Work

Aromatic Peptide‐Enabled Cation‐π Engineering in Lamellar Nanochannels for Enhanced Cation Selectivity

Year: 2026

Type: article

Abstract: ABSTRACT Ion selectivity is central to nanochannel membranes for ion separation, molecular recognition, and energy conversion. However, conventional membranes primarily rely on electrostatic repulsion to regulate ion selectivity; the short‐range and weak nature limits high selectivity. Herein, a cation‐π engineering strategy is proposed by intercalating aromatic peptides (APs) into sub‐nanometer graphene oxide (GO) channels. Systematic tuning of the π‐system with phenylalanine (F)‐, tyrosine (Y)‐, and tryptophan (W)‐based peptides reveals a dual role of cation‐π interactions, involving electrostatic attraction and cation confinement. Specifically, the Y‐based AP‐intercalated GO membrane achieves a cation transference number of 0.614, representing a 16.95% improvement over GO membrane, which is attributed to electrostatic attraction of π‐system toward cations. Significantly, experiments and simulations reveal a nonmonotonic relation between selectivity and π‐system density, excessive π‐system density strengthens confinement and compromises selectivity. Moreover, the W‐based AP‐intercalated GO membrane exhibits a maximum power density of 20.11 W/m 2 under a 50‐fold NaCl gradient through an optimized selectivity‐permeability balance. Notably, the power density is increased to 29.99 W/m 2 after introducing Mg 2+ , which competitively occupies indole π‐sites to facilitate Na + transport. This work uncovers the role of cation‐π interactions in confined channels, offering a chemical design principle for selective ion‐channel membranes.

Source: Small

DOI: 10.1002/smll.76673