Figure 10 (a) Proof of Concept of Dual Network Thermoelectric
Hydrogel Respiratory Monitoring System with Mask Attached, Infrared
Image of Wearing Mask and Monitoring Results. Reprinted with permission
from ref. 19. Copyright 2022 American Chemical Society. (b) The tester
wore a headband with the sensor. The next is the response of the sensor
when cycling. Reprinted with permission from ref. 89. Copyright 2022
American Chemical Society. (c) Panoramic view of the gel-based
thermoelectric patch for body temperature monitoring. Relationship
between current and body temperature in the three typical regions. Body
temperature monitoring and the corresponding temperature signal are
displayed on terminals. Insets: Photographs of the gel patch that was
twisted and bent (scale bar: 1 cm). Reprinted with permission from ref.
20. Copyright 2021 American Chemical Society.
The thermoelectric gel patch
prepared by Zhang et al.,[19] as illustrated in
Figure 10a, effectively converted physiological data into
easy-to-understand electrical pulse signals by taking advantage of the
temperature difference between the environment and the heat generated by
human breathing. Interestingly, the gel patch functioned reliably even
in temperatures below 0 °C, implying its adaptability to low-temperature
environments. In another investigation, Zhang et al. developed a
highly-sensitive temperature sensor using thermoplastic polyurethane
fiber that can accurately monitor human activity. The sensor, with a
remarkable tensile strain of up to 270%, can be conveniently worn as a
headband to monitor the body temperature of athletes (Figure
10b).[89] Similarly, Yang et al. successfully
created a wearable temperature sensor using the oxidation-reduction
reaction mechanism of
[Fe3+/Fe2+]. The device
generated variable current signals in response to fluctuations in body
temperature, providing key information about the temperature status of
the wearer, as shown in Figure 10c. These research findings may have
significant relevance in monitoring human activity and predicting
potential health risks, making them valuable contributions to the
field.[20]In the latest progress, Zhang et al. introduced a thermogalvanic
interpenetrating network hydrogel with
[Fe(CN)6]3-/[Fe(CN)6]4-as a redox pair and KCl as a ion provider for thermodiffusion, which not
only has good flexibility but also prominent thermoelectric property
with the thermal current up to 124 μA at the temperature difference of
10 K. Committed to providing more effective medical assistance
services.[102]