Figure 6
From: How dynamic adsorption controls surfactant-enhanced boiling
Surfactants with different CMCs and equilibrium surface tensions have similar dynamic adsorption behaviors at short time scales when at the same concentration. We performed (a) dynamic pendant bubble experiments to measure, using Young–Laplace fitting, (b) time-dependent surface tension of two surfactants: TW20 and TW40 at room temperature (25 °C) were used for testing at two different surfactant concentration amounts in DI water. The CMCs of TW20 and TW40 are 0.05 mol/m3 and 0.02 mol/m3, respectively. At 0.015 mol/m3 the equilibrium surface tensions are 47.66 ± 0.08 mN/m and 43.99 ± 0.09 mN/m, respectively. At 0.03 mol/m3 the equilibrium surface tensions are 44.22 ± 0.09 mN/m and 42.55 ± 0.01 mN/m, respectively. Despite the differences in equilibrium surface tensions, both surfactants had similar dynamic surface tensions, meaning that they have similar dynamic adsorption behaviors when at the same concentrations. The timescale of this similar dynamic adsorption (the diffusion timescale), decreases with increasing surfactant concentration.
