Nucleation, Coalescence, and Thin-Film Growth of Triflate-Based Ionic Liquids on ITO, Ag, and Au Surfaces

• Type: Article in International Scientific Journal
• Date: 2022

Authors

Teixeira, MSM (Author) Other; Luis M N B F Santos (Author) FCUP; Costa, JCS (Author) FCUP

Journal

Title: Colloids and Surfaces B: Biointerfaces

Vol. 6

Final page: 46

ISSN: 0927-7765

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 7 Citations

Scopus - 7 Citations

Other information

Authenticus ID: P-00X-7WT

DOI: 10.3390/colloids6030046

Abstract (EN): 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-[CnC1 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-2 to C-10). 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(n)C(1)im][OTF] series agrees with recent data for the [C(n)C(1)im][NTf2] congeners, highlighting the higher wettability of the solid substrates to long-chain alkylimidazolium cations. Compared to [NTf2], 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(6)C(1)im][OTF], emphasizing the effect of the nanostructuration intensification due to the formation of nonpolar continuous domains.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 16