diblock dispersants exhibited superior efficiency in the stabilization of DND suspensions. Using the diblock copolymers as dispersants, good dispersion stability in a DND suspension with an extremely high solid content of 30 wt% was achieved. According to experimental analyses and based on DLVO calculations, a low number of accompanied counter-ions, high adsorption capability, and thick PMA- b -PBEA adsorption layer are the main reasons for the extremely high dispersion efficiency of the two new dispersants. [ABSTRACT FROM AUTHOR]

Specific properties of PTFE composites filled with ultradisperse detonation diamonds (UDDs) with different surface chemistries are studied. It is found for the first time that filler in the form of UDDs affects not only the rate of PTFE thermal decomposition in vacuum pyrolysis, but also the chemical composition of the products of degradation. The wear resistance of UDD/PTFE composites is shown to depend strongly on the UDD surface chemistry. The presence of UDDs in a PTFE composite is found to result in perfluorocarbon telomeres, released as a readily condensable fraction upon composite pyrolysis. The chemical interaction between PTFE and UDDs, characterized by an increase in the rate of gas evolution and a change in the desorbed gas’s composition, is found to occur at temperature as low as 380°C. It is shown that the intensity of this interaction depends on the concentration of oxygen-containing surface groups, the efficiency of UDDs in terms of the composite’s wear resistance being reduced due to the presence of these groups. Based on the experimental data, a conclusion is reached about the chemical interaction between UDDs and a PTFE matrix, its dependence on the nanodiamond surface chemistry, and its effect on a composite’s tribology. [ABSTRACT FROM AUTHOR]

We have recently shown that the sol-gel transition occurs in hydrosol of detonation nanodiamond (DND) particles with size of 4–5 nm. Here we study properties of the hydrosol. Namely, we study the dependence of dynamic viscosity and shear stress on DND concentrations. Dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) were used for characterization of the hydrosol structure. Deagglomeration of diamond nanoparticles in preparation of the hydrosol was carrying out without mechanical milling. In contrast with previous studies viscosity was measured by rotational viscometer. The observed effects can be explained by the model, that assumes existence of particle chains connected to each other by electrostatic interaction. Moreover, the potential of this interaction is non-spherically symmetric. Such chains of DND particles are present in hydrosols even at the concentration of about 1 wt%. [ABSTRACT FROM AUTHOR]