Nucleation is one of the most important aspects of the gas hydrates (GH) kinetics that lays a basis to understanding of the GH formation in aqueous and/or water-bearing environments. It was suggested that nucleation most likely occurs on the solid substrates (impurity or micro particles) presented in the solution and/or at the solution/gas interface. Nucleation strongly depends on concentration and transport of new phase nuclei, which determine growth of GH clusters. Here we show that bubble propagation through oversaturated methane solutions, at certain conditions, could favor formation of gaseous clusters. Using a well-focused beam of a continuous wave visible laser (CWVL), we induced Maragoni convection, which developed near the surface of an ascending microbubble because of the temperature gradient at the solution/gas interface, in a colloidal solution loaded with CdTe nanoparticles of 4 nm in diameter. Dynamics of nanoparticles was recorded using a luminescence microscope. In a few seconds after the CWVL was turned on, concentration of nanoparticles on the surface of the microbubble started growing, forming a layer of nanoparticles covering the surface of the microbubble. This potentially creates conditions for formation of the colloidal crystal on the surface of the bubble (Fig.1).
Figure 1. Scheme of the mechanism of the new-phase nucleation on the surface of the bubble. 1 – CdTe nanoparticle (4 nm in diameter) distributed in the colloidal solution; 2 – Maragoni convection near the surface of the bubble; 3 – projection of the laser beam; 4 – starting point of the nucleation; 5 – layer of the nanoparticles resultant from the nucleation process.