posted on 2022-05-24, 16:10authored byCuiwen Liu, Ru Zhang, Peiwen Li, Jinqing Qu, Pengjie Chao, Zongwen Mo, Tao Yang, Ning Qing, Liuyan Tang
Hydrogel
strain sensors with extreme temperature tolerance have
recently gained great attention. However, the sensing ability of these
hydrogel strain sensors changes with temperature, resulting in the
variety of output signals that causes signal distortion. In this study,
double-network hydrogels comprising SiO2 nanoparticles
composed of polyacrylamide and phytic acid-doped polypyrrole were
prepared and applied on strain sensors with a wide sensing range,
high adhesiveness, and invariable strain sensitivity under flame and
cold environments. The hydrogels had stable conductivity, excellent
adhesive strength of up to 79.7 kPa on various substrates, and high
elongation of up to 1896% at subzero temperature and after heating.
They also exhibited effective flame retardancy with low surface temperature
(71.2 °C) after 1200 s of heating (200 °C) and antifreezing
properties at a low temperature of −20 °C. Remarkably,
even under cold temperature and heat treatment, the hydrogel-based
strain sensor displayed consistent sensing behaviors in detecting
human motions with a broad strain range (up to 500%) and steady gauge
factor (GF, ∼2.90). Therefore, this work paves the way for
the applications of hydrogel sensors in robotic skin, human–mechanical
interfaces, and health monitoring devices under harsh operating environments.