Suppression of Hydrophobic Recovery in Photo-Initiated Chemical Vapor Deposition
Photo-initiated chemical vapor deposition (PICVD) functionalizes carbon nanotube (CNT)-enhanced porous substrates with a highly polar polymeric nanometric film, rendering them super-hydrophilic. Despite its ability to generate fully wettable surfaces at low temperatures and atmospheric pressure, PIC...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-05-01
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| Series: | Catalysts |
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| Online Access: | https://www.mdpi.com/2073-4344/10/5/534 |
| _version_ | 1797568210987384832 |
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| author | Alessio Aufoujal Ulrich Legrand Jean-Luc Meunier Jason Robert Tavares |
| author_facet | Alessio Aufoujal Ulrich Legrand Jean-Luc Meunier Jason Robert Tavares |
| author_sort | Alessio Aufoujal |
| collection | DOAJ |
| description | Photo-initiated chemical vapor deposition (PICVD) functionalizes carbon nanotube (CNT)-enhanced porous substrates with a highly polar polymeric nanometric film, rendering them super-hydrophilic. Despite its ability to generate fully wettable surfaces at low temperatures and atmospheric pressure, PICVD coatings normally undergo hydrophobic recovery. This is a process by which a percentage of oxygenated functional group diffuse/re-arrange from the top layer of the deposited film towards the bulk of the substrate, taking the induced hydrophilic property of the material with them. Thus, hydrophilicity decreases over time. To address this, a vertical chemical gradient (VCG) can be deposited onto the CNT-substrate. The VCG consists of a first, thicker highly cross-linked layer followed by a second, thinner highly functionalized layer. In this article, we show, through water contact angle and XPS measurements, that the increased cross-linking density of the first layer can reduce the mobility of polar functional groups, forcing them to remain at the topmost layer of the PICVD coating and to suppress hydrophobic recovery. We show that employing a bi-layer VCG suppresses hydrophobic recovery for five days and reduces its effect afterwards (contact angle stabilizes to 42 ± 1° instead of 125 ± 3°). |
| first_indexed | 2024-03-10T19:53:13Z |
| format | Article |
| id | doaj.art-0fbf7f09a11a4bffb00152f767a15930 |
| institution | Directory Open Access Journal |
| issn | 2073-4344 |
| language | English |
| last_indexed | 2024-03-10T19:53:13Z |
| publishDate | 2020-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Catalysts |
| spelling | doaj.art-0fbf7f09a11a4bffb00152f767a159302023-11-20T00:10:13ZengMDPI AGCatalysts2073-43442020-05-0110553410.3390/catal10050534Suppression of Hydrophobic Recovery in Photo-Initiated Chemical Vapor DepositionAlessio Aufoujal0Ulrich Legrand1Jean-Luc Meunier2Jason Robert Tavares3Research Center for High Performance Polymer and Composite Systems (CREPEC), Department of Chemical Engineering Department, Polytechnique Montreal, Montreal, QC H3C 3A7, CanadaResearch Center for High Performance Polymer and Composite Systems (CREPEC), Department of Chemical Engineering Department, Polytechnique Montreal, Montreal, QC H3C 3A7, CanadaPlasma Processing Laboratory, Department of Chemical Engineering, McGill University, Montreal, QC H3A 2B2, CanadaResearch Center for High Performance Polymer and Composite Systems (CREPEC), Department of Chemical Engineering Department, Polytechnique Montreal, Montreal, QC H3C 3A7, CanadaPhoto-initiated chemical vapor deposition (PICVD) functionalizes carbon nanotube (CNT)-enhanced porous substrates with a highly polar polymeric nanometric film, rendering them super-hydrophilic. Despite its ability to generate fully wettable surfaces at low temperatures and atmospheric pressure, PICVD coatings normally undergo hydrophobic recovery. This is a process by which a percentage of oxygenated functional group diffuse/re-arrange from the top layer of the deposited film towards the bulk of the substrate, taking the induced hydrophilic property of the material with them. Thus, hydrophilicity decreases over time. To address this, a vertical chemical gradient (VCG) can be deposited onto the CNT-substrate. The VCG consists of a first, thicker highly cross-linked layer followed by a second, thinner highly functionalized layer. In this article, we show, through water contact angle and XPS measurements, that the increased cross-linking density of the first layer can reduce the mobility of polar functional groups, forcing them to remain at the topmost layer of the PICVD coating and to suppress hydrophobic recovery. We show that employing a bi-layer VCG suppresses hydrophobic recovery for five days and reduces its effect afterwards (contact angle stabilizes to 42 ± 1° instead of 125 ± 3°).https://www.mdpi.com/2073-4344/10/5/534hydrophobic recoveryphotochemistrysuperhydrophilicityhomogenous catalysis |
| spellingShingle | Alessio Aufoujal Ulrich Legrand Jean-Luc Meunier Jason Robert Tavares Suppression of Hydrophobic Recovery in Photo-Initiated Chemical Vapor Deposition Catalysts hydrophobic recovery photochemistry superhydrophilicity homogenous catalysis |
| title | Suppression of Hydrophobic Recovery in Photo-Initiated Chemical Vapor Deposition |
| title_full | Suppression of Hydrophobic Recovery in Photo-Initiated Chemical Vapor Deposition |
| title_fullStr | Suppression of Hydrophobic Recovery in Photo-Initiated Chemical Vapor Deposition |
| title_full_unstemmed | Suppression of Hydrophobic Recovery in Photo-Initiated Chemical Vapor Deposition |
| title_short | Suppression of Hydrophobic Recovery in Photo-Initiated Chemical Vapor Deposition |
| title_sort | suppression of hydrophobic recovery in photo initiated chemical vapor deposition |
| topic | hydrophobic recovery photochemistry superhydrophilicity homogenous catalysis |
| url | https://www.mdpi.com/2073-4344/10/5/534 |
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