Effect of capillary pressure in nanobubbles on their adhesion to particles under foam flotation. Part 3

The energy possibility of the transition of free bubbles A to adherent bubbles M, or the A -> M (TAM) transition, is calculated on substrates with different wetting abilities: extremely hydrophilic (I broken vertical bar), extremely hydrophobic (I), and with incomplete wetting ability (H (x) ), where x is the substrate surface fraction covered by a monolayer of collector molecules). Calculations of TAM for bubbles with a diameter (d (e) ) of 2 mm to 20 nm on I broken vertical bar, I, and H (x) substrates showed that the change in specific energy (Delta G/V) in a bubble in the case of TAM depends on the value of d (e) , substrate wetting ability, and surface area of its contact with the bubble. According to the results of studies, high capillary pressure (P (c)) in nanobubbles M promotes their instantaneous spreading over the substrate. Herewith, P (c) decreases considerably. The adhesion and spreading processes occur as a single process, irreversibly, one-way, and fast, because they are not complicated by counterprocesses. Upon a decrease in equatorial diameter d (e) and wetting ability of the substrate, the decrease in G/V reaches several million J/m(3). The actual simultaneity of the processes of bubble adhesion and spreading is illustrated by microphotographs of larger bubbles with a luminescent apolar reagent eliminating the effect of wetting hysteresis that is easily overcome in nanobubbles in the case of high P (c) values.