advances.sciencemag.org/cgi/
content/full/6/40/eaay9842/DC1
Supplementary Materials for
Wireless battery-free wearable swe
at sensor powered by human mo
tion
Yu Song, Jihong Min, You Yu, Haobin Wang, Yiran Yang, Haixia Zh
ang, Wei Gao*
*Corresponding author. Email: weigao@caltech.edu
Published 30 September 2020,
Sci. Adv.
6
, eaay9842 (2020)
DOI: 10.1126/sciadv.aay9842
This PDF file includes:
Figs. S1 to S25
Notes S1 and S2
Tables S1 and S2
References
Fig. S1. Fabrication process of the slider and the stator of the FTENG.
Steps (i-vi) are
compatible to the commercial FPCB fabrication process.
(iv) Etched by FeCl
3
solution
(ii) Spin
-coating photoresist
(i) Copper clad laminate
(iii) Photolithography
(v) Photoresist removal
(vi) ENIG deposition
Polyimide
Copper
Photoresist
ENIG
(vii) PTFE coating
PTFE
Slider
Stator
Fig. S2. Structure and parameters of the FPCB-based FTENG with an interdigital stator and
a grating slider.
W1
W2
L1
L2
d1
h1
d2
g2
h2
g1
Length (mm)
Dimension of FTENG
37.8
59.8
1.8
0.2
Stator
W1
L1
d1
g1
Slider
W2
L2
d2
g2
Length (mm)
43.6
41.8
1.8
2.2
1.8
h1
h2
1.8
Slider
Stator
Fig. S3. Theoretical model and transferred charge density studies of FTENGs.
(
A
) The
theoretical model of FTENG. (
B
–
F
) The simulated transferred charge densities at different sliding
displacements of 5 FTENGs with varied inter-electrode distances.
0.0
0.8
1.6
2.4
3.2
0
20
40
60
80
Δ
σ
SC
(μC/m
2
)
x
(mm)
0.0
0.7
1.4
2.1
2.8
0
20
40
60
80
Δ
σ
SC
(μC/m
2
)
x
(mm)
0.0
0.9
1.8
2.7
3.6
0
20
40
60
80
Δ
σ
SC
(μC/m
2
)
x
(mm)
A
D
E
F
0.0
0.5
1.0
1.5
2.0
0
20
40
60
80
Δ
σ
SC
(μC/m
2
)
x
(mm)
0.0
0.6
1.2
1.8
2.4
0
20
40
60
80
Δ
σ
SC
(μC/m
2
)
x
(mm)
B
C
g
= 2 mm
g
= 6 mm
g
= 18 mm
g
= 14 mm
g
= 10 mm
Electrode A
Electrode B
Slider
g
PTFE
x
σ
= 80 μC m
-2