The Structure of the Surfaces of Liquids, and Solubility as Related to the Work Done by the Attraction of Two Liquid Surfaces as They Approach Each Other. [Surface Tension. V.]

Harkins, William D.; Brown, F. E.; Davies, Earl C. H.

doi:10.1021/ja02248a003

Cited by 99 publications

(29 citation statements)

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“…The extent of water self association due to LW interactions can be estimated from interfacial-tension-component theory and measurement of interfacial tensions between water (phase 1) and saturated hydrocarbons (phase 2) for which no AB interaction across the interface between phase 1 and 2 (12) is possible. Choosing hexane as an example, it is found experimentally that

γ_{2 ν} = γ_{2 ν}^{italicLW} = 18.4 mJ ∕ {normalm}^{2}

and

γ_{12}^{italicLW} = 51.1 mJ ∕ {normalm}^{2}

[171, 172]. Using

72.8 mJ ∕ {normalm}^{2} = γ_{normal 1 ν}^{LW} + γ_{normal 1 ν}^{AB}

for water at 20 °C in the traditional geometric-mean equation (

γ_{12} = γ_{1 ν} + γ_{2 ν} - 2 \sqrt{γ_{1 ν}^{italicLW} γ_{2 ν}^{italicLW}}

) [171, 173, 174] calculates that

γ_{1 ν}^{italicLW} = 21.8 mJ ∕ {normalm}^{2}

, or about 29% of the total interfacial tension of water.…”

Section: 0 Technical Backgroundmentioning

confidence: 99%

Protein adsorption in three dimensions

2012

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Recent experimental and theoretical work clarifying the physical chemistry of blood-protein adsorption from aqueous-buffer solution to various kinds of surfaces is reviewed and interpreted within the context of biomaterial applications, especially toward development of cardiovascular biomaterials. The importance of this subject in biomaterials surface science is emphasized by reducing the “protein-adsorption problem” to three core questions that require quantitative answer. An overview of the protein-adsorption literature identifies some of the sources of inconsistency among many investigators participating in more than five decades of focused research. A tutorial on the fundamental biophysical chemistry of protein adsorption sets the stage for a detailed discussion of the kinetics and thermodynamics of protein adsorption, including adsorption competition between two proteins for the same adsorbent immersed in a binary-protein mixture. Both kinetics and steady-state adsorption can be rationalized using a single interpretive paradigm asserting that protein molecules partition from solution into a three-dimensional (3D) interphase separating bulk solution from the physical-adsorbent surface. Adsorbed protein collects in one-or-more adsorbed layers, depending on protein size, solution concentration, and adsorbent surface energy (water wettability). The adsorption process begins with the hydration of an adsorbent surface brought into contact with an aqueous-protein solution. Surface hydration reactions instantaneously form a thin, pseudo-2D interface between the adsorbent and protein solution. Protein molecules rapidly diffuse into this newly-formed interface, creating a truly 3D interphase that inflates with arriving proteins and fills to capacity within milliseconds at mg/mL bulk-solution concentrations CB. This inflated interphase subsequently undergoes time-dependent (minutes-to-hours) decrease in volume VI by expulsion of either-or-both interphase water and initially-adsorbed protein. Interphase protein concentration CI increases as VI decreases, resulting in slow reduction in interfacial energetics. Steady-state is governed by a net partition coefficient P=true(/CBCItrue). In the process of occupying space within the interphase, adsorbing protein molecules must displace an equivalent volume of interphase water. Interphase water is itself associated with surface-bound water through a network of transient hydrogen bonds. Displacement of interphase water thus requires an amount of energy that depends on the adsorbent surface chemistry/energy. This “adsorption-dehydration” step is the significant free-energy cost of adsorption that controls the maximum amount of protein that can be adsorbed at steady state to a unit adsorbent-surface area (the adsorbent capacity). As adsorbent hydrophilicity increases, protein adsorption monotonically decreases because the energetic cost of surface dehydration increases, ultimately leading to no protein adsorption near an adsorbent water wettability (surface energy) characterized ...

