Digital control of the spatio-temporal thermal structures in a droplet reactor

Muradkhanyan N.A., Zhukalin D.A.

Voronezh State University

Self-organization is one of the most important processes that must be taken into account when forming nanostructured materials. Local interactions of nanocomponents in an active medium under controlled initial conditions open up new possibilities for the formation of hierarchically related structures.

The structural evolution of drying drops of colloidal solutions is a complex of complex physicochemical and mechanical processes, united by the concept of dehydration self-organization. A drying drop is considered as a nanoreactor with constantly changing parameters: concentration, radius of curvature, surface tension, temperature. In 2009, at the Institute of Theoretical Physics. L. D. Landau RAS successfully defended the dissertation of L. Yu. Barash “Evaporation and dynamics of a droplet lying on a substrate”. Interest in the physics of the process of droplet evaporation is growing every year from both theorists [1] and practitioners [2,3].

In the study of nonlinear thermal dynamic processes during the aggregation of materials of various nature in the drying drops of their aqueous colloidal suspensions, the phenomenon of the formation of thermal autowave space-time structures was observed. According to its distinguishing features (nonequilibrium, nonlinearity, spontaneity, openness), the autowave aggregation process belongs to dissipative structures with an increasing amplitude of temperature fluctuations.

The in situ aggregation process and the kinetics of thermophysical processes in the IR range were controlled by a ThermaCAM SC 3000 thermal imager with a temperature sensitivity of 20 mK.

It is established that thermal autowave processes are a thermodynamic characteristic of self-organization, and can be used for diagnostics in obtaining functional materials for various purposes. A drop can be considered as a hydrodynamic reactor in which the interaction energy of the components leads to the formation of localized dissipative structures. The presence of interaction in the system leads to competition between hydrodynamic heat fluxes generated by droplet evaporation and interacting components.

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