3.2.2. ICEO micromixer
Following the suggestion of Squires and Bazant (Bazant & Squires, 2004;
Todd M Squires & Bazant, 2004) on demonstrating the capability of MVs
generated around polarizable objects for ICEO mixing, Harnett et al.
(Harnett et al., 2008) proved this capability numerically and
experimentally. A numerical model was developed to determine optimal
design parameters of ICEO mixing followed by fabricating the optimal
design array of gold-coated hurdles of the triangular cross-section in
microchannels under a low-frequency AC field applied on the sidewalls. A
rapid increase in mixing from zero to almost perfectly mixed state
(100%) in a small length scale was demonstrated (Fig. 3A ).
Wu and Li (Z. Wu & Li, 2008b) further simplified the design
configuration to a triangle conducting hurdle pair on microchannel walls
while enhanced the mixing performance. They optimized the system
parameters and demonstrated 92% mixing efficiency. It was shown that
the rectangular conducting objects placed on the microchannel walls
generated the highest mixing efficiency (Fig. 3B ).
Nevertheless, Jain et al. (Jain, Yeung, & Nandakumar, 2009) showed that
a pair of near tight triangle hurdle present even a better mixing
performance as 99% efficiency. The performance of various ICEO
micromixers developed so far are highlighted in Table 2 .
The ICEK Micromixers have become popular for LOC applications due to
their mixing efficiency (above 90%), simplicity and rapid mixing.
However, the majority of studies are still limited to numerical studies
to optimize electrodes shape and arrangement. Further experimental
studies are needed to evaluate the performance of proposed mixing
systems. Among various designs, the model of Daghighi and Li (Daghighi
& Li, 2013) (Fig. 3C ) is attractive due to its simple
structure and straightforward fabrication method (Kazemi, Nourian,
Nobari, & Movahed, 2017; M. K. D. Manshadi et al., 2019; Shamloo,
Madadelahi, & Abdorahimzadeh, 2017). Further experimental
characterization on this design configuration would guarantee an
affordable and scalable technique for high-performance ICEK mixing
within microfluidics.