  This research paper presents a 2D numerical model of an electrokinetic
T-junction micromixer based on the stretching and folding theory presented by
Ottino. Particle deformation was considered by simulating 2 $\mu m$ massless
particles as 8-point square cells. Furthermore, stretching and folding
definitions are proposed, compatible with a Lagrangian particle approach.
Moreover, mixing homogeneity and consistency were measured in a 200 $\mu m$
square region of interest neighboring the outlet. Statistical analysis of the
exiting mixing homogeneity at four different electric field conditions (93.5
V/cm, 109.8 V/cm, 126 V/cm and 117.9 V/cm, corresponding to a 23V, 27V, 29V and
31V potential difference) show that mixing consistency and homogeneity are not
always increased with a higher electric field intensity, even after
electrokinetic instabilities are formed, as increasingly unstable flow
conditions decrease the ratio of folding to stretching ($m$), hindering the
interaction between substances. Finally, an optimal proportion of stretching to
folding was found for maximizing mixing efficiency at $m =0.0045$.
