This article presents the implementation of on-chip iontronic circuits via
small-scale integration of multiple ionic logic gates made of bi-polar
polyelectrolyte diodes. These ionic circuits are analogous to solid-state
electronic circuits, with ions as the charge carriers instead of
electrons/holes. We experimentally characterize the responses of a single
fluidic diode made of a junction of oppositely charged polyelectrolytes (i.e.,
anion and cation exchange membranes), with a similar underlying mechanism as a
solid-state p- and n-type junction. This served to carry out pre-designed
logical computations in various architectures by integrating multiple
diode-based logic gates, where the electrical signal between the integrated
gates was transmitted entirely through ions. The findings shed light on the
limitations affecting the number of logic gates that can be integrated, the
degradation of the electrical signal, their transient response, and the design
rules that can improve the performance of iontronic circuits