Repair of Porous Methylsilsesquioxane Films using Supercritical Carbon Dioxide

2004 ◽  
Vol 812 ◽  
Author(s):  
Bo Xie ◽  
Anthony J. Muscat
Keyword(s):  
Carbon Dioxide ◽  
Dielectric Constant ◽  
Fourier Transform ◽  
Supercritical Carbon Dioxide ◽  
Ftir Spectroscopy ◽  
Oxygen Plasma ◽  
Contact Angles ◽  
Silanol Groups ◽  
Chain Lengths ◽  
Supercritical Carbon

AbstractPorous methylsilsesquioxane (p-MSQ) films (JSR LKD 5109) were treated with alkyldimethylmonochlorosilanes having chain lengths of one, four, and eight carbon atoms dissolved in supercritical carbon dioxide at 150-300 atm and 50-60°C to repair oxygen ashing damage. Fourier transform infrared (FTIR) spectroscopy showed that trimethylchlorosilane (TMCS), butyldimethylchlorosilane (BDMCS), and octyldimethylchlorosilane (ODMCS) reacted with silanol groups on the surfaces of the pores producing covalent Si-O-Si bonds. Selfcondensation between alkylsilanols produced a residue on the surface, which was partially removed using a pure scCO2 rinse. The hydrophobicity of the blanket p-MSQ surface was recovered after silylation treatment as shown by contact angles >85°. The initial dielectric constant of 2.4 ± 0.1 increased to 3.5 ± 0.1 after oxygen plasma ashing and was reduced to 2.6 ± 0.1 by TMCS, 2.8 ± 0.1 by BDMCS, and 3.2 by ODMCS.

Repair of Porous MSQ (p-MSQ) Films Using Monochlorosilanes Dissolved in Supercritical CO2

2005 ◽  
Vol 103-104 ◽  
pp. 323-326 ◽  
Author(s):  
Bo Xie ◽  
Anthony Muscat
Keyword(s):  
Carbon Dioxide ◽  
Contact Angle ◽  
Dielectric Constant ◽  
Fourier Transform ◽  
Supercritical Carbon Dioxide ◽  
Alkyl Chain ◽  
Electrical Measurements ◽  
Metal Insulator ◽  
Pore Sealing ◽  
Chain Lengths

Fourier transform infrared (FTIR) spectroscopy, contact angle, and electrical measurements were used to study porous methylsilsesquioxane (p-MSQ) films (JSR LKD 5109) processed with alkylmonochlorosilanes having chain lengths of one to eighteen carbon atoms dissolved in supercritical carbon dioxide at 155-185 atm and 55-60°C to repair oxygen ashing damage. The FTIR results showed that all chemistries reacted with silanol groups on the surface of the pores producing covalent Si-O-Si bonds. Self-condensation between the alkylsilanols with chain lengths above four carbon atoms produced a physisorbed residue, which was partially removed after rinsing with pure scCO2. The hydrophobicity of the blanket p-MSQ surface was recovered, while the initial dielectric constant of 2.4 for the blanket p-MSQ surface was restored after treatment. With an increase in the length of the alkyl chain, the contact angle increased from 84° to 108° and the dielectric constant measured on metal-insulator-semiconductor capacitors was approximately constant in the range 2.4 ± 0.05. The monochlorosilanes restore the dielectric constant and surface properties of mesoporous p-MSQ and are candidate pore sealing additives.

Application of online infrared spectroscopy to study the kinetics of precipitation polymerization of acrylic acid in supercritical carbon dioxide

2016 ◽  
Vol 1 (4) ◽  
pp. 372-378 ◽  
Author(s):  
Jean-Noël Ollagnier ◽  
Thierry Tassaing ◽  
Simon Harrisson ◽  
Mathias Destarac
Keyword(s):  
Carbon Dioxide ◽  
Infrared Spectroscopy ◽  
Supercritical Carbon Dioxide ◽  
Acrylic Acid ◽  
Ftir Spectroscopy ◽  
Precipitation Polymerization ◽  
Kinetics Of Precipitation ◽  
Kinetics Of ◽  
Supercritical Carbon

The kinetics of precipitation polymerization of acrylic acid in supercritical CO2 is monitored by in situ FTIR spectroscopy.

