Anion Architecture Controls Structure and Electroresponsivity of Anhalogenous Ionic Liquids in a Sustainable FluidShow others and affiliations
2024 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 128, no 17, p. 4231-4242Article in journal (Refereed) Published
Abstract [en]
Three nonhalogenated ionic liquids (ILs) dissolved in 2-ethylhexyl laurate (2-EHL), a biodegradable oil, are investigated in terms of their bulk and electro-interfacial nanoscale structures using small-angle neutron scattering (SANS) and neutron reflectivity (NR). The ILs share the same trihexyl(tetradecyl)phosphonium ([P6,6,6,14]+) cation paired with different anions, bis(mandelato)borate ([BMB]−), bis(oxalato)borate ([BOB]−), and bis(salicylato)borate ([BScB]−). SANS shows a high aspect ratio tubular self-assembly structure characterized by an IL core of alternating cations and anions with a 2-EHL-rich shell or corona in the bulk, the geometry of which depends upon the anion structure and concentration. NR also reveals a solvent-rich interfacial corona layer. Their electro-responsive behavior, pertaining to the structuring and composition of the interfacial layers, is also influenced by the anion identity. [P6,6,6,14][BOB] exhibits distinct electroresponsiveness to applied potentials, suggesting an ion exchange behavior from cation-dominated to anion-rich. Conversely, [P6,6,6,14][BMB] and [P6,6,6,14][BScB] demonstrate minimal electroresponses across all studied potentials, related to their different dissociative and diffusive behavior. A mixed system is dominated by the least soluble IL but exhibits an increase in disorder. This work reveals the subtlety of anion architecture in tuning bulk and electro-interfacial properties, offering valuable molecular insights for deploying nonhalogenated ILs as additives in biodegradable lubricants and supercapacitors.
Place, publisher, year, edition, pages
American Chemical Society , 2024. Vol. 128, no 17, p. 4231-4242
Keywords [en]
Additives, Aspect ratio, Ion exchange, Negative ions, Neutron scattering, Positive ions, anion, boric acid, cation, ionic liquid, lauric acid, lubricating agent, nanomaterial, solvent, Bio-degradable oil, Control structure, High aspect ratio, Laurate, Nanoscale structure, Neutron reflectivity, Oxalato, Self-assembly structure, Small-angle neutron scattering, Tubulars, article, controlled study, geometry, ion exchange, liquid, neutron scattering, nonhuman, Ionic liquids
National Category
Physical Chemistry
Identifiers
URN: urn:nbn:se:ri:diva-73270DOI: 10.1021/acs.jpcb.3c08189Scopus ID: 2-s2.0-85191147484OAI: oai:DiVA.org:ri-73270DiVA, id: diva2:1864637
Funder
Knut and Alice Wallenberg Foundation, KAW2012.0078Swedish Research Council, 2017-04080Swedish Foundation for Strategic Research, EM16-0013, "REFIT"Vinnova, 2020-03801
Note
We acknowledge the support of the Australian Centre for Neutron Scattering, ANSTO, and the Australian Government through the National Collaborative Research Infrastructure Strategy (NCRIS), in using the neutron research infrastructure used in this work via ACNS proposal P13958 on the BILBY SANS and proposal P8264 on the PLATYPUS NR instrument. We gratefully acknowledge Institut Laue-Langevin (ILL), France, for access to SuperADAM (doi:10.5291/ILL-DATA.9-13-1006). We acknowledge the support of the Australian Government in provision of access to ANSTO's National Deuteration Facility which is partly funded through NCRIS. Prof. Oleg N. Antzutkin (Luleå University of Technology) is gratefully acknowledged for providing the ILs. The authors thank Prof. Thomas Norrby (KTH Royal Institute of Technology and Nynas AB) for insightful discussions on 2-EHL properties and applications. The authors would also like to thank Dr. Alexei Vorobiev for his support during the SuperADAM beamtime and Dr. Brando Adranno, Dr. Olivier Renier, Anthony Boudier, and Filip Mehler for their experimental support. Daniel Morris is thanked for valuable assistance performing SANS experiments. SL and GP also thank Dr. Adrian Iovan (KTH Nanolab) for his help with the preparation of the gold electrode via the electron beam evaporator. The Knut and Alice Wallenberg Foundation (Project no. KAW2012.0078), the Swedish Research Council, VR (Project no. 2017-04080), the Swedish Foundation for Strategic Research (Project no. EM16-0013, "REFIT"), Vinnova (Project no. 2020-03801), and Villum Foundation (Villum Investigator awards to AVM) are acknowledged for their financial support. We also thank the Danish Agency for Science, Technology, and Innovation for funding the instrument center DanScatt (Grant no. 2021 7129-00006B).
2024-06-032024-06-032024-06-03Bibliographically approved