Tailoring porous silica films through supercritical carbon dioxide processing of fluorinated surfactant templates

Kaustav Ghosh; Sandhya M Vyas; Hans-Joachim Lehmler; Stephen E Rankin; Barbara L Knutson

doi:10.1021/jp0656680

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Tailoring porous silica films through supercritical carbon dioxide processing of fluorinated surfactant templates

Journal article

Peer reviewed

Tailoring porous silica films through supercritical carbon dioxide processing of fluorinated surfactant templates

Kaustav Ghosh, Sandhya M Vyas, Hans-Joachim Lehmler, Stephen E Rankin and Barbara L Knutson

The journal of physical chemistry. B, Vol.111(2), pp.363-370

01/18/2007

DOI: 10.1021/jp0656680

PMID: 17214487

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Abstract

The tailoring of porous silica thin films synthesized using perfluoroalkylpyridinium chloride surfactants as templating agents is achieved as a function of carbon dioxide processing conditions and surfactant tail length and branching. Well-ordered films with 2D hexagonal close-packed pore structure are obtained from sol-gel synthesis using the following cationic fluorinated surfactants as templates: 1-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-octyl)pyridinium chloride (HFOPC), 1-(3,3,4,4,5,5,6,6,7,8,8,8-dodecafluoro-7-trifluoromethyl -octyl)pyridinium chloride (HFDoMePC), and 1-(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro-decyl)pyridinium chloride (HFDePC). Processing the sol-gel film with CO2 (69-172 bar, 25 and 45 degrees C) immediately after coating results in significant increases in pore diameter relative to the unprocessed thin films (increasing from 20% to 80% depending on surfactant template and processing conditions). Pore expansion increases with CO2 processing pressure, surfactant tail length, and surfactant branching. The varying degree of CO2 induced expansion is attributed to the solvation of the "CO2-philic" fluorinated tail and is interpreted from interfacial behavior of HFOPC, HFDoMePC, and HFDePC at the CO2-water interface.

Carbon Dioxide - chemistry

Cations - chemistry

Silicon Dioxide - chemical synthesis

Silicon Dioxide - chemistry

Membranes, Artificial

Hydrocarbons, Fluorinated - chemistry

Pressure

Particle Size

Micelles

Surface Properties

Molecular Structure

Surface-Active Agents - chemistry

Porosity

Details

Title: Subtitle: Tailoring porous silica films through supercritical carbon dioxide processing of fluorinated surfactant templates
Creators: Kaustav Ghosh - Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046, USA
Sandhya M Vyas
Hans-Joachim Lehmler
Stephen E Rankin
Barbara L Knutson
Resource Type: Journal article
Publication Details: The journal of physical chemistry. B, Vol.111(2), pp.363-370
DOI: 10.1021/jp0656680
PMID: 17214487
NLM abbreviation: J Phys Chem B
ISSN: 1520-6106
eISSN: 1520-5207
Publisher: American Chemical Society; United States
Language: English
Date published: 01/18/2007
Academic Unit: Occupational and Environmental Health; Iowa Neuroscience Institute
Record Identifier: 9984000932302771

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