Characterization of a Two-Phase Pore-Scale Network Model of Supercritical Carbon Dioxide Transport Within Brine-Filled Porous Media

2011 ◽  
Author(s):  
J. S. Ellis ◽  
A. Ebrahimi ◽  
A. Bazylak
Keyword(s):  
Carbon Dioxide ◽  
Porous Media ◽  
Supercritical Carbon Dioxide ◽  
Network Model ◽  
Pore Network ◽  
Contact Angles ◽  
Pore Network Model ◽  
Pore Scale ◽  
Two Phase ◽  
Supercritical Carbon

Sequestration of carbon dioxide in deep underground reservoirs has been discussed for the reduction of atmospheric greenhouse gas emissions in the short- to medium-term until more sustainable technologies are available. Cost and long-term stability are major factors in adoption, so techniques to improve the storage efficiency and trapping security are essential. Such improvements require modeling of the porous geological formations involved in the sequestration process, and comparison to both lab- and field-based experimental studies. To this end, we are developing a comprehensive, large-scale pore-network model to describe multi-phase flow in porous media, including the structural, dissolution, and mineral trapping regimes. To explore the optimal operating parameters for mineralization trapping, we describe a two-phase pore-network model of brine-saturated aquifers and model the invasion of supercritical carbon dioxide (CO2) into the pore structure. Regularly-aligned 2D and 3D pore networks are constructed, and rules-based transport models are used to characterize the saturation behavior over a range of viscosity and capillary parameters, and coordination numbers. Finally, saturation patterns are presented for model caprock and sandstone reservoir conditions, taking into account different contact angles for CO2 on mica and quartz at supercritical conditions. These saturation patterns demonstrate the importance of surface heterogeneities in pore-scale modeling of deep saline aquifers.

scholarly journals Supercritical Carbon Dioxide Treatment of Porous Silicon Increases Biocompatibility with Cardiomyocytes

2021 ◽  
Vol 22 (19) ◽  
pp. 10709
Author(s):  
David Jui-Yang Feng ◽  
Hung-Yin Lin ◽  
James L. Thomas ◽  
Hsing-Yu Wang ◽  
Chien-Yu Lin ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Porous Silicon ◽  
Supercritical Carbon Dioxide ◽  
Oxygen Plasma ◽  
Cardiac Tissue ◽  
Hydrophobic Surface ◽  
Cellular Behavior ◽  
H9c2 Cardiomyocytes ◽  
Angiogenesis Pathway ◽  
Supercritical Carbon

Porous silicon is of current interest for cardiac tissue engineering applications. While porous silicon is considered to be a biocompatible material, it is important to assess whether post-etching surface treatments can further improve biocompatibility and perhaps modify cellular behavior in desirable ways. In this work, porous silicon was formed by electrochemically etching with hydrofluoric acid, and was then treated with oxygen plasma or supercritical carbon dioxide (scCO2). These processes yielded porous silicon with a thickness of around 4 μm. The different post-etch treatments gave surfaces that differed greatly in hydrophilicity: oxygen plasma-treated porous silicon had a highly hydrophilic surface, while scCO2 gave a more hydrophobic surface. The viabilities of H9c2 cardiomyocytes grown on etched surfaces with and without these two post-etch treatments was examined; viability was found to be highest on porous silicon treated with scCO2. Most significantly, the expression of some key genes in the angiogenesis pathway was strongly elevated in cells grown on the scCO2-treated porous silicon, compared to cells grown on the untreated or plasma-treated porous silicon. In addition, the expression of several apoptosis genes were suppressed, relative to the untreated or plasma-treated surfaces.

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