Scaling regimes for unsteady diffusion across particle-stabilized fluid interfaces

Colloidal particles at fluid interfaces stabilize drops and bubbles, yet their effect on mass transfer remains ambiguous, with experiments showing either strong hindrance or minimal effect, even at near-complete surface coverage. We resolve this ambiguity by modeling transient diffusion with the Fick-Jacobs equation, revealing that particle layers hinder diffusion only at short times due to reduced cross-sectional area. Our model provides a simple criterion for predicting hindered diffusion and captures prior experimental findings into a regime map, offering a unifying framework for diffusion in particle-stabilized multiphase systems.