On the phase diagram of polymorphic ethanol: Thermodynamic and structural studies

Ramos, M. A.; Шмытько, И. М.; Arnautova, E. A.; Riobóo, R. J. Jiménez; ́guez-Mora, V. Rodrı; Vieira, S.; Capitán, M. J.

doi:10.1016/j.jnoncrysol.2006.02.143

Cited by 46 publications

(58 citation statements)

References 18 publications

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“…Diffraction spectra of the obtained monoclinic phase are close to that described in [1,4]. They differ a bit for various temperatures of annealing and for samples obtained from "gel" and by direct quick freezing.…”

Section: X-ray Measurementssupporting

confidence: 76%

“…The gel was prepared via condensation of a gas mixture of ethanol vapor and 4 He on the surface of superfluid helium He II cooled below 1.8 K. The samples were prepared in situ for subsequent studies by small-angle neutron scattering (SANS) at liquid helium temperatures in a special cryostat [18]. Initially the sample of the deuterated ethanol gel was prepared in the cell installed in the middle part of the cryostat [19], where we placed a pair of windows for visual control of the sample formation inside the quartz cell.…”

Section: Preparation Of Ethanol-helium "Gel" Samplesmentioning

confidence: 99%

“…The stable orientational ordered crystal of monoclinic phase was produced via very slow growth of the sample at a temperature close to the melting point. There are a lot of measurements of different type with ethanol samples: x-ray diffraction [1][2][3][4], Raman spectroscopy [2], specific heat [3,[5][6][7][8][9][10], complex dielectric susceptibility [11], neutron scattering [3,5,12], thermal conductivity [13], light and infrared reflection [14,15]. In fact, the most evident experimental result is the existence of the stable monoclinic crystalline phase at the temperature close to melting [1] (fully ordered structure) and the amorphous state (glass like state, supercooled liquid and so on) in a completely disordered phase, which was formed by quenching faster than 30 K/min [16].…”

Section: Introductionmentioning

confidence: 99%

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Structural and phase transitions in nanocluster ethanol samples at low temperatures

Ефимов

Izotov

Межов-Деглин

et al. 2015

Low Temperature Physics

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Results of neutron (SANS study) and x-ray diffraction experiments with nanocluster samples of deuteroethanol (C 2 D 5 OD) or ordinary pure ethanol (C 2 H 5 OH) are presented. A deuterated ethanol sample, formed via quick cooling of ethanol-helium mixture down to 1.6 K, had clusters with the size of d ~ 20-30 nm at liquid helium temperatures. After warming up to liquid nitrogen temperatures the gel decays into an amorphous white powder. It was observed that these powder samples remained in the amorphous state even after keeping at T ≤ 90 K for a long time (a few months). The neutron studies were supported by further x-ray investigations of the structure and the phase transitions in the highly dispersed powder samples, which were created via the decay of the gel samples of ordinary ethanol at temperatures above liquid nitrogen up to 150 K at saturated nitrogen gas pressure. Annealing of the "gel" sample during half an hour at a temperature of T ~ 110 K resulted in a phase transition to a monoclinic phase with the crystallite sizes ~30-40 nm. For comparison we studied the structure and phase transitions in "bulk" samples, prepared via quick freezing of liquid ethanol down to liquid nitrogen temperature. The "bulk" sample had a similar transition at T ~ 125 K, which is by 15 K higher than the temperature of the intensive phase transition in the "gel" sample. The mean grain size in the bulk material was d ≥ 60 nm.

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Section: X-ray Measurementssupporting

confidence: 76%

Section: Preparation Of Ethanol-helium "Gel" Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Structural and phase transitions in nanocluster ethanol samples at low temperatures

Ефимов

Izotov

Межов-Деглин

et al. 2015

Low Temperature Physics

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“…As described in more detail elsewhere, 39,45 we have implemented a calorimetric system for glass-forming liquids that allows in situ preparation and calorimetric characterization of the different phases of the substance (typically using liquid nitrogen as thermal sink), followed by accurate heat-capacity measurements at low temperatures, where the liquid-nitrogen bath is readily replaced by liquid helium, using two alternative thermal relaxation methods. The thermal conductivity of the different position isomers of butanol was measured under equilibrium vapor pressure in an experimental setup already described, 46 using the steadystate potentiometric method.…”

Section: Experimental Techniques and Materialsmentioning

confidence: 99%

“…27 In particular, glass-forming molecular liquids are interesting and appealing model systems to investigate the universal low-temperature properties of glasses, since they often allow one to control several key variables such as comparing different isotopic compositions [29][30][31] or different isomers for the same substance, 30,[32][33][34] or using the existence of polymorphism to critically compare phases with different kinds of disorder. [35][36][37][38][39] In addition, these molecular liquids offer an easy and convenient temperature range to explore liquid-solid phase transitions such as the glass transition, and other relaxational processes. [40][41][42][43][44] In this work we have conducted experiments at low temperatures with the four position isomers (also called chemical or structural isomers) of butanol, though in only three of them were we able to obtain the glass state.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature thermal and elastoacoustic properties of butanol glasses: Study of position isomerism effects around the boson peak

et al. 2012

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We have concurrently measured the specific heat, the thermal conductivity, and the longitudinal and transverse sound velocities at low temperature of glasses from different isomers of butanol (n-butanol, sec-butanol and isobutanol), as well as the low-temperature specific heat for the crystals of n-butanol, isobutanol and tert-butanol. Whereas the elastic constants both for crystals and glasses are found to be almost independent of the position of the hydrogen bonds, the thermal properties at low temperatures of these glasses at a few kelvin (around the boson peak in the reduced specific heat or around the plateau in the thermal conductivity) are found to vary strongly. Our experiments clearly contradict other works or models claiming a Debye scaling of the boson peak, and hence of the excess low-temperature specific heat of glasses. Data analysis based upon the soft-potential model and its extensions allows us to estimate the Ioffe-Regel limit in these and other alcohol glasses, finding a correlation with the boson-peak position in agreement with that previously reported by other groups.

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Calorimetric studies at low temperatures of glass‐forming 1‐butanol and 2‐butanol

Hassaine¹,

Ramos²

2011

Physica Status Solidi (a)

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We present calorimetric experiments and specific‐heat Cp(T) measurements of 1‐butanol (n‐butanol) and of one of its chemical isomers, the secondary alcohol 2‐butanol (sec‐butanol), around its glass transition Tg as well as at low temperatures (1.6–30 K). We have obtained and measured both the glass and crystalline states of 1‐butanol, and the glass state of 2‐butanol which is an even better glass former. In this work, we focus on the comparative study of the calorimetric or thermodynamic properties of the glassy states of these two isomers of butanol, determining their glass‐transition temperatures, their discontinuities in specific heat at Tg, and the corresponding enthalpy fictive temperatures. At temperatures below 10 K, both isomers present the typical broad maximum for glasses in Cp/T3, often called the boson peak, its magnitude being much larger in 2‐butanol than in 1‐butanol.

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On the phase diagram of polymorphic ethanol: Thermodynamic and structural studies

Cited by 46 publications

References 18 publications

Structural and phase transitions in nanocluster ethanol samples at low temperatures

Structural and phase transitions in nanocluster ethanol samples at low temperatures

Low-temperature thermal and elastoacoustic properties of butanol glasses: Study of position isomerism effects around the boson peak

Calorimetric studies at low temperatures of glass‐forming 1‐butanol and 2‐butanol

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