The role of polyelectrolyte brushes in tunable synaptic devices

TL;DR

This paper demonstrates that polyelectrolyte brushes can exhibit synaptic behavior in simple electrochemical devices, providing insights into their role and response mechanisms, which aids in designing polymer-based neuromorphic systems.

Contribution

It shows the synaptic capabilities of polyelectrolyte brushes in simple devices and combines theory and experiments to understand their dynamic response mechanisms.

Findings

Polyelectrolyte brushes exhibit synaptic behavior in simple electrochemical cells.

Brush response depends on salt concentration and polarity changes.

The study provides a foundation for polymer brush-based neuromorphic device design.

Abstract

With the ever-increasing digitization of society, the development of materials with low-power memory storage -similar to synapses- is becoming more relevant. The field of iontronic artificial synapses has gained traction, in particular with polymers as the memory-active material which allows for additional bio-compatibility, flexibility and tunability. Polyelectrolyte brushes are an example of stimulus-responsive materials that can be used in iontronic devices. However, the complexity of current neuromorphic devices does not allow us to isolate and understand the role of polyelectrolyte brushes in their synaptic response. In this paper, we show that polyelectrolyte brushes are capable of synaptic behavior in the most simple of electrochemical cell designs. Furthermore, by combining theory and experimental work, we shed light on the role of brushes in this synaptic behavior and their dynamic stimuli-responsiveness to polarity changes for different salt concentrations. The obtained trends and interpretations of the nonlinear potential-current response, paired-pulse experiments, and accumulative learning lay the foundation for designing and developing polymer brush-based neuromorphic devices.