Impact of Surface Modification via Plasma Treatment on the Response of Strain Sensor Based on MWCNTs/epoxy Nanocomposite

摘要

Strain sensor based on MWCNTs/epoxy nanocomposite are attracting the attention of many researchers not only because they have low cost, but also because of the high sensitivity comparing to the conventional strain sensor due to the piezoresistive behavior under load. In this study, the objective is to achieve higher sensing sensitivity by enhancing the stress transfer between thin film/Substrate. To this aim, polyimide substrate was exposed to oxygen plasma treatment in order to activate and enhance the surfaces prior deposition of the MWCNTs/epoxy nanocomposite thin film. In fact, exposure time was varied 2, 4, 5, 10 min in order to investigate the impact on the electro-mechanical response. For deeply investigation, Atomic Force Microscopy (AFM) was used to examine the topography of the modified surfaces of the kapton HN by measuring the root-mean-squared (RMS) roughness. The AFM results show that the root-mean-squared (RMS) roughness of pristine PI film was 2.5 nm, increasing to 15.5 nm after 4 minutes oxygen plasma treatment. Furthermore, Raman spectroscopy was used to follow the changes on the molecular structure of surface following treatment time. A higher sensitivity was achieved after 4 min plasma with a gauge factor around 13.6.