Selective filling of n-hexane in a tight nanopore
Selective filling of n-hexane in a tight nanopore
Files
Publication or External Link
Date
2021-01-12
Authors
Qu, Haoran
Rayabharam, Archith
Wu, Xiaojian
Wang, Peng
Li, Yunfeng
Fagan, Jeffrey
Aluru, Narayana R.
Wang, YuHuang
Advisor
Citation
Qu, H., Rayabharam, A., Wu, X. et al. Selective filling of n-hexane in a tight nanopore. Nat Commun 12, 310 (2021).
DRUM DOI
Abstract
Molecular sieving may occur when two molecules compete for a nanopore. In nearly all known examples, the nanopore is larger than the molecule that selectively enters the pore. Here, we experimentally demonstrate the ability of single-wall carbon nanotubes with a van der Waals pore size of 0.42 nm to separate n-hexane from cyclohexane—despite the fact that both molecules have kinetic diameters larger than the rigid nanopore. This unexpected finding challenges our current understanding of nanopore selectivity and how molecules may enter a tight channel. Ab initio molecular dynamics simulations reveal that n-hexane molecules stretch by nearly 11.2% inside the nanotube pore. Although at a relatively low probability (28.5% overall), the stretched state of n-hexane does exist in the bulk solution, allowing the molecule to enter the tight pore even at room temperature. These insights open up opportunities to engineer nanopore selectivity based on the molecular degrees of freedom.
Notes
Partial funding for Open Access provided by the UMD Libraries' Open Access Publishing Fund.