Simplicity of supercooled liquids: Experimental investigations inspired by the isomorph theory

Publikation: Bog/antologi/afhandling/rapportPh.d.-afhandlingForskning

Resumé

Denne afhandling undersøger simpel opførsel af underafkølede væsker inspireret af isomorph teoriens forudsigelser for Roskilde-simple væsker. Van der Waals bundne væsker forventes at være Roskilde simple, mens hydrogen bundne væsker ikke er. Fire undersøgelser præsenteres.
1) En væske opfylder isochronal superposition, hvis dens dynamik er invariant langs en isokron. Vi udvikler kvantitative mål af isochronal superposition og
anvender dem på de fire van der Waals bundne væsker, polyphenyl ether, diethyl phthalate, tetramethyl tetraphenyl trisiloxane, og dibutyl phthalate, og de to hydrogen bundne væsker, glycerol og 1,2,6 hexanetriol. Vi konkluderer, at van der Waals væskerne har isochronal superposition i større grad end de hydrogenbundne væsker. Dette bekræfter en forudsigelse fra isomorph teorien.
2) Vi undersøger den frekvensafhængige varmefylde ved høje tryk for den van der Waals bundne væske, polyphenyl ether. Resultaterne sammenlignes med lignende dielektriske resultater for at teste om isokronerne for de to metoder er
sammenfaldende. Vi konkluderer, at forholdet mellem de karakteristiske tider er uafhængigt af både temperatur og tryk, hvilket er en simplere opførsel end forudsagt af isomorph teorien.
3) "Aging"-opførslen efterfulgt af temperatur ændringer undersøges for de hydrogen bundne væsker, glycerol og 1,2,6 hexanetriol, og den van der Waals
bundne væske, diethyl phthalate. To tests af "én"-parameter aging (den målte størrelse og raten kontrolleres af den samme parameter) generaliseres. Vi
konkluderer, at alle de undersøgte væsker har tilnærmelsesvis "én"-parameter
aging.
4) Isomorph teorien forudsiger, at Roskilde-simple væsker kommer instantant i ligevægt efter et spring fra et punkt på en isokron til et andet punkt på den
samme isokron. Vores foreløbige målinger på den van der Waals bundne væske polyphenyl ether bekræfter denne forudsigelse.
Den samlede konklusion er, at de van der Waals bundne væsker følger forudsigelserne fra isomorph teorien, og at nogle af dem har endnu simplere
opførsel. De hydrogen bundne væsker har også tilnærmelsesvis simpel opførsel.
OriginalsprogEngelsk
Udgivelses stedRoskilde
ForlagRoskilde Universitet
Antal sider203
StatusUdgivet - 31 okt. 2018

Citer dette

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title = "Simplicity of supercooled liquids: Experimental investigations inspired by the isomorph theory",
abstract = "This thesis investigates simple behavior of supercooled liquids inspired by theisomorph theory’s predictions for Roskilde-simple liquids. Van der Waals liquidsare expected to be Roskilde simple, whereas hydrogen-bonded liquids are not.Four investigations are presented.1) A liquid obeys isochronal superposition if its dynamics is invariant alongthe isochrones. We develop quantitative measures of isochronal superpositionand use them on the four van derWaals-bonded liquids, polyphenyl ether, diethylphthalate, tetramethyl tetraphenyl trisiloxane, and dibutyl phthalate, and thetwo hydrogen-bonded liquids, glycerol and 1,2,6 hexanetriol. We conclude thatthe van der Waals liquids obey isochronal superposition to a higher degree thanthe hydrogen-bonded liquids. This confirms a prediction of the isomorph theory.2) The van der Waals-bonded liquid, polyphenyl ether, is studied usingspecific heat spectroscopy under high pressure. The results are compared tosimilar dielectric results to test if the isochrones from the two methods coincide.We conclude that the ratio between the two time scales is independent of bothtemperature and pressure, which is a greater simplicity than predicted by theisomorph theory.3) Aging following jumps in temperature is studied for the hydrogen-bondedliquids, glycerol and 1,2,6 hexanetriol, and the van der Waals-bonded liquid,diethyl phthalate. Two tests of single-parameter aging (the measured quantityand the clock rate are controlled by the same parameter) are generalized.We conclude that all studied liquids have single-parameter aging to a goodapproximation.4) The isomorph theory predicts that Roskilde-simple liquids come intoinstantaneous equilibrium following a jump from a state point on an isochroneto another state point on the same isochrone. Our preliminary measurementson the van der Waals-bonded liquid, polyphenyl ether, confirms this prediction.As an overall conclusion, the van der Waals liquids follow the predictionsfrom the isomorph theory, with several of the liquids showing even greatersimplicity. The hydrogen-bonded liquids also have simple behavior to a goodapproximation.",
author = "Schmidt, {Lisa Anita Roed}",
year = "2018",
month = "10",
day = "31",
language = "English",
publisher = "Roskilde Universitet",

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Simplicity of supercooled liquids : Experimental investigations inspired by the isomorph theory. / Schmidt, Lisa Anita Roed.

