Ordering and Nonideality of Air-Ionic Liquid Interfaces in Surface Second Harmonic Generation

• Type: Article in International Scientific Journal
• Date: 2020

Authors

Costa, R (Author) FCUP; Carlos M Pereira (Author) FCUP; Silva, F (Author) FCUP; Brevet, PF (Author) Other; Benichou, E (Author) Other

Journal

Title: Journal of Physical Chemistry B

Vol. 124

Pages: 3954-3961

ISSN: 1520-6106

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 11 Citations

Other information

Authenticus ID: P-00S-4T3

DOI: 10.1021/acs.jpcb.9b12025

Abstract (EN): The air-ionic liquid interface for a series of ionic liquids involving imidazolium cations [C(n)mim] with different alkyl chain lengths (n = 2, 4, 6, 8, 10, and 12) and the same [NTf2] imide anion has been studied by polarization-resolved second harmonic generation (SHG). An increase as a function of the alkyl chain length of the orientational parameter reveals the increasing ordering of the air-pure ionic liquid interfaces although it is not possible to disentangle the change in mean tilt angle from a change in the tilt angle probability distribution width. Besides, the study of the air-mixed ([C(12)mim])(x)([C(2)mim])(1-x)[NTf2] ionic liquid interface clearly demonstrates the interfacial nonideality of the mixed ionic liquids. The long alkyl chain cation perturbs the interface as seen from the orientational parameter and displaces the short alkyl chain one for bulk mixture contents as low as 10%. At higher long alkyl chain cation bulk mixture contents, the interface behaves close to a pure long alkyl chain ionic liquid.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8