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Real-Time, Wearable, Bio-Mechanical Movement-

Capture of Both Humans and Robots with Metal-

Free Electrodes

Priya Rathia, Mihir Kumar Jha

a, Kenji Hata

b, Chandramouli Subramaniam

a*

aDepartment of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076,

Maharashtra, India

bDirector, Nanotube Research Center, National Institute of Advanced Industrial Science and

Technology (AIST) Tsukuba, Japan 305 – 8565.

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Figure S1. Transmission spectrophotometric investigation of CNT-PDMS strip. (a) Transmission

spectra for pure PDMS and varying concentration loadings of CNTs in PDMS. (b) Variation in

transmittance with CNT loading concentration at 420nm.

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Figure S2. Investigation of CNT-thread. (a) SEM image of uncoated, pure cellulose thread.

(b) SEM image of CNT-coated thread. (c) SEM image showing the uniform distribution of

interconnected CNTs when coated on thread. (d) TEM image of the CNTs.

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Figure S3. Conductivity studies on CNT-thread. (a) Circuit setup to light up an LED using

CNT-threads as connecting wires. (b) Current-voltage characteristics of uncoated thread and

CNT-thread. Invariant response of the CNT-thread due to bending and twisting.

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Figure S4. Site specific device response. Signal response generated at distinct joints

corresponding to the extent of permissible bending at the joint.

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Figure S5. Iodine doping for X-ray mapping. X-ray photoelectron spectra indicating the

presence of (a) C1s peak and (b) I3d.

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Figure S6. (a), (b) Optical images of the device showing the morphology and distribution of

CNTs throughout the PDMS matrix.

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Figure S7. Confocal three-dimensional spectro-microscopy. Confocal spectral maps acquired

through micro-Raman confocal depth profiling, for a depth of 10 µm at 1µm depth gap.

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Figure S8. Confocal image processing and electron microscopy of CNT-PDMS strip. (a)

Confocal laser scanning microscopy images for a three-dimensional volume element analysed

to form two-dimensional binary black and white images. (b) SEM image indicating

homogeneity and uniformity of CNT-PDMS strip.

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Table S1. Quantification of CNT distribution. Confocal laser scanning depth analysis from

two-dimensional binary black and white images. The ratio of black shaded area to total area

of the sample with the depth of the sample analysed gave a measure of the CNT coverage.

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Figure S9. Mechanical properties and cyclability of the device. (a) Variation of Young’s

modulus and ultimate tensile strength with CNT loading concentration. (b) Signal generated

by device, fabricated using shorter length of CNT-thread, upon repeated cyclic testing. (c)

Signal response of device for 10 such cycles.