Positive zeta potential of nanodiamonds

In this paper, the origin of positive zeta potential exhibited by nanodiamond particles is explained. Positive zeta potentials in nano-structured carbons can be explained by the presence of graphitic planes at the surface, which leave oxygen-free Lewis sites and so promotes the suppression of acidic functional groups. Electron Microscopy and Raman Spectroscopy have been used to show that positive zeta potential of nanodiamond is only exhibited in the presence of sp2 carbon at the surface

Facile amine termination of nanodiamond particles and their surface reaction dynamics

Nanodiamond synthesized by the detonation method is a composite of sp3/sp2 carbon structures; amorphous and disordered-sp2 carbons populate the surface of a sp3 diamond core lattice. Because of the production process, various elemental impurities such as N, O, H, and so forth are inherent in interstitial sites or the surface carbon (sp2/amorphous) network. Herein, the reaction dynamics on the surface of ultradisperse diamond (UDD) due to the surface transformation or reconstruction during annealing in vacuum with temperatures ranging from ambient to 800 °C is described. In situ measurement of Fourier transform infrared spectroscopic analysis shows that low-temperature (<500 °C) annealing of UDD in vacuum results in isonitrile/isocyanide (−N═C:) and nitrile functionalization (−C≡N) on the surface. At temperatures ∼500 °C, the surface hydrogenation of UDD is initiated. During annealing at 780–800 °C, the nitrile group (−C≡N) is reduced to the primary amine (NH2), and isonitrile (−N═C:) turns it to be in the saturated () structure. On exposure to air, the obtained isonitrile is transformed to an N-formyl derivative (Aryl/R–NH–CHO) structure via hydrolysis. This study provides a fundamental insight into the surface reactive profile of UDD which could lead to facile surface functionalization properties and their applications in various fields such as biomedical, biosensing, drug delivery, epoxy materials process, tribology, and possibly in cyano (−C≡N/–N═C:) chemistry

Low temperature catalytic reactivity of nanodiamond in molecular hydrogen

In this paper, the reaction dynamics of hydrogen termination of nanodiamond annealed at low temperature (500 °C) in molecular hydrogen atmosphere is reported. In-situ residual gas analysis of nanodiamond particles (4–5 nm) during annealing/hydrogenation indicates C3-radical desorption which incites a free radical reaction through the reduction of molecular hydrogen to atomic hydrogen. Consequently, as released atomic hydrogen facilitates Csingle bondH adsorption on the surface of nanodiamond which was confirmed using infrared spectroscopy. This explains how nanodiamond particles can play a key role in hydrogen (H2) dissociation and be terminated by the hydrogen (H) at relatively low temperature

Study of nanoparticles interaction with biological tissues using comparative optical-spectroscopic methods

Abstract Recent development of nanoparticles bio-medical applications is determined by perspectives of their use for multimodal bio-imaging and sensing. Informative and noninvasive optical-spectroscopic methods are designed for the detection and analysis of the NP interaction with target biological systems. Presented work is focused on study of nanoparticles interaction with biological tissues combining complimentary methods to obtain versatile optical-spectroscopic information