Freezing and melting of methanol in a single cylindrical pore: Dynamical supercooling and vitrification of methanol

Morishige, Kunimitsu; Kawano, Keizi

doi:10.1063/1.481742

Cited by 57 publications

(65 citation statements)

References 22 publications

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“…Such depression of the phase transition temperatures has been reported in literature to be characteristic of confined molecules in porous materials. [711][712][713][714][715][716] Remarkably, IB solidified in a glassy state and in a crystalline form when confined in MCM-41 35 and MCM-41 116 , respectively. Authors attributed these two radically different behaviors to steric effects; that is, crystalline ibuprofen is a dimer with a total length of  26 Å so that pores of 116 Å diameters were large enough to allow nucleation of crystallites, whereas pores of 35 Å diameters, even if the dimer fitted inside, were exceedingly constrained, thus inducing a vitrification process.…”

Section: Interaction With Drugs and Natural Productsmentioning

confidence: 99%

Silica Surface Features and Their Role in the Adsorption of Biomolecules: Computational Modeling and Experiments

et al. 2013

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Section: Interaction With Drugs and Natural Productsmentioning

confidence: 99%

Silica Surface Features and Their Role in the Adsorption of Biomolecules: Computational Modeling and Experiments

et al. 2013

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“…17 Crystallisation of bulk methanol cannot be avoided at low temperature so that the glassy state is unreachable with usual quenching rates. However, a glass transition has been reported for methanol deposited on a cold substrate from its vapour phase.…”

Section: /33mentioning

confidence: 99%

“…15,16 Phase transitions of methanol confined in regular cylindrical pores of MCM-41 and SBA-15 silicates have been investigated by X-rays diffraction. 17 The freezing/melting behavior depends markedly upon the pore size, with different degrees of hysteresis and metastability. Within the pores of diameter lower than 78 Å, crystallization never occurs and the confined methanol ultimately vitrifies at about 100 K close to the value of the bulk glass transition temperature.…”

Section: Introductionmentioning

confidence: 99%

Structure of liquid and glassy methanol confined in cylindrical pores

Morineau

Guégan

Xia

et al. 2004

The Journal of Chemical Physics

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We present a neutron scattering analysis of the density and the static structure factor of confined methanol at various temperatures. Confinement is performed in the cylindrical pores of MCM-41 silicates with pore diameters D=24 Å and D=35 Å. A change of the thermal expansivity of confined methanol at low temperature is the signature of a glass transition, which occurs at higher temperature for the smallest pore. This is an evidence of a surface induced slowing down of the dynamics of the fluid. The structure factor presents a systematic evolution with the pore diameter, which has been analyzed in terms of excluded volume effects and fluid-matrix cross-correlation. Conversely to the case of Van der Waals fluids, it shows that stronger fluid-matrix correlations must be invoked most probably in relation with the H-bonding character of both methanol and silicate surface. 2/33

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“…We know from theory of phase transitions (24) and experimental observations (25) that freezing of a liquid (or in fact any first-order phases transition) is rounded in a microscopic cylindrical (onedimensional) pore and the phase change becomes more obscure as the diameter decreases. In nanopores, however, freezing behavior is not simply explained by the general ''rounded-off'' picture but differs from one system to another and can be much richer than that in larger pores (18,26). An earlier MD simulation study showed that water in carbon nanotubes may freeze either continuously or discontinuously, depending on diameter and pressure (11).…”

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confidence: 99%

Phase diagram of water in carbon nanotubes

Takaiwa

Hatano

Koga

et al. 2008

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

323

351

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A phase diagram of water in single-walled carbon nanotubes at atmospheric pressure is proposed, which summarizes ice structures and their melting points as a function of the tube diameter up to 1.7 nm. The investigation is based on extensive molecular dynamics simulations over numerous thermodynamic states on the temperature-diameter plane. Spontaneous freezing of water in the simulations and the analysis of ice structures at 0 K suggest that there exist at least nine ice phases in the cylindrical space, including those reported by x-ray diffraction studies and those unreported by simulation or experiment. Each ice has a structure that maximizes the number of hydrogen bonds under the cylindrical confinement. The results show that the melting curve has many local maxima, each corresponding to the highest melting point for each ice form. The global maximum in the melting curve is located at Ϸ11 Å, where water freezes in a square ice nanotube.ice ͉ nanopore ͉ melting point W ater in well characterized pores is a system of general interest because it serves as model systems for ''nonbulk'' or inhomogeneous water ubiquitous in biological (1) and geological (2, 3) systems as well as in nanostructured materials (4). Studies of such nonbulk water are of fundamental importance because it is believed that confined or interfacial water is highly relevant to properties and functions of the entire systems, e.g., those of ion channels (1) and clay minerals (2). X-ray diffraction studies (5, 6) show that water can fill inner space of open-ended single-walled carbon nanotubes (SWNTs) at ambient conditions and freezes into crystalline solids often referred to as ''ice nanotubes.'' The ice structures are characterized as stacked n-membered rings or equivalently as a rolled square-net sheet (7). The formation of the ice nanotubes in carbon nanotubes has also been observed by NMR (8), neutron diffraction (9), and vibrational spectroscopy (10) studies. A prediction of the spontaneous ice formation in carbon nanotubes was made in a molecular dynamics (MD) simulation study (11). It was shown that the confined water freezes into square, pentagonal, hexagonal, and heptagonal ice nanotubes, and unexpectedly it does so either continuously (unlike any bulk substances, including bulk water) or discontinuously (despite of the fact that it is essentially in one dimension), depending on the diameter of carbon nanotubes or the applied pressure. Recent simulation studies predicted spontaneous formations of octagonal ice nanotubes (10, 12), ice nanotubes with hydrophobic guest molecules (13), single-layer helical ice sheets (14), and multiwalled ice helices and ice nanotubes (15)(16)(17). The versatility of ice we know for bulk water seems to survive in the nano confinement.Of the properties of water in the well defined nanopores, a fundamental yet little known aspect is a global picture of the phase behavior: we do not know pore-size dependence of the melting point in the nanometer scale or conditions for gradual and abrupt freezing. Previous re...

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Freezing and melting of methanol in a single cylindrical pore: Dynamical supercooling and vitrification of methanol

Cited by 57 publications

References 22 publications

Silica Surface Features and Their Role in the Adsorption of Biomolecules: Computational Modeling and Experiments

Silica Surface Features and Their Role in the Adsorption of Biomolecules: Computational Modeling and Experiments

Structure of liquid and glassy methanol confined in cylindrical pores

Phase diagram of water in carbon nanotubes

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