Roskilde : Roskilde Universitet, 2018. 203 s.

Publikation: Bog/antologi/afhandling/rapportPh.d.-afhandlingForskning

TY - BOOK

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T2 - Experimental investigations inspired by the isomorph theory

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PY - 2018/10/31

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N2 - This thesis investigates simple behavior of supercooled liquids inspired by theisomorph theory’s predictions for Roskilde-simple liquids. Van der Waals liquidsare expected to be Roskilde simple, whereas hydrogen-bonded liquids are not.Four investigations are presented.1) A liquid obeys isochronal superposition if its dynamics is invariant alongthe isochrones. We develop quantitative measures of isochronal superpositionand use them on the four van derWaals-bonded liquids, polyphenyl ether, diethylphthalate, tetramethyl tetraphenyl trisiloxane, and dibutyl phthalate, and thetwo hydrogen-bonded liquids, glycerol and 1,2,6 hexanetriol. We conclude thatthe van der Waals liquids obey isochronal superposition to a higher degree thanthe hydrogen-bonded liquids. This confirms a prediction of the isomorph theory.2) The van der Waals-bonded liquid, polyphenyl ether, is studied usingspecific heat spectroscopy under high pressure. The results are compared tosimilar dielectric results to test if the isochrones from the two methods coincide.We conclude that the ratio between the two time scales is independent of bothtemperature and pressure, which is a greater simplicity than predicted by theisomorph theory.3) Aging following jumps in temperature is studied for the hydrogen-bondedliquids, glycerol and 1,2,6 hexanetriol, and the van der Waals-bonded liquid,diethyl phthalate. Two tests of single-parameter aging (the measured quantityand the clock rate are controlled by the same parameter) are generalized.We conclude that all studied liquids have single-parameter aging to a goodapproximation.4) The isomorph theory predicts that Roskilde-simple liquids come intoinstantaneous equilibrium following a jump from a state point on an isochroneto another state point on the same isochrone. Our preliminary measurementson the van der Waals-bonded liquid, polyphenyl ether, confirms this prediction.As an overall conclusion, the van der Waals liquids follow the predictionsfrom the isomorph theory, with several of the liquids showing even greatersimplicity. The hydrogen-bonded liquids also have simple behavior to a goodapproximation.

AB - This thesis investigates simple behavior of supercooled liquids inspired by theisomorph theory’s predictions for Roskilde-simple liquids. Van der Waals liquidsare expected to be Roskilde simple, whereas hydrogen-bonded liquids are not.Four investigations are presented.1) A liquid obeys isochronal superposition if its dynamics is invariant alongthe isochrones. We develop quantitative measures of isochronal superpositionand use them on the four van derWaals-bonded liquids, polyphenyl ether, diethylphthalate, tetramethyl tetraphenyl trisiloxane, and dibutyl phthalate, and thetwo hydrogen-bonded liquids, glycerol and 1,2,6 hexanetriol. We conclude thatthe van der Waals liquids obey isochronal superposition to a higher degree thanthe hydrogen-bonded liquids. This confirms a prediction of the isomorph theory.2) The van der Waals-bonded liquid, polyphenyl ether, is studied usingspecific heat spectroscopy under high pressure. The results are compared tosimilar dielectric results to test if the isochrones from the two methods coincide.We conclude that the ratio between the two time scales is independent of bothtemperature and pressure, which is a greater simplicity than predicted by theisomorph theory.3) Aging following jumps in temperature is studied for the hydrogen-bondedliquids, glycerol and 1,2,6 hexanetriol, and the van der Waals-bonded liquid,diethyl phthalate. Two tests of single-parameter aging (the measured quantityand the clock rate are controlled by the same parameter) are generalized.We conclude that all studied liquids have single-parameter aging to a goodapproximation.4) The isomorph theory predicts that Roskilde-simple liquids come intoinstantaneous equilibrium following a jump from a state point on an isochroneto another state point on the same isochrone. Our preliminary measurementson the van der Waals-bonded liquid, polyphenyl ether, confirms this prediction.As an overall conclusion, the van der Waals liquids follow the predictionsfrom the isomorph theory, with several of the liquids showing even greatersimplicity. The hydrogen-bonded liquids also have simple behavior to a goodapproximation.

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PB - Roskilde Universitet

CY - Roskilde

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