High-Performance
Mechano-Sensitive Piezoelectric Nanogenerator
from Post-Treated Nylon-11,11 Textiles for Energy Harvesting and Human
Motion Monitoring
Piezoelectric polymer textiles offer distinct advantages
in the
fabrication of wearable nanogenerators (NGs). One effective strategy
to enhance the output capacity of NGs is to modulate the piezoelectric
performance of the textiles. This paper focuses on further improving
the piezoelectric properties of nylon-11,11 textiles through post-drawing
and annealing treatments. We elucidate the evolution of morphology
and the ferroelectric phase in the submicron/nanoscale fibers during
post processing as well as the corresponding changes in performance.
The drawing process primarily enhances the orientation of the crystalline
phase and reduces the fiber diameter, while the annealing process
more effectively promotes the crystal size and crystallinity. Afterward,
we propose an optimal postdrawing and annealing assisted-electrostatic
spinning process. Under the synergistic effects of these post-treatments,
the remanent polarization (Pr) of nylon-11,11
textile increased to 4.7 times that of the untreated textile, resulting
in amplified piezoelectric outputs. The output voltage, current, and
power density of the prepared PENG reached 21.5 V, 800 nA, and 1.88
mW·m–2 (80 MΩ), respectively. Notably,
at pressures exceeding 8 kPa, the mechano-voltage and current sensitivity
reached as high as 266 mV/kPa and 13.99 nA/kPa, respectively, which
is extraordinary compared to other piezoelectric NGs and comparable
to the performance of nylon-based triboelectric NGs. Furthermore,
we investigated the potential application of the prepared PENG in
biomechanical energy harvesting and human movement monitoring. Experiments
demonstrated its effectiveness in powering light bulbs, tracking walking
status, and monitoring finger/hand/wrist gestures.