Impact of thickness on CO2 concentration profiles within polymer films swollen near the critical pressure

Xinxin Li, Bryan Vogt

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The isothermal swelling of polymer thin films by a supercritical fluid does not increase monotonically with increasing chemical potential (pressure), but rather a maximum in swelling is generally observed near the critical pressure. A reactive templating approach utilizing the condensation of silica within hydrophilic domains of a swollen amphiphilic polymer film enables visualization of the qualitative concentration profile of CO2 by the changes in the size of hydrophobic domains (pores) with cross sectional TEM microscopy; specifically, isothermal swelling of poly(ethylene oxide-propylene oxide-ethylene oxide) films by CO2 at 60 °C is examined. Films that contain thickness gradients are used to avoid any uncertainties in the impact of thickness due to variations in the temperature or pressure during the silica modification. A uniform pore size (local swelling) is observed for all film thicknesses when the pressure is outside of the anomalous maximum in the film swelling, except for a small increase at the buried interface due to preferential adsorption of CO2 to the native silicon oxide surface of the substrate. However at this swelling maximum, a gradient in the pore size is observed at both interfaces. These swelling gradients at interfaces appear to be responsible for the anomalous maximum in thin films. As the film thickness increases beyond 350 nm, there is a decrease in the maximum swelling at the free interface.

Original languageEnglish (US)
Pages (from-to)4182-4188
Number of pages7
JournalPolymer
Volume50
Issue number17
DOIs
StatePublished - Aug 12 2009

Fingerprint

Polymer films
Swelling
Silicon Dioxide
Pore size
Film thickness
Silica
Ethylene Oxide
Thin films
Supercritical fluids
Chemical potential
Silicon oxides
Polyethylene oxides
Oxide films
Propylene
Condensation
Microscopic examination
Ethylene
Visualization
Transmission electron microscopy
Adsorption

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

Cite this

@article{e61bfeef65ce43a694c48a4f74c7e50e,
title = "Impact of thickness on CO2 concentration profiles within polymer films swollen near the critical pressure",
abstract = "The isothermal swelling of polymer thin films by a supercritical fluid does not increase monotonically with increasing chemical potential (pressure), but rather a maximum in swelling is generally observed near the critical pressure. A reactive templating approach utilizing the condensation of silica within hydrophilic domains of a swollen amphiphilic polymer film enables visualization of the qualitative concentration profile of CO2 by the changes in the size of hydrophobic domains (pores) with cross sectional TEM microscopy; specifically, isothermal swelling of poly(ethylene oxide-propylene oxide-ethylene oxide) films by CO2 at 60 °C is examined. Films that contain thickness gradients are used to avoid any uncertainties in the impact of thickness due to variations in the temperature or pressure during the silica modification. A uniform pore size (local swelling) is observed for all film thicknesses when the pressure is outside of the anomalous maximum in the film swelling, except for a small increase at the buried interface due to preferential adsorption of CO2 to the native silicon oxide surface of the substrate. However at this swelling maximum, a gradient in the pore size is observed at both interfaces. These swelling gradients at interfaces appear to be responsible for the anomalous maximum in thin films. As the film thickness increases beyond 350 nm, there is a decrease in the maximum swelling at the free interface.",
author = "Xinxin Li and Bryan Vogt",
year = "2009",
month = "8",
day = "12",
doi = "10.1016/j.polymer.2009.06.069",
language = "English (US)",
volume = "50",
pages = "4182--4188",
journal = "Polymer",
issn = "0032-3861",
publisher = "Elsevier BV",
number = "17",

}

Impact of thickness on CO2 concentration profiles within polymer films swollen near the critical pressure. / Li, Xinxin; Vogt, Bryan.

In: Polymer, Vol. 50, No. 17, 12.08.2009, p. 4182-4188.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Impact of thickness on CO2 concentration profiles within polymer films swollen near the critical pressure

AU - Li, Xinxin

AU - Vogt, Bryan

PY - 2009/8/12

Y1 - 2009/8/12

N2 - The isothermal swelling of polymer thin films by a supercritical fluid does not increase monotonically with increasing chemical potential (pressure), but rather a maximum in swelling is generally observed near the critical pressure. A reactive templating approach utilizing the condensation of silica within hydrophilic domains of a swollen amphiphilic polymer film enables visualization of the qualitative concentration profile of CO2 by the changes in the size of hydrophobic domains (pores) with cross sectional TEM microscopy; specifically, isothermal swelling of poly(ethylene oxide-propylene oxide-ethylene oxide) films by CO2 at 60 °C is examined. Films that contain thickness gradients are used to avoid any uncertainties in the impact of thickness due to variations in the temperature or pressure during the silica modification. A uniform pore size (local swelling) is observed for all film thicknesses when the pressure is outside of the anomalous maximum in the film swelling, except for a small increase at the buried interface due to preferential adsorption of CO2 to the native silicon oxide surface of the substrate. However at this swelling maximum, a gradient in the pore size is observed at both interfaces. These swelling gradients at interfaces appear to be responsible for the anomalous maximum in thin films. As the film thickness increases beyond 350 nm, there is a decrease in the maximum swelling at the free interface.

AB - The isothermal swelling of polymer thin films by a supercritical fluid does not increase monotonically with increasing chemical potential (pressure), but rather a maximum in swelling is generally observed near the critical pressure. A reactive templating approach utilizing the condensation of silica within hydrophilic domains of a swollen amphiphilic polymer film enables visualization of the qualitative concentration profile of CO2 by the changes in the size of hydrophobic domains (pores) with cross sectional TEM microscopy; specifically, isothermal swelling of poly(ethylene oxide-propylene oxide-ethylene oxide) films by CO2 at 60 °C is examined. Films that contain thickness gradients are used to avoid any uncertainties in the impact of thickness due to variations in the temperature or pressure during the silica modification. A uniform pore size (local swelling) is observed for all film thicknesses when the pressure is outside of the anomalous maximum in the film swelling, except for a small increase at the buried interface due to preferential adsorption of CO2 to the native silicon oxide surface of the substrate. However at this swelling maximum, a gradient in the pore size is observed at both interfaces. These swelling gradients at interfaces appear to be responsible for the anomalous maximum in thin films. As the film thickness increases beyond 350 nm, there is a decrease in the maximum swelling at the free interface.

UR - http://www.scopus.com/inward/record.url?scp=67949097572&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=67949097572&partnerID=8YFLogxK

U2 - 10.1016/j.polymer.2009.06.069

DO - 10.1016/j.polymer.2009.06.069

M3 - Article

AN - SCOPUS:67949097572

VL - 50

SP - 4182

EP - 4188

JO - Polymer

JF - Polymer

SN - 0032-3861

IS - 17

ER -