A multi-scale perspective of gas transport through soap-film membranes

Falciani, Gabriele; Franklin, Ricardo; Cagna, Alain; Sen, Indraneel; Hassanali, Ali; Chiavazzo, Eliodoro

doi:10.1039/c9me00186g

Cited by 20 publications

(32 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By using a range of diffusion coefficients (SI, Figure S5), simple diffusion theory with in situ bloom measurements can be used to extract real trends in permeability. 84 Representative diffusion coefficients ranging from 7 × 10 -5 cm 2 s -1 to 1 × 10 -5 cm 2 s -1 demonstrate the lower and upper bounds for several atmospheric gases in a range of ocean relevant temperatures. [85][86][87][88][89] Seemingly, as the film becomes more concentrated throughout the bloom and the film thickness increases, the film permeability decreases.…”

Section: Gas Transport and Atmospheric Implicationsmentioning

confidence: 92%

The Ocean’s Elevator: Evolution of the Air-Seawater Interface During a Small-Scale Algal Bloom

Rogers¹,

Neal²,

Saha³

et al. 2020

Preprint

View full text Add to dashboard Cite

We explore in situ the surface properties of marine algal blooms of diatom monocultures by utilizing surface techniques of Brewster angle microscopy (BAM) imaging, vibrational sum frequency generation spectroscopy (SFG), and infrared reflection absorption spectroscopy (IRRAS). Over the course of the bloom, the marine algae produce surface-active biogenic molecules that temporally partition to the topmost interfacial layers and are selectively probed through surface imaging and spectroscopic measurements. BAM images show morphological structural changes and heterogeneity in the interfacial films with increasing density of surface-active biogenic molecules. Film thickness calculations quantified the average surface thickness over time. The image results reveal an ~5 nm thick surface region in the late stages of the bloom which correlates to typical sea surface nanolayer thicknesses. Our surface-specific SFG spectroscopy results show significant diminishing in the intensity of the dangling OH bond of surface water molecules consistent with organic molecules partitioning and replacing water at the air-seawater interface as the algal bloom progresses. Interestingly, we observe a new broad peak appear between 3500 cm<sup>-1</sup> to 3600 cm<sup>-1</sup> in the late stages of the bloom that is attributed to weak hydrogen bonding interactions of water to the surface-active biogenic matter. IRRAS confirms the presence of organic molecules at the surface as we observe increasing intensity of vibrational alkyl modes and the appearance of a proteinaceous amide band. Our work shows the often overlooked but vast potential of tracking changes in the interfacial regime of small-scale laboratory marine algal blooms. By coupling surface imaging and vibrational spectroscopies to complex, time-evolving, marine-relevant systems, we provide additional insight into unraveling the temporal complexity of sea spray aerosol compositions.

show abstract

Section: Gas Transport and Atmospheric Implicationsmentioning

confidence: 92%

The Ocean’s Elevator: Evolution of the Air-Seawater Interface During a Small-Scale Algal Bloom

Rogers¹,

Neal²,

Saha³

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…We perform molecular-dynamics simulations of water-vapor and water-surfactant interfaces in a slab geometry [25,26,28] (Sec. III and Appendix D).…”

Section: (Sec III A)mentioning

confidence: 99%

“…These results suggest that the effective viscosity of water at the interface with vapor is smaller than near the surfactant film and also varies within the surfactant layer. This type of microscopic information will provide valuable input for continuum hydrodynamic models of gas diffusion through phase interfaces [28].…”

Section: Water-vapormentioning

confidence: 99%

See 1 more Smart Citation

Statistical physics of inhomogeneous transport: Unification of diffusion laws and inference from first-passage statistics

Belousov,

Hassanali,

Roldán

2021

Preprint

Self Cite

View full text Add to dashboard Cite

Characterization of composite materials, whose properties vary in space over microscopic scales, has become a problem of broad interdisciplinary interest. In particular, estimation of the inhomogeneous transport coefficients, e.g. the diffusion coefficient or the heat conductivity which shape important processes in biology and engineering, is a challenging task. The analysis of such systems is further complicated, because two alternative formulations of the inhomogeneous transport equations exist in the literature-the Smoluchowski and Fokker-Planck equations, which are also related to the so-called Ito-Stratonovich dilemma. Using the theory of statistical physics, we show that the two formulations, usually regarded as distinct models, are physically equivalent. From this result we develop efficient estimates for the transverse space-dependent diffusion coefficient in fluids near a phase boundary. Our method requires only measurements of escape probabilities and mean exit times of molecules leaving a narrow spatial region. We test our estimates in three case studies: (i) a Langevin model of a Büttikker-Landauer ratchet; atomistic molecular-dynamics simulations of liquid-water molecules in contact with (ii) vapor and (iii) soap (surfactant) film which has promising applications in physical chemistry. Our analysis reveals that near the surfactant monolayer the mobility of water molecules is slowed down almost twice with respect to the bulk liquid. Moreover, the diffusion coefficient of water correlates with the transition from hydrophilic to hydrophobic parts of the film.

show abstract

“… 6 − 12 More recently, they have also been considered for the building of photocatalytic soap films and monolayers, because the escape of O 2 , H 2 , or CO 2 -reduction products such as CO or CH 4 is easier at a water–gas interface than inside a liquid. 13 …”

Section: Introductionmentioning

confidence: 99%

Interfacial Characterization of Ruthenium-Based Amphiphilic Photosensitizers

Timounay¹,

Pannwitz

Klein

et al. 2022

Langmuir

Self Cite

View full text Add to dashboard Cite

Nonreactive surfactant molecules have long been used and characterized for a wide range of applications in industries, life science, and everyday life. Recently, new types of functional amphiphilic molecules have emerged that bear another function, for example, a light-absorbing action, or catalytic properties. However, the surfactant properties of these molecules remain to date essentially unknown. In this context, we investigated here the interfacial activity of photocatalytic surfactants based on a ruthenium(II) tris-bipyridine core, functionalized with two alkyl tails. We realized a systematic characterization of the surfactant properties of these molecules at a water–air interface and studied the effect of the alkyl chain length and of the counterions (hexafluorophosphate or chloride) on these properties. Our data demonstrate that ruthenium surfactants with chloride counteranions form a denser layer at the interface, but their surfactant properties can dramatically deteriorate when the chain length of the alkyl tail increases, leading to simple hydrophobic molecules with poor surfactant properties for the longest chains (C17). These findings pave the way for a better use and understanding of photocatalytic soft interfaces.

show abstract

A multi-scale perspective of gas transport through soap-film membranes

Abstract: A continuum–atomistic coupled model for gas permeation through soap-film membranes.

Cited by 20 publications

References 46 publications

The Ocean’s Elevator: Evolution of the Air-Seawater Interface During a Small-Scale Algal Bloom

The Ocean’s Elevator: Evolution of the Air-Seawater Interface During a Small-Scale Algal Bloom

Statistical physics of inhomogeneous transport: Unification of diffusion laws and inference from first-passage statistics

Interfacial Characterization of Ruthenium-Based Amphiphilic Photosensitizers

Contact Info

Product

Resources

About