With the development of the internet of things technology, sensors have played an important role in aerospace, industry, agriculture, medical and other fields. Especially in the aspect of wearable respiratory monitoring, real-time monitoring of multiple respiratory physiological parameters through intelligent sensors enable people to achieve early prevention and timely diagnosis of respiratory diseases. However, most of the humidity sensors have the disadvantages of poor permeability, long response time and narrow detection range. Therefore, this paper introduced a flexible humidity sensor with a wide detection range and fast response time for respiratory monitoring. The sensor used PEDOT:PSS-GO composite material as humidity sensitive material. Due to the addition of GO, the sensor had a wide linear detection range of humidity (35–80%RH) and a short response/recovery time (0.53/0.8 s). Moreover, the sensor used the micromesh structure of PI as the substrate, which had better flexibility and permeability and the sensor was easy to attach to complex surfaces such as masks or human skin. Based on these excellent sensing characteristics, the humidity sensor was connected with a miniature wireless communication component for human respiratory detection. The humidity sensor can clearly show the difference between normal and abnormal respiratory signals and this provided a new idea for the intelligent healthcare technology.
Carbon nanotubes (CNTs) and graphene oxide (GO) were sprayed on flexible polyethylene terephthalate (PET) substrates to prepare CNT and GO–CNT transparent conductive films (TCFs). For the GO–CNT TCFs, when the mass ratio of GO to CNTs was 0.2, a relatively low sheet resistance of 90.4 Ω sq−1 at a transmittance of 87% (550 nm) was obtained with an average σdc/σopt value of 28.9. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) solution without or with ethylene glycol (EG) added was sprayed on the surface of the GO–CNT films to obtain P/GO–CNT and P(E)/GO–CNT films, respectively. P(E)/GO–CNT films were post-treated with sulfuric acid to obtain P(E,S)/GO–CNT TCFs. The addition of PEDOT:PSS can permeate into the pores of networks and densify the GO–CNT networks, increasing the conductivity and wettability and decreasing the roughness of the films. Additional EG can reduce the Coulomb force between PEDOT and PSS and change the morphology of PEDOT, and at the same time sulfuric acid treatment can effectively remove PSS from the PEDOT:PSS layer. The P(E,S)/GO–CNT 0.2 TCFs exhibited a sheet resistance of 46.3 Ω sq−1 at a transmittance of 87.5% (550 nm) with an average σdc/σopt value of 56.1. The organic light emitting diodes were successfully fabricated, and the mechanism of how the electrical conductivity of the hybrid film increased was also investigated.
危险品化学品经营许可证（带存储）