Transport of a partially wetted particle at the liquid/vapor interface under the influence of an externally imposed surfactant generated Marangoni stress.

摘要: Abstract Marangoni flows offer an interesting and useful means to transport particles at fluid interfaces with potential applications such as dry powder pulmonary drug delivery. In this article, we investigate the of partially wetted a liquid/vapor interface under influence driven by gradients in surface excess concentration surfactants. We deposit microliter drop soluble (sodium dodecyl sulfate) aqueous surfactant solution or pure insoluble liquid (oleic acid) on water subphase observe pre-deposited particle. Following previous observation Wang et al. [1] that front rapidly advances ahead deposited contact line initiates particle motion but then moves beyond particle, now characterize two dominant, time- position-dependent forces acting moving particle: (1) tension force three-phase around periphery due gradient which always accelerates (2) viscous immersed area decelerates depending difference velocities find velocity evolves over time regimes. acceleration regime, net acts direction motion, quickly reaches maximum velocity. deceleration reverses gradually stops. identify parameters affect including initial position relative drop, diameter, wettability, thickness, solubility. systematically vary these probe spatial temporal evolution it along its trajectory both larger lags behind smaller when placed equal distance from drop. Similarly, more deeply engulfed lag those less engulfed. Further, extent is reduced thickness decreases recirculation flows.