Dissipative structures in thin films of cavitation-activated soot suspensions

Abstract

This paper presents analysis of optical images of films obtained by evaporation (293 K) of a thin layer of low-concentrated (1% wt.) aqueous soot suspensions in a Petri dish. Suspensions of wood, fullerene and diamond-containing (after detonation synthesis) soot were prepared using hydrodynamic dispersion in a cavitation mixer with a wedge-shaped cavitator with the rotor's angular velocity of rotation being 10000 rpm. The components of the hydrodynamic dispersion process are turbulent micro-mixing and bubble cavitation. As a result of intense turbulence, carbon suspensions assumed properties of non-equilibrium systems. The images of an optical microscope revealed self-organized dissipative micron-sized structures in the dried films being present there in the form of chain, branched and ring-shaped cluster fractals of various dimensions that look very similar to nanotubes. The self-assembling effect was identified for all the types of suspensions under study. The EPR method was used to study the change in the electronic structure of soot resulting from the exposure to high temperatures and pressures that occur when the cavitation bubbles collapse (cavitational activation). The dynamics of changes in dissipative structures in the process of film drying was monitored.