The Methyl Functionality of Monolithic Silica Xerogels Synthesized via the Co-Gelation Approach Combined with Surface Silylation
The present research aims to investigate the chemical and morphological properties of the methylated silica xerogels produced via the co-gelation approach combined with surface silylation. In the sol–gel synthesis, methyltrimethoxysilane (MTMS) and tetraethylorthosilicate (TEOS) were utilized as sil...
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MDPI AG
2022-12-01
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| Online Access: | https://www.mdpi.com/2310-2861/9/1/33 |
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| author | Selay Sert Çok Fatoş Koç Zoltán Dudás Nilay Gizli |
| author_facet | Selay Sert Çok Fatoş Koç Zoltán Dudás Nilay Gizli |
| author_sort | Selay Sert Çok |
| collection | DOAJ |
| description | The present research aims to investigate the chemical and morphological properties of the methylated silica xerogels produced via the co-gelation approach combined with surface silylation. In the sol–gel synthesis, methyltrimethoxysilane (MTMS) and tetraethylorthosilicate (TEOS) were utilized as silica precursors and trimethylchlorosilane (TMCS) served as a silylating agent. Structural changes were observed depending on the MTMS/TEOS molar ratio and on the post-synthesis-performed surface silylation of the xerogels. Post-synthesis silylation plays a critical role in the exchanging of the surface silanols with methyl groups, preserving the monolithic form. The morphological and structural changes were followed by SEM, <sup>29</sup>Si-MAS-NMR, FTIR spectroscopy, nitrogen porosimetry, and contact angle measurements. The results have shown significant structural variations depending especially on the MTMS content. With an increasing MTMS content, the morphology of the samples has changed from a micro/mesoporous texture to a meso/macroporous texture. A higher degree of methyl substitution has been achieved for the silylated samples both confirmed by the FTIR and <sup>29</sup>Si-NMR results. On the other hand, only the samples with a high MTMS content could preserve their structural integrity after evaporative drying, and all have exhibited a high degree of hydrophobicity with θ > 140°. |
| first_indexed | 2024-03-09T12:38:12Z |
| format | Article |
| id | doaj.art-b808e3b4937643a687bbd31d4d4c2839 |
| institution | Directory Open Access Journal |
| issn | 2310-2861 |
| language | English |
| last_indexed | 2024-03-09T12:38:12Z |
| publishDate | 2022-12-01 |
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| spelling | doaj.art-b808e3b4937643a687bbd31d4d4c28392023-11-30T22:21:31ZengMDPI AGGels2310-28612022-12-01913310.3390/gels9010033The Methyl Functionality of Monolithic Silica Xerogels Synthesized via the Co-Gelation Approach Combined with Surface SilylationSelay Sert Çok0Fatoş Koç1Zoltán Dudás2Nilay Gizli3Chemical Engineering Department, Ege University, İzmir 35100, TurkeyChemical Engineering Department, Ege University, İzmir 35100, TurkeyCentre for Energy Research, Neutron Spectroscopy Department, 1121 Budapest, HungaryChemical Engineering Department, Ege University, İzmir 35100, TurkeyThe present research aims to investigate the chemical and morphological properties of the methylated silica xerogels produced via the co-gelation approach combined with surface silylation. In the sol–gel synthesis, methyltrimethoxysilane (MTMS) and tetraethylorthosilicate (TEOS) were utilized as silica precursors and trimethylchlorosilane (TMCS) served as a silylating agent. Structural changes were observed depending on the MTMS/TEOS molar ratio and on the post-synthesis-performed surface silylation of the xerogels. Post-synthesis silylation plays a critical role in the exchanging of the surface silanols with methyl groups, preserving the monolithic form. The morphological and structural changes were followed by SEM, <sup>29</sup>Si-MAS-NMR, FTIR spectroscopy, nitrogen porosimetry, and contact angle measurements. The results have shown significant structural variations depending especially on the MTMS content. With an increasing MTMS content, the morphology of the samples has changed from a micro/mesoporous texture to a meso/macroporous texture. A higher degree of methyl substitution has been achieved for the silylated samples both confirmed by the FTIR and <sup>29</sup>Si-NMR results. On the other hand, only the samples with a high MTMS content could preserve their structural integrity after evaporative drying, and all have exhibited a high degree of hydrophobicity with θ > 140°.https://www.mdpi.com/2310-2861/9/1/33xerogelssilylationco-gelation |
| spellingShingle | Selay Sert Çok Fatoş Koç Zoltán Dudás Nilay Gizli The Methyl Functionality of Monolithic Silica Xerogels Synthesized via the Co-Gelation Approach Combined with Surface Silylation Gels xerogels silylation co-gelation |
| title | The Methyl Functionality of Monolithic Silica Xerogels Synthesized via the Co-Gelation Approach Combined with Surface Silylation |
| title_full | The Methyl Functionality of Monolithic Silica Xerogels Synthesized via the Co-Gelation Approach Combined with Surface Silylation |
| title_fullStr | The Methyl Functionality of Monolithic Silica Xerogels Synthesized via the Co-Gelation Approach Combined with Surface Silylation |
| title_full_unstemmed | The Methyl Functionality of Monolithic Silica Xerogels Synthesized via the Co-Gelation Approach Combined with Surface Silylation |
| title_short | The Methyl Functionality of Monolithic Silica Xerogels Synthesized via the Co-Gelation Approach Combined with Surface Silylation |
| title_sort | methyl functionality of monolithic silica xerogels synthesized via the co gelation approach combined with surface silylation |
| topic | xerogels silylation co-gelation |
| url | https://www.mdpi.com/2310-2861/9/1/33 |
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