1. Anion architecture controls structure and electroresponsivity of anhalogenous ionic liquids in a sustainable fluid
- Author
-
Li, Sichao, Hammond, Oliver S., Nelson, Andrew, de Campo, Liliana, Moir, Michael, Recsei, Carl, Shimpi, Manishkumar R., Glavatskih, Sergei, Pilkington, Georgia A., Mudring, Anja-Verena, Rutland, Mark W., Li, Sichao, Hammond, Oliver S., Nelson, Andrew, de Campo, Liliana, Moir, Michael, Recsei, Carl, Shimpi, Manishkumar R., Glavatskih, Sergei, Pilkington, Georgia A., Mudring, Anja-Verena, and Rutland, Mark W.
- Abstract
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.
- Published
- 2024
- Full Text
- View/download PDF