Ion Selectivity in Uncharged Tapered Nanoslits through Heterogeneous Water Polarization
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| Main Authors: | , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866914057647292416 |
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| author | Veenstra, Tim Campos-Villalobos, Gerardo Giunta, Giuliana van Roij, René Dijkstra, Marjolein |
| author_facet | Veenstra, Tim Campos-Villalobos, Gerardo Giunta, Giuliana van Roij, René Dijkstra, Marjolein |
| contents | We employ molecular dynamics simulations to investigate ion and water transport driven by an electric field through quasi-two-dimensional nanoslits with a tapered geometry. Despite the absence of surface charge on the channel walls and the associated electric double layer, we do observe a robust ion selectivity. This selectivity favors the transport of cations from base to tip when the electric field is directed from base to tip, and anions from base to tip when the field direction is reversed. Additionally, we observe a corresponding electro-osmotic water flow from base to tip, regardless of the electric field direction. Intriguingly, ion selectivity and electro-osmotic flow are conventionally associated with surface charge and electric double layers. However, in uncharged tapered nanoslits, we uncover a novel mechanism for these phenomena, where ion selectivity arises from the divergence of the heterogeneous water polarization. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2407_10658 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Ion Selectivity in Uncharged Tapered Nanoslits through Heterogeneous Water Polarization Veenstra, Tim Campos-Villalobos, Gerardo Giunta, Giuliana van Roij, René Dijkstra, Marjolein Soft Condensed Matter We employ molecular dynamics simulations to investigate ion and water transport driven by an electric field through quasi-two-dimensional nanoslits with a tapered geometry. Despite the absence of surface charge on the channel walls and the associated electric double layer, we do observe a robust ion selectivity. This selectivity favors the transport of cations from base to tip when the electric field is directed from base to tip, and anions from base to tip when the field direction is reversed. Additionally, we observe a corresponding electro-osmotic water flow from base to tip, regardless of the electric field direction. Intriguingly, ion selectivity and electro-osmotic flow are conventionally associated with surface charge and electric double layers. However, in uncharged tapered nanoslits, we uncover a novel mechanism for these phenomena, where ion selectivity arises from the divergence of the heterogeneous water polarization. |
| title | Ion Selectivity in Uncharged Tapered Nanoslits through Heterogeneous Water Polarization |
| topic | Soft Condensed Matter |
| url | https://arxiv.org/abs/2407.10658 |