Influence of the Deposition Rate and Substrate Temperature on the Morphology of Thermally Evaporated Ionic Liquids

• Tipo: Artigo em Revista Científica Internacional
• Data: 2023

Autores

Carvalho, RM (Autor) Outra; Neto, C (Autor) Outra; Luis M N B F Santos (Autor) FCUP; Bastos, M (Autor) FCUP; Costa, JCS (Autor) FCUP

Revista

A Revista está pendente de validação pelos Serviços Administrativos.

Título: FLUIDS

Vol. 8

Página Final: 105

ISSN: 2311-5521

Indexação

ISI Web of Knowledge - 1 Citação

Scopus - 1 Citação

Outras Informações

ID Authenticus: P-00Y-5DQ

DOI: 10.3390/fluids8030105

Abstract (EN): The wetting behavior of ionic liquids (ILs) on the mesoscopic scale considerably impacts a wide range of scientific fields and technologies. Particularly under vacuum conditions, these materials exhibit unique characteristics. This work explores the effect of the deposition rate and substrate temperature on the nucleation, droplet formation, and droplet spreading of ILs films obtained by thermal evaporation. Four ILs were studied, encompassing an alkylimidazolium cation (C(n)C(1)im) and either bis(trifluoromethylsulfonyl)imide (NTf2) or the triflate (OTf) as the anion. Each IL sample was simultaneously deposited on surfaces of indium tin oxide (ITO) and silver (Ag). The mass flow rate was reproducibly controlled using a Knudsen cell as an evaporation source, and the film morphology (micro- and nanodroplets) was evaluated by scanning electron microscopy (SEM). The wettability of the substrates by the ILs was notably affected by changes in mass flow rate and substrate temperature. Specifically, the results indicated that an increase in the deposition rate and/or substrate temperature intensified the droplet coalescence of [C(2)C(1)im][NTf2] and [C(2)C(1)im][OTf] on ITO surfaces. Conversely, a smaller impact was observed on the Ag surface due to the strong adhesion between the ILs and the metallic film. Furthermore, modifying the deposition parameters resulted in a noticeable differentiation in the droplet morphology obtained for [C(8)C(1)im][NTf2] and [C(8)C(1)im][OTf]. Nevertheless, droplets from long-chain ILs deposited on ITO surfaces showed intensified coalescence, regardless of the deposition rate or substrate temperature.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 17