el1c00372_si_001.pdf (634.85 kB)
Ingestible, Biofriendly, and Flexible Flour-Based Humidity Sensors with a Wide Sensing Range
journal contribution
posted on 2021-06-11, 15:04 authored by Shijie Hou, Yukuan Shen, Yan Wang, Xuan Zhang, Wei Luo, Jia HuangEcofriendly
and biofriendly materials are highly appealing in electronic
devices with the booming development of the Internet of Things. Humidity
sensors perform an indispensable role in various fields such as monitoring
industry processes and living systems. In this contribution, for the
first time, edible and abundant material-flour has been introduced
to the sensing layers for humidity detection. The ionic conductive
K2CO3 and hygroscopic glycerol (Gly) with biosafety
were introduced to the sensing layer to promote a humidity sensing
capability and long-time stability. The ingestible Gly-K2CO3 flour-based humidity sensor using PLA as substrates
displays an excellent sensing performance and wide humidity detecting
range. Good linearity between capacitance and relative humidity (RH)
has been achieved for the RH range from 6% to 94%. According to a
wireless monitoring system, even at 250 kHz, the sensor can still
monitor the nuance of the humidity difference between 40% and 43%
and exhibited an ultrafast response time (0.3 s) and recovery time
(0.7 s). Furthermore, the consistent and stable sensing performance
after long-time measurements for 100 days and bending tests for 500
cycles also demonstrated a long-time humidity detecting stability
and mechanical flexibility for the Gly-K2CO3 flour-based humidity sensor. Humidity sensing mechanisms were thoroughly
investigated through SEM-EDX, FTIR, XPS, and complex impedance spectroscopies.
The enhanced sensing performance, wide humidity detecting range, and
long-time stability are attributed to the ionic conductivity from
K2CO3 and the hydrogen-bond interaction between
H2O and enormous hydrophilic groups, such as hydroxyl and
amino groups in the flour-based networks and binary solvent.
History
Usage metrics
Categories
Keywords
XPSmonitoring systemHumidity sensorsGood linearityhumidity differenceingestible Gly-K 2 CO 3 flour-based...Range EcofriendlyGly-K 2 CO 3 flour-based humidity s...100 daysFlexible Flour-Based Humidity Sensorssubstrates displaysconductive K 2 CO 3FTIRflour-based networksH 2 O250 kHzRH rangehumidity detectionPLAhydrogen-bond interactionimpedance spectroscopies500 cyclesmonitoring industry processeshygroscopic glycerolK 2 CO 3SEM-EDXbiofriendly materials