Surface Of Nanodiamond Particles Research Articles

Characterization of Langmuir Monolayers for Nanodiamonds Surface‐Modified with 12‐Hydroxystearyl Chains and the Occurrence of Structural Colors

AbstractThe surfaces of nanodiamond particles are modified using natural castor oil‐derived 12‐hydroxystearic acid, which has thixotropic solvent properties. 12‐Hydroxystearyl chain‐modified nanodiamonds (12OHSt‐ND) are spread from a dispersion medium onto ultrapure water to afford Langmuir monolayers (a single‐particle layer) of 12OHSt‐ND exhibited a two‐dimensional phase transition from an expanded phase to a condensed phase. The surface morphology of the single‐particle layer shows a dispersed form of aggregated particles, while the layered regularity of the multilayers shows high periodicity. The surface hydrophobicity of the single‐particle layer of 12OHSt‐ND is more pronounced than that of the single‐particle layer of stearic acid‐modified nanodiamonds. The origin of the surface hydrophobicity of the single‐particle layer of 12OHSt‐ND is predicted to be the vertical conformation of the modified chains achieved via hydrogen bonding between the modified chains. In addition, the stepwise multilayers of 12OHSt‐ND exhibit various structural colors depending on the number of layers.

Tribological performance of nano-diamond composites-dispersed lubricants on commercial cylinder liner mating with CrN piston ring

AbstractThis work investigated the effect of nanodiamond (ND) additives on the tribological properties of CrN-coated piston ring mating with the chromium-plated and BP alloy iron cylinder liners, which is one of the key friction pairs in the internal combustion engines. To enhance the dispersion of the NDs in the base oil, the surface of ND particles was modified with polyaniline viain situpolymerization. The friction and wear as well as the scuffing characteristics of the friction pair lubricated with different contents of ND composite-added base oil were evaluated by using the reciprocating tribotests, which are close to the actual conditions. The wear surface morphologies and elements distribution were analyzed to explore the wear behaviors and the associated mechanisms of friction pairs under the lubrication incorporated with the ND composites. The results show that the ND additive is beneficial for the pair of Cr liner and CrN-coated piston ring in the friction and wear as well as scuffing properties, and the best concentration of ND additive is expected to be around 1 wt%. But for the BP liner, the developed nanocomposite has a negative impact. The friction force and the wear loss of the pair lubricated by the ND composite-added oil are even worse than that tested with the base lubricating oil.

Charges of Hydrogen Atoms in a Nanodiamond Modified with Proton-Donor Groups

Charges on hydrogen atoms of proton-donor groups (OH, COH, COOH, H) modifying the surface of nanodiamond particles have been simulated by DFT quantum chemical calculations. The highest charge has been found on the OH hydrogen atom.

Orthogonal Functionalization of Nanodiamond Particles after Laser Modification and Treatment with Aromatic Amine Derivatives.

A laser system with a wavelength of 1064 nm was used to generate sp2 carbon on the surfaces of nanodiamond particles (NDPs). The modified by microplasma NDPs were analysed using FT-IR and Raman spectroscopy. Raman spectra confirmed that graphitization had occurred on the surfaces of the NDPs. The extent of graphitization depended on the average power used in the laser treatment process. FT-IR analysis revealed that the presence of C=C bonds in all spectra of the laser-modified powder. The characteristic peaks for olefinic bonds were much more intense than in the case of untreated powder and grew in intensity as the average laser power increased. The olefinized nanodiamond powder was further functionalized using aromatic amines via in situ generated diazonium salts. It was also found that isokinetic mixtures of structurally diverse aromatic amines containing different functional groups (acid, amine) could be used to functionalize the surfaces of the laser-modified nanoparticles leading to an amphiphilic carbon nanomaterial. This enables one-step orthogonal functionalization and opens the possibility of selectively incorporating molecules with diverse biological activities on the surfaces of NDPs. Modified NDPs with amphiphilic properties resulting from the presence carboxyl and amine groups were used to incorporate simultaneously folic acid (FA-CONH-(CH2)5-COOH) and 5(6)-carboxyfluorescein (FL-CONH-(CH2)2-NH2) derivatives on the surface of material under biocompatible procedures.

Erratum to: “Mechanism of Functionalization of the Surfaces of Detonation Nanodiamonds: Mass-Spectrometric Investigation”

The comparison of the formation processes of volatile products at heating mixtures of detonation nanodiamonds with perfluorochemical alcohol and nanodiamonds subjected to directed chemical modification with perfluorochemical alcohol was made using the thermodesorption mass-spectrometry. A change of the destruction mechanism and increase of the thermostability of perfluorochemical alcohol by ~ 100°C as a result of a directional chemical modification was revealed, the most possible models of functionalization through hydrogen and covalent bonds of the hydroxyl group of fluorine radicals with carboxyl groups of surfaces of nanodiamond particles are suggested, the degrees of the functionalization and energy of the desorption activation of the products of the destruction functionalized molecules are assessed.

