Biomedical Engineering Reference
In-Depth Information
2000
(a)
(b)
200nm
200nm
1500
1000
200nm
200nm
500
0
0
50
100
150
200
Charge (mCcm
-2
)
Ti(IV) oxide electrodeposition thickness calibration
measurements and film contraction on high temperature annealing.
(a) Example series of cross-sectional SEM images taken of gyroid film
replication with 5, 10, 20, 30 mC cm
Figure
2.22
charge passed through the porous
template in order to calibrate the deposition thickness. The first image is
of a film heated to 500
-2
°
C, showing additional material left from the empty
template region. (b) Plot of deposition thickness (
) for
nontemplated deposition before heating (
•
) and after annealing at 500
d
) versus charge (
Q
°
C
with a
37 ± 6% compression on heating. The equivalent plot for gyroid templated
arrays (
(
∘
). The deposition efficiency (
η
=
d
/
Q
) is 5.2 ± 0.2 nm/mCcm
-2
▴
▵
and a
40 ± 12% compression on heating. The straight lines are linear fits to
the data.
,
) gives a deposition efficiency of 10 ± 1 nm/mCcm
-2
(a)
(b)
50
200nm
overgrowth
40
30
20
10
0
substrate
0
1000
2000
3000
4000
Time (s)
Example of template filling by monitoring electrochemical
current. (a) Anodic current density in a 780 nm template. The current
increases by a factor of ∼1.8 on filling of the polymer template (accounting
for the steady fall in current with a single exponential decay fit). (b) Cross
section of templated array after removal of PFS matrix by UV-ozone etching
shows the uniform layer of overgrowth over the template surface.
Figure 2.23
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