Phase Transitions in Multimolecular Layers of Adsorbed Nitrogen

Morrison, J. A.; Drain, L. E.; Dugdale, J. S.

doi:10.1139/v52-108

Cited by 46 publications

(12 citation statements)

References 13 publications

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“…If this is true, one must consider here a solid meniscus with the appropriate forces, since both Antooniou (7) and Litvan (8) have shown that at -40 "6: all but two molecular layers (8.9 %) of adsorbed water are in a froze11 state. This has also beer, observed for other systems (11,12). The vertical portion BC of curves of this type has been attributed to the flattening of menisci (4).…”

Section: Methodssupporting

confidence: 62%

Length change – adsorption relations for the water – porous glass system to −40 °C

Feldman¹

1970

Can. J. Chem.

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Adsorption of water has been studied extensively above 0 "C, but the problem of the phase transition of adsorbates in porous materials is presented at temperatures below 0 "C. Experiments that show how phase transitions modify length change -adsorption relationships are described.Adsorption -length change measurements froin -40 to -0.5 and isotherms at -20 and -0.5 "C were obtained. In another group of experiments different forms of isosteres were also obtained; the principle that water should be allowed to enter the sample at the low temperature was usually followed.Isothernls and length change -adsorption characteristics below 0 "C are qualitatively similar to those above 0 "C, but a decrease in adsorptive capacity and length change was observed. These results and those obtained from the isosteres lead to the conclusion that capillary condensation and menisci theories are operative and that a solid meniscus exists. It follows therefore that the saturated vapor pressure of frozen adsorbate is greater than that of bulk ice and that its voli~metric expansion on freezing is similar to the bulk phase transition. It is shown how these phenomena can predict migration of water and generation of pressure within the porous body when it is subjected to cooling and warming cycles.

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Section: Methodssupporting

confidence: 62%

Length change – adsorption relations for the water – porous glass system to −40 °C

Feldman¹

1970

Can. J. Chem.

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“…As the cluster increases in size, typically 1) the solid becomes thermodynamically more stable and 2) the transition to convert the solid into a liquid becomes sharper. [99,100] Table 3 shows the case of increasing numbers of layers of N 2 molecules absorbed on a surface. [99] The physical basis for this effect is that as the assemblies increase in size, any given molecule within the solid has other molecules extending out to greater distances that help to hold it in place.…”

Section: The General Structural Consequences Of Positively Cooperativmentioning

confidence: 99%

Understanding Noncovalent Interactions: Ligand Binding Energy and Catalytic Efficiency from Ligand‐Induced Reductions in Motion within Receptors and Enzymes

et al. 2004

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Noncovalent interactions are sometimes treated as additive and this enables useful average binding energies for common interactions in aqueous solution to be derived. However, the additive approach is often not applicable, since noncovalent interactions are often either mutually reinforcing (positively cooperative) or mutually weakening (negatively cooperative). Ligand binding energy is derived (positively cooperative binding) when a ligand reduces motion within a receptor. Similarly, transition-state binding energy is derived in enzyme-catalyzed reactions when the substrate transition state reduces the motions within an enzyme. Ligands and substrates can in this way improve their affinities for these proteins. The further organization occurs with a benefit in bonding (enthalpy) and a limitation in dynamics (cost in entropy), but does not demand the making of new noncovalent interactions, simply the strengthening of existing ones. Negative cooperativity induces converse effects: less efficient packing, a cost in enthalpy, and a benefit in entropy.

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“…I t is renlarlcable that the \\-ater-glass system behaves siinilarly in this respect to the rutile-nitrogen ( 5 ) and rutile-argon (6) systems \\here the onset of freezing occurs after the coverage exceeds two layers.…”

Section: Absence Of Transitionmentioning

confidence: 99%

Phase Transitions of Adsorbates: 1. Specific Heat and Dimensional Changes of the Porous Glass – Water System

Litvan¹

1966

Can. J. Chem.

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'I'he specific heat and dimensior~al changes of the porous !)6yo silica glass -\\later s).stem n-ere measured simultaneously between -35 "C and +2 'C with coverages of 1.6, 4.0, 5.3, cuid '7.7 molecular layers. 'I'he specific heat of the adsorbate below the transition range was found to be higher than that of ice. Xo phase change was detected with the lowest concentration. At the higher coverages, transition always occurred near -0.5' a~l d was of the anomalous first order type. The values of the specific latent heat of fusion, calculated by assuming that. two monolayers do not freeze, are 40.4, 54.4, and 5S..i cal g-l, deperiding on the concentr;~tion. 'I'he correlation between the results of calorimetric and dimensional change measuretiielits 1v;is considered s;~tisfactory.

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Phase Transitions in Multimolecular Layers of Adsorbed Nitrogen

Cited by 46 publications

References 13 publications

Length change – adsorption relations for the water – porous glass system to −40 °C

Length change – adsorption relations for the water – porous glass system to −40 °C

Understanding Noncovalent Interactions: Ligand Binding Energy and Catalytic Efficiency from Ligand‐Induced Reductions in Motion within Receptors and Enzymes

Phase Transitions of Adsorbates: 1. Specific Heat and Dimensional Changes of the Porous Glass – Water System

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