The methods of low-temperature ¹H NMR and IR spectroscopy, densitometry, and adsorption from solutions are applied to study the influence of “wetting–drying” compaction on the adsorptive characteristics of the nanosilica A-300 in relation to water and gelatin. It was shown that if the bulk density changes from 0.05 to 0.25 g/ml, the protein adsorptive capacity of the nanosilica decreases no more than by 30%, which, apparently, is connected with the decrease of the part of the surface, available for the protein molecules. Interfacial energy in relation to water increases from 37 to 52 mJ/m² if the bulk density increases and this is connected with the increase of the contribution from minor clusters (nanodrops) adsorbed on the surface water.

Polymethylsiloxane (PMS) and fumed silica, alone and in a blended form (1:1 w/w), differently pretreated, hydrated, and treated again, were studied using TEM and SEM, nitrogen adsorption–desorption, ¹H MAS and ²⁹Si CP/MAS NMR spectroscopy, infrared spectroscopy, and methods of quantum chemistry. Analysis of the effects of adding water (0–0.5 g of water per gram of solids) to the blends while they are undergoing different mechanical treatment (stirring with weak (~1–2 kg/cm²) and strong (~20 kg/cm²) loading) show that both dry and wetted PMS (as a soft material) can be grafted onto a silica surface, even with weak mechanical loading, and enhanced mechanical loading leads to enhanced homogenization of the blends. The main evidence of this effect is strong nonadditive changes in the textural characteristics, which are 2–3 times smaller than additive those expected. All PMS/nanosilica blends, demonstrating a good distribution of nanosilica nanoparticles and their small aggregates in the polymer matrix (according to TEM and SEM images), are rather meso/microporous, with the main pore-size distribution peaks at R > 10 nm in radius and average <R_V> values of 18–25 nm. The contributions of nanopores (R < 1 nm), mesopores (1 nm < R < 25 nm), and macropores (25 nm < R < 100 nm), which are of importance for studied medical sorbents and drug carriers, depend strongly on the types of the materials and treatments, as well the amounts of water added. The developed technique (based on small additions of water and controlled mechanical loading) allows one to significantly change the morphological and textural characteristics of fumed silica (hydrocompaction), PMS (drying–wetting–drying), and PMS/A-300 blends (wetting–drying under mechanical loading), which is of importance from a practical point of view.

The hydration of systems obtained via the adsorption of alkali metal chlorides on A-300 nanosilica is studied by means of low-temperature ¹H NMR spectroscopy. It is shown that in weakly polar organic media, adsorbed water is present in the form of weakly and strongly associated water. A reduction in the differentiation of adsorbed water in the SiO₂/NaCl > SiO₂/KCl > SiO₂/LiCl series of composites is established that could be due to changes in the lattice parameters of SiO₂. Quantum-chemical calculations are performed for the ¹H NMR spectra of complexes containing clusters of Si₈O₁₂(OH)₈ and hydrated ion pairs of alkali metal chlorides. These calculations allow us to explain the displacement in the chemical shifts of water protons.

The process of formation of composite systems based on nanosilica A-300 and biologically active substances (BAS), namely gallic acid (GA), glycyrrhizic acid (GLA), and its salts, was studied using a set of physicochemical methods. It was shown that when BAS are immobilized on the silica surface by the method of joint grinding in a porcelain mortar, they pass into a nanosized X-ray amorphous state. Water adsorbed on the surface of such composite systems is also in a clustered state, and the radius of adsorbed water clusters is in the range of 0.4–50 nm. The chloroform environment has a complex effect on the size of water clusters. In general, there is a tendency for the radius of water clusters to increase when air is replaced by a chloroform environment. However, this does not always lead to a decrease in the interfacial energy. The possibility of the existence of metastable ice in the temperature range up to 287 K, stabilized by the surface of composite systems, was discovered. The amount of such ice can reach 20% of the total water content in the sample. The possibility of using complex viscosity measurements for hydrated silica powders and silica containing immobilized biologically active substances was shown. These measurements allow recording changes in the phase state of complex mixtures during the formation of compact composite forms under the influence of periodic mechanical loading.