Chemistry Reference
In-Depth Information
30
000
320
000
29
000
1
310
000
1
300
000
28
000
290
000
2
3
27
000
2
3
280
000
26
000
270
000
25
000
260
000
24
000
250
000
4
4
23
000
240
000
0
50
100
150
0
50
100
150
(a)
Time (h)
(b)
Time (h)
320
3200
310
1
2
3
3100
1
300
3000
2900
290
2
3
2800
280
2700
270
2600
4
260
2500
4
2400
250
0
50
100
150
0
50
100
150
(c)
Time (h)
(d)
Time (h)
9.15
Long-term stability tests of (1) palladium sheet electrodes and (2)
woven, (3) knitted and (4) non-woven textile electrodes, obtained
by measurement of
R
as a function of time in the electrochemical
cell for NaCl electrolyte concentrations of (a) 1
¥
10
-
4
, (b) 1
¥
10
-
3
,
(c) 1
¥
10
-
2
and (d) 1
¥
10
-
1
mol l
-
1
.
Experimental proof for the above-described hypothesis was found by
taking microscopic photographs of the textile structures in dry and wet con-
ditions using a fluorescent solution. From these images, it could be seen that
air bubbles were indeed trapped in the wet structures, but due to the more
regular structure of the non-woven fabrics compared with woven and
knitted fabrics, much less air was trapped. Confirmation for the dissolution
of these bubbles is found by the absence of air when the textile electrodes
were immersed for about 3 days in the fluorescent solution.
The decrease of resistance from
t
= 0 until an equilibrium condition is
obtained is about 20% for the woven structure and about 7% for the knitted
and non-woven structure, except for the highest electrolyte concentration
(1 ¥ 10
-1
mol l
-1
). In that case, the decrease is less pronounced. Extrapolation
of the onset of the curve (covering the first 2 days of the experiment)
showed that the equilibrium condition is obtained at about 10 W higher
than expected by this extrapolation. The cause of this can be found in a
