Carbon nanotubes for optimizing response stability and speed of acrylate hybrid copolymers humidity sensor

Carbon nanotubes (CNTs) are one-dimensional nanomaterials with a hollow structure, high specific surface area and excellent chemical conductivity, which show great potential for application in the field of humidity-sensitive responsive materials and humidity sensors. In this paper, CNTs were composited with a hybrid copolymer (HAC) of octavinyl POSS/acrylate to prepare the hybrid copolymer composites HAC/CNTs and their humidity sensors, which demonstrated exceptional thermal stability and fast response speed. Among them, acrylic resin serves as a humidity-sensitive material; POSS introduce a stable three-dimensional cage skeleton structure to the material; and CNTs are used as conductive fillers, which further enhance the stability of the material, as well as improve the sensitivity and humidity-sensitive response speed of the material. The experimental findings indicate that the HAC/8.0% CNTs composite material exhibits a remarkable sensitivity of 119.94 K Omega/%RH within the humidity range of 11%-95%RH. Compared with HAC, HAC/8.0% CNTs demonstrate a significant reduction in response/recovery time from 16.0 s/70.0 s to 0.8 s/80.0 s, representing a considerable improvement in response speed; the wet hysteresis is reduced from 0.88 %RH to 0.77 %RH; and the temperature change coefficient is reduced from 0.035 %RH/degrees C to 0.008 %RH/degrees C over the temperature range of 20-60 degrees C, indicating superior stability against temperature variation. Meanwhile, the humidity response mechanism of HAC/CNTs was discussed by using complex impedance spectrum. The hybrid copolymer composites, HAC/CNTs, that were prepared in this study have tremendous potential in the development of advanced, high-performance, and miniaturizable humidity sensing technologies.Highlights A hybrid copolymer composite humidity-sensitive material HAC/CNTs is prepared. HAC/CNTs are compounds consisting of CNTs and POSS/acrylate hybrid copolymer. POSS improve the skeleton structural stability of acrylic resins. CNTs enhance the sensitivity and response speed of humidity sensor. The HAC/8.0% CNTs have higher response stability and faster response speed. Schematic diagram of HAC/CNTs humidity-sensitive device and humidity-sensing process. image