banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
Microfluidic pumps employing surface acoustic waves generated in ZnO thin films
Rent this article for


Image of FIG. 1.
FIG. 1.

Schematic drawing of interaction between surface acoustic wave and a liquid droplet and defining the Rayleigh angle, .

Image of FIG. 2.
FIG. 2.

Acoustic force as a function of rf signal voltage acting on a water droplet for both a (Ref. 42) and ZnO SAW device. The device uses a Rayleigh mode wave, while the ZnO device uses a Sezawa mode wave. Both devices have 60 finger pairs in the IDT.

Image of FIG. 3.
FIG. 3.

Photos of a droplet on an untreated and an OTS treated ZnO surface. The contact angle increased from to 110° after OTS SAM layer formation.

Image of FIG. 4.
FIG. 4.

Variation in minimum acoustic force, , required to move a water droplet of volume on a surface as a function of contact angle calculated from Eqs. (6) and (7).

Image of FIG. 5.
FIG. 5.

Photos of a droplet movement on an OTS treated ZnO SAW device before (a) and after (b) being driven by a rf signal at a frequency of 178.7 MHz.

Image of FIG. 6.
FIG. 6.

Sezawa wave driven droplet velocity as a function of rf signal voltage applied on the SAW for a ZnO SAW device.

Image of FIG. 7.
FIG. 7.

Total distance moved by a water droplet as a function of pulse number for a rf signal of 40 V and a pulse width of 100 ms.

Image of FIG. 8.
FIG. 8.

Schematic drawing of the proposed SAW structure with ZnO on the wave path being removed compared with the standard SAW device structure where the ZnO is not patterned.

Image of FIG. 9.
FIG. 9.

Comparison of transmission spectra for SAW devices before and after removal of the ZnO from the propagation area using (a) the Rayleigh wave from a thick ZnO thin film and (b) the Sezawa wave from a thick ZnO thin film.

Image of FIG. 10.
FIG. 10.

Streaming velocity induced by acoustic waves from the SAW devices where there is no ZnO in the propagation region. Results for both Sezawa (s) and Rayleigh (r) mode devices are presented.

Image of FIG. 11.
FIG. 11.

Temperature change as a funciton of time with rf signal voltage as a parameter. The temperature rises rapidly at the initial 20 s, and then increases slowly thereafter.


Generic image for table
Table I.

Extracted parameters for the acoustic force extraction.


Article metrics loading...


Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Microfluidic pumps employing surface acoustic waves generated in ZnO thin films