Nanodiamond enhances immune responses in mice against recombinant HA/H7N9 protein

BackgroundThe continuing spread of the newly emerged H7N9 virus among poultry in China, as well as the possibility of human-to-human transmission, has attracted numerous efforts to develop an effective vaccine against H7N9. The use of nanoparticles in vaccinology is inspired by the fact that most pathogens have a dimension within the nano-size range and therefore can be processed efficiently by the immune system, which leads to a potent immune response. Herein, we report a facile approach to increase antigen size to achieve not only fast but also effective responses against the recombinant HA/H7N9 protein via a simple conjugation of the protein onto the surface of nanodiamond particles.ResultsIn this study, trimeric Haemagglutinin (H7) that is transiently expressed in N. benthamiana was purified using affinity chromatography, and its trimeric state was revealed successfully by the cross-linking reaction. The trimeric H7 solution was subsequently mixed with a nanodiamond suspension in different ratios. The successful conjugation of the trimeric H7 onto the surface of nanodiamond particles was demonstrated by the changes in size and Zeta-potential of the particles before and after protein coating, Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and Western-blot analysis. Next, biofunction of the protein-nanodiamond conjugates was screened using a haemagglutination assay. A mixture containing 5 µg of trimeric H7 and 60 µg of nanodiamond corresponds to a ratio of 1:12 (w/w) of agglutinated chicken red blood cells at HA titer of 1024, which is 512-fold higher than the HA titer of free trimeric H7. After the 2nd and 3rd immunization in mice, ELISA and Western blot analyses demonstrated that the physical mixture of trimeric H7 protein and nanodiamond (1:12, w/w) elicited statistically significant stronger H7-specific-IgG response demonstrated by higher amounts of H7N9-specific IgG (over 15.4-fold with P < 0.05 after the second immunization).ConclusionsThese results indicated a potential effect inherent to nanodiamond towards modulating immune systems, which should be further evaluated and broadly applied in nanovaccine development.

Pore-Free Matrix with Cooperative Chelating of Hyperbranched Ligands for High-Performance Separation of Uranium.

A new strategy combining a pore-free matrix and cooperative chelating was proposed in the present paper in order to effectively avoid undesired nonselective physical adsorption and intraparticle diffusion caused by pores and voids in porous sorbents, and to greatly enhance uranium-chelating capability based on hyperbranched amidoxime ligands on the surface of nanodiamond particles. Thus, a pore-free, amidoxime-terminated hyperbranched nanodiamond (ND-AO) was designed and synthesized. The experimental results demonstrate that the strategy endows the as-synthesized ND-AO with the following expected features: (1) distinctively high uranium selectivity (SU = qe-U/qe-tol × 100%) from over 80% to nearly 100% over the whole weak acidity range (pH < 4.5); especially, the SU can reach up to unprecedented >91% at pH 4.5, more than 20% of selectivity increment over any analogous sorbent materials reported so far, with a uranium sorption capacity of 121 mg/g in simulated nuclear industry effluent samples containing 12 coexistent nuclide ions; (2) superfast equilibrium sorption time of <30 s; and (3) one of the highest distribution coefficients (Kd) of ∼3 × 106 mL/g for U(VI) as well as a fairly high sorption capacity of 212 mg/g at pH 4.5 in pure uranium solution. The strategy could also provide an optional approach for the design and fabrication of other new high-performance sorbing materials with prospective applications in selective separation of other interested metal ions.

Experimental thermal conductivity and viscosity of nanodiamond-based propylene glycol and water mixtures

Nanodiamond (ND) nanoparticles of primary particle size of 5–10nm can be produced in large quantity by using commercially available ultra-dispersed diamond (UDD) powders. The UDD powders contains large quantity of carbon impurities, which can be removed using strong acid treatment, dry salt and dry sucrose to make UDD powders into single ND particles. The formation of carboxyl (COOH) groups on the surface of ND particles was analyzed by FTIR spectrum. The X-ray powder diffraction (XRD), transmission electron microscope (TEM) and Raman spectra was also performed on acid treated ND particles. The propylene glycol/water mixtures at different weight ratios were used as base fluids for the preparation of stable ND nanofluids. The thermal conductivity and viscosity of ND nanofluids were estimated experimentally at different particle concentrations and temperatures. Based on the results, the thermal conductivity enhancements are 18.8%, 16.8% and 14.1% at 1.0vol.% of 20:80%, 40:60% and 60:40% PG/W based nanofluids. Similarly, the viscosity enhancements are 1.55-times, 1.50-times and 1.66-times for the same 1.0vol.% of 20:80%, 40:60% and 60:40% PG/W based nanofluids at a temperature of 60°C, respectively compared to their respective base fluids. New thermal conductivity and viscosity correlations have been developed based on the experimental data. Theoretical approach is used to identify the heat transfer benefits of the prepared propylene glycol/water based ND nanofluids in laminar and turbulent flow conditions using the thermal properties.

Science and engineering of nanodiamond particle surfaces for biological applications (Review).

