**Author details**

240 Nitroxides – Theory, Experiment and Applications

and OH-

compounds.

related CMs and hybrid materials ; metal-containing systems, as compared to those of external solution can be explained by releasing H+ ions due to dissociation of acidic functional groups, exchange them with metal ions and the partial desruption of hydrogen bonds. It leads to negative charge of a surface of the above-mentioned objects. A decrease in concentration of H+ ions (an increase in pHint) as compared to those of external solution were characteristic for γ-Al2O3 and cellulose matrixes. This resulted from binding H+-ions by the surface of γ-Al2O3 and MCC and PC with basic functional groups such as -AlOH , –AlO -

The sorption capacity of Cu2+ ions depends on a surface charge of the oxides gels, xerogels and the related CMs studied and decreases as a negative surface charge reduces. The sorption of Cu2+ ions on the surface of nanoparticles of nanostructural TiO2 increases the charge of the latter. An increase in a percentage of PC in the SiO2 –PC composites leads to an increase in the amount of silanol groups as a result of increasing in dispersivity of SiO2 particles and specific surface (Ssp) of the samples, and to reducing a negative surface charge

The deposition of chitosan on the substrate always creates a negative charge on the surface. While the deposition of chitosan leads to relatively slight changes in the surface potential in the case of inorganic substrates such as Al2O3 and SiO2, these changes are so great in the case

The charge of the surface of Co2+-modified organo-inorganic hybrid materials at different pHint was found to effect on the composition and structure of Co2+ -containing surface

The modification of a surface of powder cellulose with nanostructured SiO2 and TiO2 xerogels, aluminum oxides, silica and MCC with acidic functional groups and chitosan

The study of the surface of organo–inorganic composites and hybrid materials and systems using pH-sensitive nitroxyl radicals allows also to reveal regularities in changing their properties during further modification. In addition, this method enables us to describe qualitatively the processes of structure formation in these systems and their effect on

The calculated φ value (31.7 mV) was found not to be the electric potential of TiO2 nanoparticle surface, but it only characterizes the electric eld generated by a nanoparticle at the site where the radical fragment –N–O• of NR is located. Once the anisotropic spectra of NR in nanostructured oxides are simulated, an electical potential of a surface can be determined. When measuring the SEP of solids, the knowledge of the distance between a radical and a surface is of principal importance. The xation of pH-sensitive NRs on the surface of nanoparticles with linkers of a known length can solve this problem. This will allow one to calculate the potential immediately on the surface of nanoparticles and to compare the calculation results with the experimental data on the electrokinetic potentials.

makes it possible to adjust the local acidity and surface charge over a wide range.

, respectively. As a result, a surface gains a positive charge.

up to zero, and even its reversing. It led to the formation of Cu(OH)2 .

of MCC that they even lead to changes in the surface charge.

catalytic activity in different pH-dependent reactions.

Elena Kovaleva\* *Ural Federal University,Russia* 

Leonid Molochnikov *Ural State Forest Engineering University, Russia* 
