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arXiv · 2609.36682

Polar-Domain Volume as a Unified Descriptor of Transport in Ionic Liquids

Ganesh K. Rajahmundry·Tarak K. Patra
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Abstract

Developing molecular scale structural descriptors that can quantitatively predict the macroscopic transport properties of ionic liquids remains a longstanding question, owing to the complex interplay between molecular interactions, nanoscale organization, and collective ion dynamics. Here, we use all atom molecular dynamics simulations to establish quantitative structure property relationships between the equilibrium microstructure and two key transport properties viscosity and ionic conductivity in a series of imidazolium based ILs with chemically distinct anions and varying alkyl chain lengths. While viscosity and ionic conductivity exhibit distinct dependencies on alkyl chain length and anion chemistry, these seemingly different trends largely collapse onto unified correlations when expressed in terms of the mean polar-domain volume. In particular, both transport properties exhibit systematic power-law scaling with the mean polar domain volume fraction, revealing a common structural origin underlying the variations in ion and momentum transport across chemically distinct ILs. These results establish polar-domain volume as a physically motivated molecular-scale descriptor and provide a general structure property framework for connecting nanoscale organization to macroscopic transport properties in ILs.

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Ganesh K. Rajahmundry, Tarak K. Patra. 2026-09-29. Polar-Domain Volume as a Unified Descriptor of Transport in Ionic Liquids. https://arxiv.org/abs/2609.36682

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