Diamond has outstanding bulk properties such as super hardness, chemical inertness, biocompatibility, luminescence, to name just a few. In the nanoworld, in order to exploit these outstanding bulk properties, the surfaces of nanodiamond (ND) particles must be accordingly engineered for specific applications. Modification of functional groups on the ND's surface and the corresponding electrostatic properties determine their colloidal stability in solvents, formation of photonic crystals, controlled adsorption and release of cargo molecules, conjugation with biomolecules and polymers, and cellular uptake. The optical activity of the luminescent color centers in NDs depends on their proximity to the ND's surface and surface termination. In order to engineer the ND surface, a fundamental understanding of the specific structural features and sp(3)-sp(2) phase transformations on the surface of ND particles is required. In the case of ND particles produced by detonation of carbon containing explosives (detonation ND), it should also be taken into account that its structure depends on the synthesis parameters and subsequent processing. Thus, for development of a strategy of surface modification of detonation ND, it is imperative to know details of its production. In this review, the authors discuss ND particles structure, strategies for surface modification, electrokinetic properties of NDs in suspensions, and conclude with a brief overview of the relevant bioapplications.

Electrodeposition of Pt nanoparticles on undoped nanodiamond powder for methanol oxidation electrocatalysts

Abstract Undoped nanodiamond (ND) powder with average particle sizes of 5 and 100 nm were modified with platinum (Pt) nanoparticles by electrodeposition from 1.1 mM chloroplatinic acid solution. The structure and morphology of the composites were characterized by field emission-scanning electron microscopy and X-ray diffraction. The results showed that Pt nanoparticles were well-dispersed on the facet surfaces of ND particles. The electrooxidation of methanol on Pt-modified ND powders was investigated by cyclic voltammetry, which indicated its good electrocatalytic activity. Compared with 100 nm ND powder, the 5 nm ND powder modified with Pt nanoparticles exhibited better electrocatalytic activity.

Fabrication of Polystyrene-Encapsulated Nanodiamond via &lt;i&gt;In Situ&lt;/i&gt; Latex Polymerization and their Wettability Evaluation

Nanodiamonds coated with polystyrene were prepared by in-situ latex polymerization using azobisisobutylonitrile as initiator in alcohol-water solution. The products were characterized by transmission electron microscope, X-ray diffraction, thermo-gravimetric and differential thermal analysis and Fourier transformation infrared spectrum. A possible formation mechanism and the structure of products were proposed. The experimental evaluation of wettability performance showed that the hydrophobicity of nanodiamond have been enhanced with the wrapping of polystyrene films on the surface of nanodiamond particles.

Wet Chemistry Route to Hydrophobic Blue Fluorescent Nanodiamond

Hydrophobic blue fluorescent nanodiamond was synthesized by covalent linking of octadecylamine to the surface of nanodiamond particles. The material is easily dispersible in hydrophobic solvents, forming a transparent colloidal solution, and can be used in those applications where stable dispersions of nanodiamond in fuels, polymers or oils are required. Bright blue fluorescence of the octadecylamine-modified nanodiamond opens up new avenues for its use as a non-toxic quantum dot analogue for biomedical imaging of cellular membranes and other hydrophobic components of biological systems. Similar surface modification can be used for other carbon nanoparticles.

State of C-atoms on the modified nanodiamond surface

XPS, EEL, Auger and FTIR spectroscopies were used to testify the influence of chemical treatment upon the state of C-atoms in the core and on the surface of nanodiamond particles. The study was carried out with ND (JSC “Diamond Centre”). The different kinds of treatments were done ex-situ: with air (5 h) at 200 and 400 °C; with hydrogen (5 h) at 800, 850 and 900 °C; with fluorine (48 h) at 20 °C and 0.5 atm. Noticeable change was not found in the state of C-atoms both on the surface and up to 10 monolayers after these treatments. The concentration of F in the sample is equal to ∼ 9 at.%. The binding energy of the F 1s differs from the one in functional groups— –CF 2, –CF. Nevertheless FTIR spectra show bands that can be related to С–О, С–F bonds.

Nanophase of Water in Nano-Diamond Gel

The nanosized water phase has been discovered while studying differential scanning calorimetry (DSC) of the aqueous gel of nano-diamond particles (diameter ca. 5 nm). Two endothermic peaks were observed in the DSC traces of frozen gel upon warming; a broad peak appeared at 265 K before the melting of bulk water, which is attributed to the melting of nanophase water adsorbed onto the surface of nano-diamond particles. The events can be reproduced in exothermic fashion upon cooling the same sample. The mass of nanophase water per one nano-diamond particle and the melting enthalpy of nanophase water were derived from the DSC data. Similar nanophase water was observed earlier in gels prepared from an aqueous dispersion of C60 clusters with an average diameter of 68 nm, but the effect was not as distinct as with nano-diamond particles. These results demonstrate that DSC could be a versatile tool to study the stability of carbon nanoparticles in liquid media.

Chemical state of carbon atoms on the surface of nanodiamond particles

Auger electron spectroscopy study of the chemical state of carbon atoms on the surface of nanodiamond particles is performed. Auger spectra of nanodiamond particles indicate that carbon atoms in nanodiamond are in the same state as those in graphite, i.e., in the σ s 1 σ p 2 π1 state, but the π band is displaced 1 eV in energy below the Fermi level. The surface of nanodiamond particles is inert with respect to the ambient medium.