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Mugele, Friedrich Gunther; Persson, B. N. J.; Zilberman, S.; Nitzan, Abraham; Salmerón, Miquel

doi:10.1023/a:1014022406110

Cited by 17 publications

(18 citation statements)

References 25 publications

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“…On the other hand, we would not expect such an increase in T f for water in these materials since R is smaller than 1. 11,12 Recent SFA experiments have confirmed this prediction by showing that water 23,24 and some alcohols (octanol, undecanol 25 ) remain fluid-like, even for confined film thicknesses below 1 nm.…”

Section: Introductionmentioning

confidence: 90%

Effect of Pressure on the Freezing of Pure Fluids and Mixtures Confined in Nanopores

et al. 2009

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Monte Carlo simulations combined with the parallel tempering technique are used to study the freezing of Ar, CH 4 , and their mixtures in a slit graphite nanopore. For all systems, the solid/liquid coexistence line is located at higher temperature than that for the bulk phase, as expected for fluids for which the wall/fluid interaction is stronger than the fluid/fluid interaction. In the case of the mixtures, the phase diagram for the confined system is of the same type as that for the bulk (azeotropic). It is also found that the freezing temperatures for the confined fluids and mixture are much more affected by pressure than those for the bulk phase. By calculating the isothermal compressibility of the confined fluids and determining the slope of the solid/liquid coexistence line (T,P) from the Clapeyron equation, we show that such a strong effect of pressure is not related to reduced compressibility within the pores. On the other hand, the pressure dependence of the in-pore freezing temperature is correctly described in the frame of the model proposed by Miyahara et al.[Miyahara, M.; Kanda, H.; Shibao, M.; Higashitani, K. J. Chem. Phys. 2000, 112, 9909.], which is based on the pressure difference between the bulk and confined phases (capillary effect). In this model, a change in the in-pore freezing temperature with pressure is explained by a drastic change in the in-pore pressure, which varies very sharply with the bulk external pressure. We present an extended version of this model to confined systems for which an increase in the freezing temperature is observed.

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Section: Introductionmentioning

confidence: 90%

Effect of Pressure on the Freezing of Pure Fluids and Mixtures Confined in Nanopores

et al. 2009

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“…For some polymer–polymer sliding combinations, however, the associated wear is prohibitively high; this is especially true for PTFE. , One approach to addressing the issue of excessive PTFE wear involves the use of confined molecules between the two self-mated polymer surfaces. A number of fundamental studies − have been conducted to explain the complex relationships among contact pressure, number of monolayers, and viscosity to the mechanical and frictional responses to shear stress, as well as to characterize the nature of layering dynamics and relaxation times. Here, a more phenomenological approach is taken, and confined fluorocarbon molecules of varying lengths are compressed and sheared between two individually cross-linked PTFE surfaces.…”

Section: Introductionmentioning

confidence: 99%

Effect of Fluorocarbon Molecules Confined between Sliding Self-Mated PTFE Surfaces

et al. 2011

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We report on the frictional response and atomic process that occur when molecular fluorocarbon molecules of varying lengths are sheared between two polytetrafluoroethylene (PTFE) surfaces. The thicknesses of the molecular layers are also varied. The approach is classical molecular dynamics simulations using a reactive bond-order potential parametrized for fluorocarbons. The results indicate that the presence of the molecules has a significant impact on the measured friction and wear of the surfaces, and that this impact depends on the nature of the fluorocarbon molecules and the thickness of the molecular film. The molecular mechanisms responsible for these differences are presented.

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“…This was interpreted as a liquid to solid phase transition occurring at temperatures well above the bulk freezing point. In addition, a number of experiments using activated carbon fibers (ACF) have reported that the freezing temperature in confinement may be lower (water, [29][30][31] octanol 32 and undecanol 32 ) or higher (methanol, 31 carbon tetrachloride, 33 benzene, 34 aniline, 35 OMCTS 36 and cyclohexane 36 ) than the bulk value; in some cases (nitrobenzene 37 ), no appreciable change in the freezing temperature was observed.…”

Section: Introductionmentioning

confidence: 99%

An experimental study of melting of CCl4 in carbon nanotubes

Jażdżewska

Hung

Gubbins

et al. 2005

Phys. Chem. Chem. Phys.

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We report dielectric relaxation spectroscopy measurements of the melting point of carbon tetrachloride confined within open-tip multi-walled carbon nanotubes with two different pore diameters, 4.0 and 2.8 nm. In both cases, a single transition temperature well above the bulk melting point was obtained for confined CCl4. These results contrast with what was obtained in our previous measurements using carbon nanotubes with a pore diameter of 5.0 nm, where multiple transition temperatures both above and below the bulk melting point of CCl4 were observed. Our experimental measurements are consistent with our recent molecular simulation results (F. R. Hung, B. Coasne, E. E. Santiso, K. E. Gubbins, F. R. Siperstein and M. Sliwinska-Bartkowiak, J. Chem. Phys., 2005, 122, 144706). Although the simulations overestimate the temperatures in which melting upon confinement occurs, both simulations and experiments suggest that all regions of adsorbate freeze at the same temperature, and that freezing occurs at higher temperatures upon reduction of the pore diameter.

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Cited by 17 publications

References 25 publications

Effect of Pressure on the Freezing of Pure Fluids and Mixtures Confined in Nanopores

Effect of Pressure on the Freezing of Pure Fluids and Mixtures Confined in Nanopores

Effect of Fluorocarbon Molecules Confined between Sliding Self-Mated PTFE Surfaces

An experimental study of melting of CCl4 in carbon nanotubes

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