Hysteresis during isothermal scanning through the gas-liquid transition of carbon dioxide confined in nanometer pores

Wilkinson, N.J.; Duffy, J. A.; Fretwell, H. M.; Alam, M. A.

doi:10.1016/0375-9601(95)00475-i

Cited by 9 publications

(4 citation statements)

References 9 publications

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“…If the S-parameter is plotted (figure 3) a peak is seen in the second half of the melting transition, similar to that seen in our work on the gas-liquid transition [5,7]. There we found an enhancement in the pPs signature as the pores filled with liquid but not during emptying.…”

Section: Hysteresis At the Liquid-solid Boundarysupporting

confidence: 85%

“…The majority of our experiments [2,[4][5][6][7][8][9] have been performed using porous Vycor glass with interconnecting cylindrical pores of radius ∼20 Å and occupying ∼30% of the total sample volume. In these experiments, two porous Vycor glass samples were sandwiched around a 22 Na positron source (∼20-30 µCi) and inserted into the pressure cell [5,6].…”

Section: Methodsmentioning

confidence: 99%

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Positron and positronium annihilation studies of the phase behaviour of fluids in Vycor

Fretwell

Duffy

Clarke

et al. 1996

J. Phys.: Condens. Matter

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Section: Hysteresis At the Liquid-solid Boundarysupporting

confidence: 85%

Section: Methodsmentioning

confidence: 99%

Positron and positronium annihilation studies of the phase behaviour of fluids in Vycor

Fretwell

Duffy

Clarke

et al. 1996

J. Phys.: Condens. Matter

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“…The peak has disappeared by the time the pore condensation transition has finished (according to the N(3γ /2γ ) parameter). Such a signature has been seen before for CO 2 in Vycor [9,18] and has been attributed to the formation of microbubbles or large gas-liquid interfaces as the pores fill with liquid. We do not see such a feature in argon.…”

Section: Resultssupporting

confidence: 61%

Phase behaviour of argon and krypton adsorbed in mesoporous Vycor glass

Jones

Fretwell

2003

J. Phys.: Condens. Matter

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The phase behaviour of Ar and Kr adsorbed in Vycor glass at pressures and temperatures above the bulk triple point and below the bulk critical point has been investigated. Ar is found to condense in the pores ∼2 K above the bulk transition and freeze ∼10 K below the bulk transition. In contrast the condensation transition for Kr is shifted up by 4 K and freezing shifted down by 15 K. There is a pronounced hysteresis (4–6 K) at the liquid/solid phase boundary and a lesser amount (∼2 K) at the gas/liquid boundary. We find clear differences between the pore filling and emptying processes at the gas/liquid phase boundary and evidence of pore blocking on desorption. In addition microbubbles or large gas–liquid interfaces are thought to occur when Kr condenses in the pores but this effect is absent in Ar. Finally, solid Ar in the pores melts in a more continuous way than Kr.

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“…The positron/Ps annihilation with electrons of the filled gas molecules was not taken into account because the pore size is bigger than 50 nm. Previous studies 22,23 have shown that if the pores were filled with a gas, a larger fraction of the positrons would thermalize within them. Some of these positrons will annihilate as free positrons and some will form additional Ps.…”

Section: Introductionmentioning

confidence: 99%

A positron annihilation study on the microstructure of cyanate ester resin toughened by carboxyl‐terminated butadiene‐acrylonitrile rubber system

Zeng

Sun

Wang

et al. 2008

Polymers for Advanced Techs

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The toughness of cyanate ester (CE) resin matrix improves significantly with the addition of carboxyl-terminated butadiene-acrylonitrile rubber (CTBN). The curing behavior of the system was studied by differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The results show that carboxyl groups on the CTBN chain have a slight activation effect on the CE curing reaction at the beginning of the curing process. Phase separation was found to be the main toughening mechanism for CE/CTBN composites. The existence of macro-size pores induced by the decomposition of a small amount of the low weight molecular part of CTBN might be another toughening mechanism. It is confirmed that positron annihilation lifetime spectroscopy (PALS) is still valid in such a system where macropores filled with gas molecules exist. When a high weight percentage of CTBN (>8%) was added to CE, free-positron annihilation was found to be the dominant annihilation process in the macropores. For CTBN weight percentage higher than 8%, the contribution of ortho-positronium (o-Ps) annihilation in the macropores to t 3 and I 3 was found to be insignificant. It is effective to use PALS as a probe of free-volume properties in such systems by determining the changes in the t 3 and I 3 of the composite. The compatibility and interfacial adhesion of the composites can be estimated from the changes in the free-volume properties of the composites.

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Hysteresis during isothermal scanning through the gas-liquid transition of carbon dioxide confined in nanometer pores

Cited by 9 publications

References 9 publications

Positron and positronium annihilation studies of the phase behaviour of fluids in Vycor

Positron and positronium annihilation studies of the phase behaviour of fluids in Vycor

Phase behaviour of argon and krypton adsorbed in mesoporous Vycor glass

A positron annihilation study on the microstructure of cyanate ester resin toughened by carboxyl‐terminated butadiene‐acrylonitrile rubber system

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