Thermodynamics of some perfluorocarbon gases in water

Wen, Wen-Yang; Muccitelli, John A.

doi:10.1007/bf00648882

Cited by 58 publications

(36 citation statements)

References 49 publications

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“…In the case of hydrocarbon surfactants it has been shown that the total hydrophobic contributions to free energy changes derive from the interactions among chains and interactions responsible for removing the chains from water [60]; thus the roughly similar free energies of micelle formation for C10HONa/C7FONa and C12HONa/C8FONa indicate a significantly greater contribution to the free energy arising from the removal of the chain from water for the fluorocarbon surfactant. In fact, it has been demonstrated that fluorocarbon gases are less soluble in water than the corresponding hydrocarbon ones [64]. Ravey and Stebe [65] have shown that hydrogen and fluorine in the surfactant chain create different cavities in the water, which explains the differences in their hydrophobicity.…”

Section: Thermodynamics Of Micellizationmentioning

confidence: 98%

A comparative study of the physicochemical properties of perfluorinated and hydrogenated amphiphiles

Blanco

González‐Pérez

Ruso

et al. 2005

Journal of Colloid and Interface Science

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Section: Thermodynamics Of Micellizationmentioning

confidence: 98%

A comparative study of the physicochemical properties of perfluorinated and hydrogenated amphiphiles

Blanco

González‐Pérez

Ruso

et al. 2005

Journal of Colloid and Interface Science

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“…The same approach is much harder to achieve in gases, not least of all because it is difficult to find gases with small molecules that have very low solubility in water. One example of such low solubility gases are C n F m based perfluorocarbon gases, 7 often used as ultrasound contrast agents. 8 However,…”

Section: Introductionmentioning

confidence: 99%

Effect of particle adsorption rates on the disproportionation process in pickering stabilised bubbles

Ettelaie

Murray

2014

The Journal of Chemical Physics

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The degree of shrinkage of particle stabilised bubbles of various sizes, in a polydisperse bubble dispersion, has been investigated in the light of the finite adsorption times for the particles and the disproportionation kinetics of the bubbles. For the case where the system contains an abundance of particles we find a threshold radius, above which bubbles are stabilised without any significant reduction in their size. Bubbles with an initial radius below this threshold on the other hand, undergo a large degree of shrinkage prior to stabilisation.As the ratio of the available particles to the bubbles is reduced, it is shown that the final bubble size, for the larger bubbles in the distribution, becomes increasingly governed by the number of particles, rather than their adsorption time per se. For systems with "adsorption controlled" shrinkage ratio, the final bubble distribution is found to be wider than the initial one, while for a "particle number controlled" case it is actually narrower. Starting from an unimodal bubble size distribution, we predict that at intermediate times, prior to the full stabilisation of all bubbles, the distribution breaks up into a bimodal one. However, the effect is transient and an unimodal final bubble size distribution is recovered once again, when all the bubbles are stabilised by the particles.-3-1

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“…The computed difference in hydration free energy between perfluorooctane and n-octane is 2.54 AE 0.13 kcal∕mol (ΔU ¼ −5.46 AE 0.53 kcal∕mol, −TΔS ¼ 8.0 AE 0.58 kcal∕mol). From data at 298.16 K and 1 atm for methane (16), ethane (17), propane (18), and for perfluoromethane, perfluoroethane, and perfluoropropane (19) we have, for the cases C1, C2, C3, ΔF ¼ 1.13, 2.01, 2.85 kcal∕mol, respectively, which fitting to a polynomial form gives a rough estimate of ΔFðC8Þ ¼ 6.48 kcal∕mol. Our simulation results appear to underpredict the value implied by these experiments, similar to ΔFðC1Þ ¼ 0.44 kcal∕mol calculated by Gough et al (1).…”

mentioning

confidence: 99%

Molecular origins of fluorocarbon hydrophobicity

Dalvi

Rossky²

2010

Proc. Natl. Acad. Sci. U.S.A.

357

281

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We have undertaken atomistic molecular simulations to systematically determine the structural contributions to the hydrophobicity of fluorinated solutes and surfaces compared to the corresponding hydrocarbon, yielding a unified explanation for these phenomena. We have transformed a short chain alkane, n-octane, to n-perfluorooctane in stages. The free-energy changes and the entropic components calculated for each transformation stage yield considerable insight into the relevant physics. To evaluate the effect of a surface, we have also conducted contact-angle simulations of water on self-assembled monolayers of hydrocarbon and fluorocarbon thiols. Our results, which are consistent with experimental observations, indicate that the hydrophobicity of the fluorocarbon, whether the interaction with water is as solute or as surface, is due to its "fatness." In solution, the extra work of cavity formation to accommodate a fluorocarbon, compared to a hydrocarbon, is not offset by enhanced energetic interactions with water. The enhanced hydrophobicity of fluorinated surfaces arises because fluorocarbons pack less densely on surfaces leading to poorer van der Waals interactions with water. We find that interaction of water with a hydrophobic solute/surface is primarily a function of van der Waals interactions and is substantially independent of electrostatic interactions. This independence is primarily due to the strong tendency of water at room temperature to maintain its hydrogen bonding network structure at an interface lacking hydrophilic sites.solubility | hydration | wetting P erfluorinated alkanes which have all the hydrogen (H) atoms of an alkane replaced with fluorine (F) atoms are known to have much lower water solubilities than the corresponding hydrocarbons (1, 2) while at the same time showing high lipophobicity (2) and an extraordinary affinity for carbon dioxide (3, 4). Enzyme inhibitors with fluorinated moieties show stronger binding than their nonfluorinated analogues (5), even in cases when the group on the inhibitor is not among those that bind to the active site (6)-consistent with the expectation from higher hydrophobicity. One intriguing observation regarding the greater hydrophobicity is that the free energy of hydration per unit hydrophobic surface area is similar for hydrocarbons and fluorocarbons (6). The puzzling aspect of this similarity is that, because the C-F bond has a much greater dipole moment than does the C-H bond, a stronger binding with dipolar water might be expected. Further, although the polarizability of F in the C-F bond is relatively low considering its position in the periodic table, it is not lower than that in the C-H bond (7), so that the dispersion interactions of C-F with water are reasonably expected to be more attractive than those of C-H with water. Therefore, a fluorocarbon surface could be argued to be more hydrophilic than that of the corresponding hydrocarbon. A plausible resolution could be that the fluorocarbon with a molecular cross-section of 28.3 Å 2 (8) occupi...

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Thermodynamics of some perfluorocarbon gases in water

Cited by 58 publications

References 49 publications

A comparative study of the physicochemical properties of perfluorinated and hydrogenated amphiphiles

A comparative study of the physicochemical properties of perfluorinated and hydrogenated amphiphiles

Effect of particle adsorption rates on the disproportionation process in pickering stabilised bubbles

Molecular origins of fluorocarbon hydrophobicity

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