Direct imaging elucidates ionic memory in two-dimensional nanochannels

Kalluvadi Veetil Saurav; Nathan Ronceray; Baptiste Coquinot; Agustin D. Pizarro; Ashok Keerthi; Theo Emmerich; Aleksandra Radenovic; Boya Radha

arXiv · 2509.11637

Direct imaging elucidates ionic memory in two-dimensional nanochannels

Kalluvadi Veetil Saurav·Nathan Ronceray·Baptiste Coquinot·Agustin D. Pizarro·Ashok Keerthi·Theo Emmerich·Aleksandra Radenovic·Boya Radha

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Abstract

Nanofluidic memristors promise brain-inspired information processing with ions, yet their microscopic origin remains debated. So far, ionic memory has been attributed to ion-specific interactions, dynamic wetting, chemical reactions or mechanical deformations, yet typically without direct experimental evidence. Here, by combining operando interferometric imaging with electrokinetic measurements, we directly visualize voltage-induced blistering of the confining walls of two-dimensional (2D) nanochannels, as key origin of memristive hysteresis. We identify two distinct classes of blisters: unidirectional, driven by electrostatic forces on surface charges, and bidirectional, arising from osmotic pressure due to concentration polarization. This mechanistic framework explains device evolution and device-to-device variability, and reframes stochastic blistering as a functional design element. Our results constitute a direct proof of electromechanical coupling as a robust pathway to ionic memory in 2D nanochannels and open routes toward high-performance ionic memristors and electrically actuated nanofluidic valves.

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Kalluvadi Veetil Saurav, Nathan Ronceray, Baptiste Coquinot, Agustin D. Pizarro, Ashok Keerthi, Theo Emmerich, Aleksandra Radenovic, Boya Radha. 2025-09-15. Direct imaging elucidates ionic memory in two-dimensional nanochannels. https://arxiv.org/abs/2509.11637

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