Figure 2.

The data presented in this figure is from work completed by Ghadiali et al. (17), who investigated surfactant uptake during the steady propagation of a finger of air. In this instance, interfacial adsorption of the pulmonary surfactant replacement Infasurf was inadequate and resulted in elevated reopening pressures and interfacial rigidification. The experiments were performed at a velocity of 0.22 cm/s. $P_{\text{cap}}/({\gamma }_{\text{eq}}/R)$ represents the equilibrium pressure that would exist if surfactant adsorbed rapidly enough for surfactant to achieve the equilibrium surface tension and $C^{\ast }/C_{\text{cbc}}$ is the dimensionless bulk surfactant concentration where $C_{\text{cbc}}$ is the critical bulk concentration. The interface is saturated with surfactant when $C>C_{\text{cbc}}$.