RT info:eu-repo/semantics/article
T1 Effect of ion structure on the physicochemical properties and gas absorption of surface active ionic liquids
A1 Ávila, Jocasta
A1 Lozano-Martín, Daniel
A1 Simões Santos, Mirella
A1 Zhang, Yunxiao
A1 Li, Hua
A1 Pádua, Agilio
A1 Atkin, Rob
A1 Costa Gomes, Margarida
AB Surface active ionic liquids (SAILs) combine useful characteristics of both ionic liquids (ILs) and surfactants, hence are promising candidates for a wide range of applications. However, the effect of SAIL ionic structures on their physicochemical properties remains unclear, which limits their uptake. To address this knowledge gap, in this work we investigated the density, viscosity, surface tension, and corresponding critical micelle concentration in water, as well as gas absorption of SAILs with a variety of cation and anion structures. SAILs containing anions with linear alkyl chains have smaller molar volumes than those with branched alkyl chains, because linear alkyl chains are interdigitated to a greater extent, leading to more compact packing. This interdigitation also results in SAILs being about two orders of magnitude more viscous than comparable conventional ILs. SAILs at the liquid–air interface orient alkyl chains towards the air, leading to low surface tensions closer to n-alkanes than conventional ILs. Critical temperatures of about 900 K could be estimated for all SAILs from their surface tensions. When dissolved in water, SAILs adsorb at the liquid–air interface and lower the surface tension, like conventional surfactants in water, after which micelles form. Molecular simulations show that the micelles are spherical and that lower critical micelle concentrations correspond to the formation of aggregates with a larger number of ion pairs. CO2 and N2 absorption capacities are examined and we conclude that ionic liquids with larger non-polar domains absorb larger quantities of both gases.
SN 1463-9076
YR 2023
FD 2023
LK https://uvadoc.uva.es/handle/10324/69134
UL https://uvadoc.uva.es/handle/10324/69134
LA spa
NO Physical Chemistry Chemical Physics, 2023, vol. 25, p. 6808-6816.
DS UVaDOC
RD 27-jul-2024