Preparation of colloidal films with different degrees of disorder from monodisperse spherical silica particles

The process of coagulation of suspensions of monodisperse spherical silica particles driven by appropriate coagulants (NH₄Cl, HCl, C₁₆H₃₃N(CH₃)₃Br) has been studied. Films of photonic crystals and photonic glasses have been grown by the sedimentation method. The possibility of controlling the degree of structural disorder in colloidal films by properly varying the resistance of the water suspension of particles to aggregation has been demonstrated.     

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 Γ_H⁺(pH) and Γ_OH^-(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.     

Composite Films Based on Carbon Quantum Dots in a Matrix of PEDOT:PSS Conductive Polymer

Physics of the Solid State - Carbon quantum dots (CQDs), as well as their composites with the PEDOT:PSS conductive polymer, are hydrothermally synthesized from glucose, and their electrical...     

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

The pattern of previously recorded dependences of the specific surface charge and electrophoretic mobility of monodisperse detonation nanodiamond particles on pH of aqueous KCl solutions suggests that counterions are condensed on the particle surface. Counterion condensation is considered in terms of the Levin model, and the experimental ratios between the densities of the electrokinetic and surface charges of dispersed particles, as well as the fractions of condensed counterions, are calculated as depending on pH and KCl concentration in nanodiamond hydrosols. The obtained dependences lead to the conclusion that counterion condensation on the surface of detonation nanodiamond particles does indeed take place.     

Modification of the mechanism of proton conductivity of the perfluorinated membrane copolymer by nanodiamonds

Russian Chemical Bulletin - Proton conducting membranes based on a perfluorinated copolymer with short side chains (of the Aquivion® type) are promising for the use in hydrogen fuel cells and...     

Purines,pyrimidines, and condensed systems based on these compounds. 13. Transformation of fervenuli-1-oxide to 8-alkylaminotheophyllines under the action of alkylamines

Fervenulin-1-oxide undergoes reactions with secondary alkylamines in which the triazine ring is ruptured and 8-alkylaminotheophyllines are formed. The final product of the interaction of fervenulin-1-oxide with primary amines or with liquid ammonia is 1,3-dimethyl-5-imino-6-hydroximinouracil.For Communication 12, see [1].Rostov State University, Rostov-na-Donu 344104. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1253–1257, September, 1994. Original article submitted September 6, 1994.     

Template synthesis of monodisperse carbon nanodots

Monodisperse carbon nanodots in pores of mesoporous silica particles are obtained by template synthesis. This method is based on introducing a precursor (organosilane) into pores, its thermal decomposition with formation of carbon nanodots, and the template removal. Structural analysis of the nanomaterial has been performed, which showed that carbon nanodots have an approximately spherical form and a graphite-like structure. According to dynamic light scattering data, the size of carbon nanodots is 3.3 ± 0.9 nm.