Briesemeister Marcio, Gómez-Sánchez John A, Bertemes-Filho Pedro, Pezzin Sérgio Henrique
Department of Materials Science and Engineering, Santa Catarina State University, Joinville 89219-710, Brazil.
CalipYuk Entreprises, Bogota 110110, Colombia.
Polymers (Basel). 2024 Oct 10;16(20):2867. doi: 10.3390/polym16202867.
Due to their mechanical robustness and chemical resistance, composite electrospun membranes based on polyvinyl chloride (PVC) are suitable for sensor applications. Aiming to improve the electrical characteristics of these membranes, this work investigated the effects of the addition of carbon nanotubes (CNTs) to PVC electrospun membranes, in terms of morphology and thermal and impedance behavior. Transmission electron microscopy images evidenced that most of the nanotubes were encapsulated within the fibers and oriented along them, while field-emission scanning electron micrographs revealed that the membranes consisted of uniform fibers with an average diameter of 339 ± 31 nm, regardless of the addition of the carbon nanotubes. With respect to the neat resin, the addition of nanotubes caused a significant lowering of the glass transition temperature (up to 20 °C) and a marked change in the second degradation step of PVC. Nyquist plots from electrical impedance spectra showed a charge transfer resistance (R) of 38 and 40 MΩ for neat PVC and PVC/CNT 3 wt.% membranes, respectively, indicating that, in the dry state, the encapsulation of CNTs in the fibers and the high porosity of the membranes prevented the formation of a percolation network, increasing the electrical resistance. In the wet state, however, there was a greater change in the impedance behavior, decreasing the resistance R to 4.5 and 1.1 MΩ, for neat PVC and PVC/CNT 3 wt.% membranes, respectively. The results of this study, showing a significant variation in impedance behavior between dry and wet membranes, are relevant for the development of various types of sensors based on PVC composites.
由于其机械强度和耐化学性，基于聚氯乙烯（PVC）的复合电纺膜适用于传感器应用。为了改善这些膜的电学特性，本工作研究了向PVC电纺膜中添加碳纳米管（CNT）对其形态、热行为和阻抗行为的影响。透射电子显微镜图像表明，大多数纳米管被包裹在纤维内部并沿纤维方向排列，而场发射扫描电子显微镜照片显示，无论是否添加碳纳米管，膜均由平均直径为339±31 nm的均匀纤维组成。与纯树脂相比，添加纳米管导致玻璃化转变温度显著降低（高达20°C），并且PVC的第二步降解发生明显变化。电阻抗谱的奈奎斯特图显示，纯PVC膜和3 wt.% CNT的PVC/CNT膜的电荷转移电阻（R）分别为38和40 MΩ，这表明在干燥状态下，纤维中CNT的包裹和膜的高孔隙率阻止了渗流网络的形成，增加了电阻。然而，在潮湿状态下，阻抗行为有更大变化，纯PVC膜和3 wt.% CNT的PVC/CNT膜的电阻R分别降至4.5和1.1 MΩ。本研究结果表明干膜和湿膜的阻抗行为存在显著差异，这对于基于PVC复合材料的各种类型传感器的开发具有重要意义。
