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9-34 MEMS: Design and Fabrication

200
180
160
140
Pull-in voltage (V) 120 Predicted V

100
80

60
10 × 2 cell with
epoxy assembly
40
12.5 × 2 cell with
20
tape assembly
0
0 1 2 3 4 5 6 7 8
Mass (g)

FIGURE 9.33 Experimental vs. theoretical pull-in voltage vs. load for the biomimetic MEMS actuator cell for two
assembly techniques (after Horning and Johnson (2002)).

+
Al V
−

(a) Silicon (d) Polyimide

Silicon

Polyimide
Al Top view
(b)
Silicon Polyimide

Polyimide
SAW
(c)
Silicon

FIGURE 9.34 (See color insert following page 9-22.) SAW fabrication on electroactive polyimide (after Atkinson
(2003)).

shows a cross-sectional photograph of a photograph of a fabricated actuator that has been pulled open,
and Figure 9.32(b) shows the actuator after a voltage has been applied and the actuator has collapsed. Figure
9.33 shows a measurement of the pull-in voltage as a function of the external load, where an improved
fabrication technique improved considerably the match with the theoretically predicted results.

9.4.4 Surface Acoustic Wave Devices in Polymers

An interesting use of electroactive polymers in sensor applications is to apply them to surface acoustic
wave (SAW) devices. For an excellent review, the reader is referred to Varadan and Varadan (2000). One

© 2006 by Taylor & Francis Group, LLC