Page 459 - Organic Electronics in Sensors and Biotechnology

Ag electrode
PDMS
Microchannel
P3HT Vds
Solid
electrolyte Gnd
Glass Vg
5 V

≥0 V

Oxidized
P3HT
Neutral
P3HT
a
b
c

FIGURE 11.5 Top left: P3HT-based surface wettability switches used to
control the fl ow of aqueous samples in microfl uidic systems. Bottom left:
Water is transported relatively faster along the microchannel of the
Y-branches that include a fl oor of P3HT switched to the oxidized state
(c). Once the water approaches the neutral P3HT (red color), it slows down
considerably (a and b). Right: Electronic control of the gating of aqueous
samples can be used in various lab-on-a-chip technologies to enable
multiplexing of the sample analyte and different reagents. (From Ref. 13.
Reproduced by permission of the Royal Society of Chemistry, 2006.)

PEDOT PSS
O O n
S n
H
SO 3
FIGURE 11.7 Left: Chemical structure of PEDOT and PSS. Middle: The conjugated
PEDOT:PSS-based ion pump made of patterned, adjacent PEDOT:PSS electrodes
+
(A through D). Right: By addressing the electrodes ions (M ) migrate from the source
to the target electrolytes through the nonconducting PEDOT:PSS channel (pink).
160 5
10 s 20 s 30 s 40 s 150 0 s
+ – 140 10 s 4
20 s
V AB V CD Green intensity (arb. units) 130 30 s Approximate pH
+
–
50 s 60 s 90 s 120 s 40 s
50 s
60 s
180 s
+ – 120 120 s 3
240 s
180 s 240 s 300 s 360 s 110
V BC
1 2 3 4 5
Distance (mm) from release line
FIGURE 11.8 Left: The electronic ion pump with a pH paper on the C electrode as
an indicator of the proton gradient. Middle: The proton gradient formed over time.
Right: The associated measured pH gradients versus time. (Reprinted from Ref.
20. Copyright 2008, with permission from Elsevier.)