The prevailing opinion in the literature is that the main mechanism of O/W nanoemulsion degradation is Ostwald ripening. Nevertheless, the experimental rates of Ostwald ripening are usually several orders of magnitude higher than the theoretical values. This suggests that other mechanisms, such as coalescence, flocculation and subsequent creaming, significantly influence nanoemulsion breakdown. We investigated O/W nanoemulsions stabilized by Brij 30 or by a mixture of Tween 80 and Span 80 and with liquid paraffin as a dispersed phase. The results indicate that Ostwald ripening is the main process leading to nanoemulsion coarsening only in nanoemulsions with low oil phase fractions of up to 0.05. For quasi-steady state conditions the rates of Ostwald ripening are equal to (1.5 ± 0.3) × 10⁻²⁹ and (1.1 ± 0.3) × 10⁻²⁹ m³ s⁻¹ in nanoemulsions with Brij 30 and Tween 80 & Span 80, respectively. In nanoemulsions with oil phase fractions of 0.15–0.45, different mechanisms are identified. Flocculation prevails over other processes during the first days in nanoemulsions stabilized by Brij 30. Coalescence is the main mechanism of nanoemulsion degradation for long times. An increase in droplet size 5–10 days after nanoemulsion preparation due to Ostwald ripening takes place in the case of nanoemulsion stabilization by Tween 80 and Span 80. The stability behavior of these nanoemulsions at later stages is distinctly affected by coalescence and flocculation.

Characteristic features of the Ostwald ripening in oil-in-water and water-in-oil macro- and nanoemulsions are analyzed. Methods for reducing the ripening rate are considered. It is shown that Ostwald ripening is especially relevant for nanoemulsions, and this is often the main process leading to degradation of nanoemulsions, thus limiting their practical applications. Considerable attention is paid to the debatable issue of the role of surfactants in the mass transfer between the droplets of the dispersed phase. Analysis of published sources shows that if the solubility of the dispersed phase substance in the dispersion medium is not extremely low, then the major contribution to Ostwald ripening is made by molecular diffusion. If the solubility of the dispersed phase substance is very low, then micelles and nanodroplets are the most likely carriers of the substances through the dispersion medium. Nanodroplets and slightly larger droplets are formed on the surface of droplets of the starting emulsion because of the interfacial instability (Marangoni effect). The bibliography includes 204 references.

Energetic materials (EMs) are the core materials of weapons and equipment. Achieving precise molecular design and efficient green synthesis of EMs has long been one of the primary concerns of researchers around the world. Traditionally, advanced materials were discovered through a trial-and-error processes, which required long research and development (R&D) cycles and high costs. In recent years, the machine learning (ML) method has matured into a tool that compliments and aids experimental studies for predicting and designing advanced EMs. This paper reviews the critical process of ML methods to discover and predict EMs, including data preparation, feature extraction, model construction, and model performance evaluation. The main ideas and basic steps of applying ML methods are analyzed and outlined. The state-of-the-art research about ML applications in property prediction and inverse material design of EMs is further summarized. Finally, the existing challenges and the strategies for coping with challenges in the further applications of the ML methods are proposed.

Pickering emulsions are emulsions that are stabilized by solid micro- and nanoparticles. These emulsions are in most demand for applications where the use of surfactants is restricted. The review addresses stabilization of Pickering emulsions. The attention is focused on the flocculation, coalescence, sedimentation and Ostwald ripening processes taking place in these emulsions. The structures formed by particles in the emulsion dispersion medium and in thin interlayers between the dispersed phase droplets are analyzed. Methods for preparing colloidosomes, that is, microcapsules of assembled particles, from Pickering emulsions are considered. Colloidosomes are promising for the encapsulation and prolonged release of active substances. Conversely, Pickering stimuli-responsive emulsions provide intense release of encapsulated substances upon the change in the environmental parameters. This can be used not only in medicine and pharmacology, but also in sensors, food industry, paint and varnish industry, petroleum production, etc. The bibliography includes 340 references