Edge Contact Angle and Modified Kelvin Equation for Condensation in Open Pores.

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985858%3A_____%2F17%3A00482991" target="_blank" >RIV/67985858:_____/17:00482991 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/60461373:22340/17:43914989

Výsledek na webu

<a href="http://dx.doi.org/10.1103/PhysRevE.96.020801" target="_blank" >http://dx.doi.org/10.1103/PhysRevE.96.020801</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevE.96.020801" target="_blank" >10.1103/PhysRevE.96.020801</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Edge Contact Angle and Modified Kelvin Equation for Condensation in Open Pores.

Popis výsledku v původním jazyce

We consider capillary condensation transitions occurring in open slits of width L and finite height H immersed in a reservoir of vapor. In this case the pressure at which condensation occurs is closer to saturation compared to that occurring in an infinite slit (H = infinity) due to the presence of two menisci that are pinned near the open ends. Using macroscopic arguments, we derive a modified Kelvin equation for the pressure p(cc) (L, H) at which condensation occurs and show that the two menisci are characterized by an edge contact angle theta(e) that is always larger than the equilibrium contact angle theta, only equal to it in the limit of macroscopic H. For walls that are completely wet (theta = 0) the edge contact angle depends only on the aspect ratio of the capillary and is well described by theta e approximate to root pi L/2H for large H. Similar results apply for condensation in cylindrical pores of finite length. We test these predictions against numerical results obtained using a microscopic density-functional model where the presence of an edge contact angle characterizing the shape of the menisci is clearly visible from the density profiles. Below the wetting temperature T-w we find very good agreement for slit pores of widths of just a few tens of molecular diameters, while above T-w the modified Kelvin equation only becomes accurate for much larger systems.

Název v anglickém jazyce

Edge Contact Angle and Modified Kelvin Equation for Condensation in Open Pores.

Popis výsledku anglicky

We consider capillary condensation transitions occurring in open slits of width L and finite height H immersed in a reservoir of vapor. In this case the pressure at which condensation occurs is closer to saturation compared to that occurring in an infinite slit (H = infinity) due to the presence of two menisci that are pinned near the open ends. Using macroscopic arguments, we derive a modified Kelvin equation for the pressure p(cc) (L, H) at which condensation occurs and show that the two menisci are characterized by an edge contact angle theta(e) that is always larger than the equilibrium contact angle theta, only equal to it in the limit of macroscopic H. For walls that are completely wet (theta = 0) the edge contact angle depends only on the aspect ratio of the capillary and is well described by theta e approximate to root pi L/2H for large H. Similar results apply for condensation in cylindrical pores of finite length. We test these predictions against numerical results obtained using a microscopic density-functional model where the presence of an edge contact angle characterizing the shape of the menisci is clearly visible from the density profiles. Below the wetting temperature T-w we find very good agreement for slit pores of widths of just a few tens of molecular diameters, while above T-w the modified Kelvin equation only becomes accurate for much larger systems.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

<a href="/cs/project/GA17-25100S" target="_blank" >GA17-25100S: Geometricky a chemicky strukturované povrchy: od rovnováhy k dynamice</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review E

ISSN

2470-0045

e-ISSN

—

Svazek periodika

96

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

5

Strana od-do

—

Kód UT WoS článku

000406912000001

EID výsledku v databázi Scopus

2-s2.0-85028717468