Spreading of surfactant solutions over thin aqueous layers at low concentrations: Influence of solubility

Lee, Khai S.; Starov, Victor

doi:10.1016/j.jcis.2008.10.031

Cited by 34 publications

(30 citation statements)

References 6 publications

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“…19). The time evolution of the radius of the moving front can be monitored and information on the properties of surfactants can be extracted [52][53][54][55]. In [53] surfactants of different solubility were used at concentrations above CMC.…”

Section: Spreading Of Surfactants Over Thin Viscous Liquid Layersmentioning

confidence: 99%

Surface forces action in a vicinity of three phase contact line and other current problems in kinetics of wetting and spreading

Starov

2010

Advances in Colloid and Interface Science

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Section: Spreading Of Surfactants Over Thin Viscous Liquid Layersmentioning

confidence: 99%

Surface forces action in a vicinity of three phase contact line and other current problems in kinetics of wetting and spreading

Starov

2010

Advances in Colloid and Interface Science

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“…Further, surfactant escapes across the contact line of the drop, lowering the surface tension of the subphase/vapor interface. (23,24) As shown in Figure 1, these altered surface tensions can result in a lens that covers an area larger than that of a surfactant-free drop. In the cases examined here, where the drop and subphase are miscible, the effective surface tension at the drop/ subphase interface is very small, (25,26) such that the final area covered by the spread surfactant-laden drop is increased relative to the surfactant-free drop if the initial drop/vapor surface tension is smaller than the initial surface tension of the subphase.…”

Section: Theorymentioning

confidence: 99%

Surfactant Driven Post-Deposition Spreading of Aerosols on Complex Aqueous Subphases. 1: High Deposition Flux Representative of Aerosol Delivery to Large Airways

Khanal

Sharma

Corcoran

et al. 2015

Journal of Aerosol Medicine and Pulmonary Drug Delivery

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Background: Aerosol drug delivery is a viable option for treating diseased airways, but airway obstructions associated with diseases such as cystic fibrosis cause non-uniform drug distribution and limit efficacy. Marangoni stresses produced by surfactant addition to aerosol formulations may enhance delivery uniformity by postdeposition spreading of medications over the airway surface, improving access to poorly ventilated regions. We examine the roles of different variables affecting the maximum post-deposition spreading of a dye (drug mimic). Methods: Entangled aqueous solutions of either poly(acrylamide) (PA) or porcine gastric mucin (PGM) serve as airway surface liquid (ASL) mimicking subphases for in vitro models of aerosol deposition. Measured aerosol deposition fluxes indicate that the experimental delivery conditions are representative of aerosol delivery to the conducting airways. Post-deposition spreading beyond the locale of direct aerosol deposition is tracked by fluorescence microscopy. Aqueous aerosols formulated with either nonionic surfactant (tyloxapol) or fluorosurfactant (FS-3100) are compared with surfactant-free control aerosols. Results: Significant enhancement of post-deposition spreading is observed with surfactant solutions relative to surfactant-free control solutions, provided the surfactant solution surface tension is less than that of the subphase. Amongst the variables considered-surfactant concentration, aerosol flow-rate, total deposited volume, time of delivery, and total deposited surfactant mass-surfactant mass is the primary predictor of maximum spread distance. This dependence is also observed for solutions deposited as a single, microliter-scale drop with a volume comparable to the total volume of deposited aerosol. Conclusions: Marangoni stress-assisted spreading after surfactant-laden aerosol deposition at high fluxes on a complex fluid subphase is capable of driving aerosol contents over significantly greater distances compared to surfactant-free controls. Total delivered surfactant mass is the primary determinant of the extent of spreading, suggesting a great potential to extend the reach of aerosolized medication in partially obstructed airways via a purely physical mechanism.

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“…Similar movement of solid particles at a liquid surface under the action of Marangoni stresses has been reported before. (17,20,36) This convection of the subphase surface is responsible for the post-deposition convection of the aerosol droplet field.…”

Section: Figmentioning

confidence: 99%

“…This escaped surfactant may travel distances that are significantly larger than the final diameter of the spread drop. (18,20,21) It is uncertain how well microliter-scale drop spreading behavior translates to sub-picoliter scale aerosol droplets. While the basic spreading mechanism of an individual subpL aerosol droplet after deposition should be similar to that of a microliter drop, the much larger surface-to-volume ratio of aerosol droplets suggests that surfactant depletion from the small aerosol droplet should occur much more rapidly, perhaps defeating the spreading enhancement.…”

Section: Introductionmentioning

confidence: 99%

Surfactant Driven Post-Deposition Spreading of Aerosols on Complex Aqueous Subphases. 2: Low Deposition Flux Representative of Aerosol Delivery to Small Airways

Sharma

Khanal

Corcoran

et al. 2015

Journal of Aerosol Medicine and Pulmonary Drug Delivery

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Background: Cystic fibrosis (CF) is associated with the accumulation of dehydrated mucus in the pulmonary airways. This alters ventilation and aerosol deposition patterns in ways that limit drug delivery to peripheral lung regions. We investigated the use of surfactant-based, self-dispersing aerosol carriers that produce surface tension gradients to drive two-dimensional transport of aerosolized medications via Marangoni flows after deposition on the airway surface liquid (ASL). We considered the post-deposition spreading of individual aerosol droplets and two-dimensional expansion of a field of aerosol droplets, when deposited at low fluxes that are representative of aerosol deposition in the small airways. Methods: We used physically entangled aqueous solutions of poly(acrylamide) or porcine gastric mucin as simple ASL mimics that adequately capture the full miscibility but slow penetration of entangled macromolecular chains of the ASL into the deposited drop. Surfactant formulations were prepared with aqueous solutions of nonionic tyloxapol or FS-3100 fluorosurfactant. Fluorescein dye served as a model ''drug'' tracer and to visualize the extent of post-deposition spreading. Results: The surfactants not only enhanced post-deposition spreading of individual aerosol droplets due to localized Marangoni stresses, as previously observed with macroscopic drops, but they also produced largescale Marangoni stresses that caused the deposited aerosol fields to expand into initially unexposed regions of the subphase. We show that the latter is the main mechanism for spreading drug over large distances when aerosol is deposited at low fluxes representative of the small airways. The large scale convective expansion of the aerosol field drives the tracer (drug mimic) over areas that would cover an entire airway generation or more, in peripheral airways, where sub-monolayer droplet deposition is expected during aerosol inhalation. Conclusions:The results suggest that aerosolized surfactant formulations may provide the means to maximize deposited drug uniformity in and access to small airways.

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Spreading of surfactant solutions over thin aqueous layers at low concentrations: Influence of solubility

Cited by 34 publications

References 6 publications

Surface forces action in a vicinity of three phase contact line and other current problems in kinetics of wetting and spreading

Surface forces action in a vicinity of three phase contact line and other current problems in kinetics of wetting and spreading

Surfactant Driven Post-Deposition Spreading of Aerosols on Complex Aqueous Subphases. 1: High Deposition Flux Representative of Aerosol Delivery to Large Airways

Surfactant Driven Post-Deposition Spreading of Aerosols on Complex Aqueous Subphases. 2: Low Deposition Flux Representative of Aerosol Delivery to Small Airways

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