Labram hr evolution spectrometer

The SEM characterization was accomplished using a JEOL JSM-7001F FE-SEM. Raman spectra were recorded on a HORIBA LabRAM HR Evolution spectrometer. XRD characterization was performed on Rigaku D/max 2550 with Cu Kα radiation (λ = 1.54°). In addition, the yarn was sputter coated with platinum before being examined by FE-FEM.
To facilitate measurement and reduce contact resistance, two copper pieces were pasted onto each end of the yarn using conductive silver paste before strain sensing tests. The electric properties of the smart yarns were measured by a Keithley 2510 source meter. The sensing performances were evaluated by a mechanical-electric coupling test including a universal testing machine (MTS E44.104 with 500 N load cell) and the source meter. The tension was controlled by the universal testing machine with the fixed deformation rate of 20 mm/min and real-time changes of the sensor resistance were recorded by the source meter programmed by LabVIEW. The sensing performance under other deformation rates was summarized in Supplementary Fig. S6, showing no frequency dependence.

XRD was carried out with
a PANalytical Empyrean X-ray platform using Cu Kα radiation
in θ–2θ geometry and an angular range from 2 to
70° in 0.02° steps. The sample was kept in a glass capillary
under ambient conditions.
Raman spectroscopy characterization
was carried out using a Horiba LabRam HR Evolution spectrometer, employing
a HeNe laser (632.8 nm). The laser was focused using a 100× objective
(0.8 NA), thus leading to a laser spot with a diameter of ca. 1 μm. An EMCCD camera was employed to collect
the backscattered light that was dispersed by an 1800 grooves per
mm grating providing a spectral resolution of ∼1 cm^–1. The corresponding Raman spectra were then constructed by processing
the data using Lab Spec 6 software.
For XPS measurements, a
TFS K-Alpha X-ray Photoelectron Spectrometer
(K-Alpha compact XPS) was employed. The powdered sample was glued
to a sample holder using carbon tape. The primary radiation source
was monochromatized Al Kα (1486.6 eV) using a spot size of either
200 or 400 μm. The base pressure for the measurement was 4 ×
10^–9 mbar. For survey spectra, the analyzer energy
and spectral resolution were set to 150 and 1 eV, respectively. High-resolution
spectra were acquired using an analyzer energy of 50 eV and a spectral
resolution of 0.1 eV.
Etching of the surface was carried out
with an Ar ion beam (2 kV,
7.8 μA) for 30 s, effectively removing the functionalized surface
layer.

The electronic environment of the samples were investigated through XPS (Phi5000 VersaProbe, Ulvac-Phi) with Al Kα radiation. All samples were sealed in a vacuum transfer chamber in the glove box and then transferred into the XPS equipment for measurement. Raman was conducted through the Horiba Scientific LabRAM HR Evolution Spectrometer. The wavelength of laser is 532 nm and the power is 5 mW.