  The most common method to characterize the electrical response of a
nanofluidic system is through its steady-state current-voltage response. In
Part I, we demonstrated that this current-voltage response depends on the
geometry, the layout of the surface charge, and the effects of advection. We
demonstrated that each configuration has a unique steady-state signature. Here,
we will elucidate the behavior of the time-transient response. Similar to the
steady-state response, we will show that each configuration has its own unique
time-transient signature when subjected to electroosmotic instability. We show
that bipolar systems behave differently than unipolar systems. In unipolar
systems, the instability appears only at one end of the system. In contrast, in
bipolar systems the instability will either appear on both sides of the
nanochannel or not at all. If it does appear on both sides, the instability
will eventually vanish on one or both sides of the system. In Part I, these
phenomena were explained using steady-state considerations of the behavior of
the fluxes. Here, we will examine the time-transient behavior to reveal the
governing principles that are, on the one hand, not so different from unipolar
systems and, on the other hand, remarkably different.
