Reconfigurable Nanofluidic Synapses Based on Polyaniline Protonation-Deprotonation Chemistry for Potential Bio-Integrated Computing

Abstract

Polyaniline (PANI) has been extensively studied for decades, yet its reversible protonation-deprotonation (PDP) chemistry has remained unexploited in nanofluidic neuromorphic computing. Here we show that a porous PANI membrane, prepared by simple spin-coating, functions as a volatile ionic synapse whose short-term plasticity is chemically reconfigurable. Acid and base treatments reversibly switch the same device between paired-pulse facilitation and paired-pulse depressionopposing forms of synaptic behaviorthereby achieving chemically reconfigurable plasticity. Taking the base-configured state as a model system, the device exhibits spike-frequency, spike-amplitude, spike-duration, and spike-number dependent plasticity, revealing rich temporal dynamics. When integrated into a reservoir computing framework for handwritten digit recognition, this synaptic element achieves a classification accuracy exceeding 90%. Our work repositions PANI from conventional electrochemistry to reconfigurable nanofluidic synapses, where its PDP chemistryonce merely governing conductivity and surface chargenow enables history-dependent ionic dynamics under nanoconfinement. This convergence of classical polymer chemistry with neuromorphic iontronics establishes an unexpected materials platform for aqueous-based, bio-integrated computing systems.