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

Abstract

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 KΩ/%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/°C to 0.008 %RH/°C over the temperature range of 20–60°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.