A. N. Zhukov

Electrosurface properties of single-crystalline detonation nanodiamond particles obtained by air annealing of their agglomerates

A complex study of electrosurface properties has been performed for single-crystalline detonation nanodiamond particles with sizes of 4–5 nm obtained by air annealing of their agglomerates. FTIR spectroscopy and X-ray photoelectron spectroscopy data indicate that the investigated properties result from the presence of two types of ionogenic functional groups on the particle surface, i.e., acidic carboxyl and amphoteric hydroxyl groups. Acid-base potentiometric titration, laser Doppler electrophoresis, and conductometry have been employed to measure the ΓH+(pH) and ΓOH-(pH) adsorption isotherms of potential-determining ions, as well as the pH dependences (in a pH range of 3.5–10.5) of the surface charge density, electrophoretic mobility, and specific surface conductivity of detonation nanodiamond particles in aqueous 0.0001–0.01 M KCl solutions.

Surface Charge of Detonation Nanodiamond Particles in Aqueous Solutions of Simple 1: 1 Electrolytes

Adsorption isotherms of potential-determining H+ and OH− ions and the pH dependences of the specific surface charge of detonation nanodiamond (DND) particles are obtained in a pH range of 3–10 by the acid-base titration of their hydrosols containing 0.001–1 M LiCl, NaCl, KCl, NaNO3, KNO3, and NaClO4 as background electrolytes. The data obtained attest to the chemical nonuniformity (heterogeneity) of a DND surface and different degrees of binding of background electrolyte cations and anions with ionized groups. It is revealed that the adsorption of OH-anions diminishes in the lyotropic series of cations Na+ > K+ > Li+ and increases with a decrease in the adsorbability of anions in the following series: NO3− ≊ ClO4− > Cl−. The adsorption of potential-determining H+ and OH− ions on a DND surface containing two types of functional groups, i.e., acidic carboxyl and amphoteric hydroxyl groups, is simulated by the Protofit software package. The optimal surface densities and ionization constants that correspond to minimal deviations of model adsorption isotherms from the experimental curves are found for these groups.

Comprehensive study of electrosurface properties of detonation nanodiamond particle agglomerates in aqueous KCl solutions

The electrosurface properties of nanoporous agglomerates of detonation nanodiamond (DND) particles purified from acidic impurities by dialysis are comprehensively investigated. Acid-base potentiometric titration, laser Doppler electrophoresis, and conductometry are employed to measure the adsorption isotherms

Octadecylamine-based Langmuir-Blodgett films containing iron and copper hexacyanoferrates

\Gamma _{H^ + } (pH)

Conductivity and Electrokinetic Potential of Microcrystalline Cellulose Particles in Aqueous HCl and NaOH Solutions

and

Counterion condensation in hydrosols of single-crystalline detonation nanodiamond particles obtained by air annealing of their agglomerates

\Gamma _{OH^ - } (pH)