Nucleation, Coalescence, and Thin-Film Growth of Triflate-Based Ionic Liquids on ITO, Ag, and Au Surfaces
This study investigates the nucleation and growth of micro-/nanodroplets of triflate-based ionic liquids (ILs) fabricated by vapor deposition on different surfaces: indium tin oxide (ITO); silver (Ag); gold (Au). The ILs studied are constituted by the alkylimidazolium cation and the triflate anion—[...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-09-01
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| Series: | Colloids and Interfaces |
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| Online Access: | https://www.mdpi.com/2504-5377/6/3/46 |
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| author | Mariana S. M. Teixeira Luís M. N. B. F. Santos José C. S. Costa |
| author_facet | Mariana S. M. Teixeira Luís M. N. B. F. Santos José C. S. Costa |
| author_sort | Mariana S. M. Teixeira |
| collection | DOAJ |
| description | This study investigates the nucleation and growth of micro-/nanodroplets of triflate-based ionic liquids (ILs) fabricated by vapor deposition on different surfaces: indium tin oxide (ITO); silver (Ag); gold (Au). The ILs studied are constituted by the alkylimidazolium cation and the triflate anion—[C<i><sub>n</sub></i>C<sub>1</sub>im][OTF] series. One of the key issues that determine the potential applications of ILs is the wettability of surfaces. Herein, the wetting behavior was evaluated by changing the cation alkyl chain length (C<sub>2</sub> to C<sub>10</sub>). A reproducible control of the deposition rate was conducted employing Knudsen cells, and the thin-film morphology was evaluated by high-resolution scanning electron microscopy (SEM). The study reported here for the [C<i><sub>n</sub></i>C<sub>1</sub>im][OTF] series agrees with recent data for the [C<i><sub>n</sub></i>C<sub>1</sub>im][NTf<sub>2</sub>] congeners, highlighting the higher wettability of the solid substrates to long-chain alkylimidazolium cations. Compared to [NTf<sub>2</sub>], the [OTF] series evidenced an even more pronounced wetting ability on Au and coalescence processes of droplets highly intense on ITO. Higher homogeneity and film cohesion were found for cationic groups associated with larger alkyl side chains. An island growth was observed on both Ag and ITO substrates independently of the cation alkyl chain length. The Ag surface promoted the formation of smaller-size droplets. A quantitative analysis of the number of microdroplets formed on Ag and ITO revealed a trend shift around [C<sub>6</sub>C<sub>1</sub>im][OTF], emphasizing the effect of the nanostructuration intensification due to the formation of nonpolar continuous domains. |
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| institution | Directory Open Access Journal |
| issn | 2504-5377 |
| language | English |
| last_indexed | 2024-03-10T00:21:34Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Colloids and Interfaces |
| spelling | doaj.art-2b051eb855a14a55bfdd62259426df6b2023-11-23T15:41:17ZengMDPI AGColloids and Interfaces2504-53772022-09-01634610.3390/colloids6030046Nucleation, Coalescence, and Thin-Film Growth of Triflate-Based Ionic Liquids on ITO, Ag, and Au SurfacesMariana S. M. Teixeira0Luís M. N. B. F. Santos1José C. S. Costa2CIQUP, Institute of Molecular Sciences (IMS), Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, P4169-007 Porto, PortugalCIQUP, Institute of Molecular Sciences (IMS), Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, P4169-007 Porto, PortugalCIQUP, Institute of Molecular Sciences (IMS), Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, P4169-007 Porto, PortugalThis study investigates the nucleation and growth of micro-/nanodroplets of triflate-based ionic liquids (ILs) fabricated by vapor deposition on different surfaces: indium tin oxide (ITO); silver (Ag); gold (Au). The ILs studied are constituted by the alkylimidazolium cation and the triflate anion—[C<i><sub>n</sub></i>C<sub>1</sub>im][OTF] series. One of the key issues that determine the potential applications of ILs is the wettability of surfaces. Herein, the wetting behavior was evaluated by changing the cation alkyl chain length (C<sub>2</sub> to C<sub>10</sub>). A reproducible control of the deposition rate was conducted employing Knudsen cells, and the thin-film morphology was evaluated by high-resolution scanning electron microscopy (SEM). The study reported here for the [C<i><sub>n</sub></i>C<sub>1</sub>im][OTF] series agrees with recent data for the [C<i><sub>n</sub></i>C<sub>1</sub>im][NTf<sub>2</sub>] congeners, highlighting the higher wettability of the solid substrates to long-chain alkylimidazolium cations. Compared to [NTf<sub>2</sub>], the [OTF] series evidenced an even more pronounced wetting ability on Au and coalescence processes of droplets highly intense on ITO. Higher homogeneity and film cohesion were found for cationic groups associated with larger alkyl side chains. An island growth was observed on both Ag and ITO substrates independently of the cation alkyl chain length. The Ag surface promoted the formation of smaller-size droplets. A quantitative analysis of the number of microdroplets formed on Ag and ITO revealed a trend shift around [C<sub>6</sub>C<sub>1</sub>im][OTF], emphasizing the effect of the nanostructuration intensification due to the formation of nonpolar continuous domains.https://www.mdpi.com/2504-5377/6/3/46ionic liquidstriflateimidazoliumphysical vapor depositionthin filmsnanodroplets |
| spellingShingle | Mariana S. M. Teixeira Luís M. N. B. F. Santos José C. S. Costa Nucleation, Coalescence, and Thin-Film Growth of Triflate-Based Ionic Liquids on ITO, Ag, and Au Surfaces Colloids and Interfaces ionic liquids triflate imidazolium physical vapor deposition thin films nanodroplets |
| title | Nucleation, Coalescence, and Thin-Film Growth of Triflate-Based Ionic Liquids on ITO, Ag, and Au Surfaces |
| title_full | Nucleation, Coalescence, and Thin-Film Growth of Triflate-Based Ionic Liquids on ITO, Ag, and Au Surfaces |
| title_fullStr | Nucleation, Coalescence, and Thin-Film Growth of Triflate-Based Ionic Liquids on ITO, Ag, and Au Surfaces |
| title_full_unstemmed | Nucleation, Coalescence, and Thin-Film Growth of Triflate-Based Ionic Liquids on ITO, Ag, and Au Surfaces |
| title_short | Nucleation, Coalescence, and Thin-Film Growth of Triflate-Based Ionic Liquids on ITO, Ag, and Au Surfaces |
| title_sort | nucleation coalescence and thin film growth of triflate based ionic liquids on ito ag and au surfaces |
| topic | ionic liquids triflate imidazolium physical vapor deposition thin films nanodroplets |
| url | https://www.mdpi.com/2504-5377/6/3/46 |
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