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γ_{2 ν} = γ_{2 ν}^{italicLW} = 18.4 mJ ∕ {normalm}^{2}

and

γ_{12}^{italicLW} = 51.1 mJ ∕ {normalm}^{2}

[171, 172]. Using

72.8 mJ ∕ {normalm}^{2} = γ_{normal 1 ν}^{LW} + γ_{normal 1 ν}^{AB}

for water at 20 °C in the traditional geometric-mean equation (

γ_{12} = γ_{1 ν} + γ_{2 ν} - 2 \sqrt{γ_{1 ν}^{italicLW} γ_{2 ν}^{italicLW}}

) [171, 173, 174] calculates that

γ_{1 ν}^{italicLW} = 21.8 mJ ∕ {normalm}^{2}

, or about 29% of the total interfacial tension of water.…”

Section: 0 Technical Backgroundmentioning

confidence: 99%

Protein adsorption in three dimensions

2012

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“…Langmuir (49) in 1917 (cf. Harkins [50][51]) showed that some lipid molecules were amphiphilic (52), in having a polar head and a nonpolar carbon chain. When spread at an air-water interface, they formed a monolayer on the surface and affected the surface tension .…”

Section: Historical Background Before the Electron Microscope E A R Lmentioning

confidence: 99%

Membrane structure.

Robertson¹

1981

The Journal of Cell Biology

101

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“…CC BY 4.0 License. (Richards and Coombs, 1915) Ethyl Acetate 23.246 0.069 23.95 (Mumford and Phillips, 1950) Acetonitrile 27.888 0.064 29.04 (Harkins et al, 1917) Glycerol 63.686 0.057 64.800 (Vargo et al, 1991) Pure Water 70.335 0.089 72.703 (Vargaftik et al, 1983) Salt Water 71.478 0.092 74.876 (Nayar et al, 2014) https://doi.org/10.5194/os-2019-87 Preprint. Discussion started: 1 August 2019 c Author(s) 2019.…”

Section: Discussionmentioning

confidence: 99%

“…Surface tension was measured using Du Noüy Ring tensiometry (Harkins et al, 1917;Noüy, 1925) performed using an Attension Sigma 70 instrument with thermocouple (density resolution: 1 x 10 -4 g cm -3 , force resolution: 0.1 μN) which was calibrated daily. The short-term precision of the instrument, as measured from ~100 repeat measurements, was typically 0.05-0.1 mN m -1 .…”

Section: Surface Tension Measurementsmentioning

confidence: 99%

The Determination of Surfactants at the Sea Surface

King

Roberts

Tinel

et al. 2019

Preprint

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Abstract. The surface of the ocean is a critical yet little understood interface that covers more than 70 % of the Earth's surface. Evidence is emerging that the so-called sea surface microlayer (SML) – the thin film of the ocean surface which is enriched in surface active material and contains large chemical, physical and biological gradients that separate it from the underlying seawater – plays an important role in regulating the air-sea exchange of gases and aerosols. Indeed, recent studies have suggested that (a) there is a ubiquitous enrichment of surfactants in the SML even at high wind speeds; (b) surfactants exert a control on air-sea CO2 exchange at the ocean basin scale, even at high wind, high latitude oceans, and (c) interfacial photochemistry within the SML serves as a major global abiotic source of volatile organic compounds (VOCs), competitive with emissions from marine biology. These conclusions are based on measurements of surfactant activity (SA) from alternating current (AC) voltammetry, showing enrichment of SA in the SML compared to subsurface waters at the ocean basin scale even at high wind speeds, and a relationship between SA and suppression of air-sea gas exchange. SA is calibrated using the large non-ionic surfactant Triton X-100 (TX-100) and expressed in concentration units of TX-100 equivalents. Here, we show that the response of SA-voltammetry varies widely for different surfactants, depending on the surfactant's molecular weight and its charge. Further, even at short deposition times of 15 s, the response becomes saturated above total surfactant concentrations of 1–2 mg L-1, which are at the high end of those observed in the SML. This behaviour was also observed when comparing measurements of seawater and lake water by SA voltammetry to surface film pressure (Δγ) measured by tensiometry. These two different methods for assessing the presence of surfactants showed that, while SA generally increases as surface film pressure increases, the correlation is poor and SA values plateau above ∼2 mg L-1 TX-100 eq. The implications of these results are that SA might not accurately capture variations in soluble and insoluble surfactants present in ocean waters.

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The Structure of the Surfaces of Liquids, and Solubility as Related to the Work Done by the Attraction of Two Liquid Surfaces as They Approach Each Other. [Surface Tension. V.]

Cited by 99 publications

References 0 publications

Protein adsorption in three dimensions

Protein adsorption in three dimensions

Membrane structure.

The Determination of Surfactants at the Sea Surface

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