Towards Sustainable Temperature Sensor Production through CO₂-Derived Polycarbonate-Based Composites

The steep increase in carbon dioxide (CO₂) emissions has created great concern due to its role in the greenhouse effect and global warming. One approach to mitigate CO₂ levels involves its application in specific technologies. In this context, CO₂ can be used for a more sustainable synthesis of polycarbonates (CO₂-PCs). In this research, CO₂-PC films and composites with multiwalled carbon nanotubes (MWCNTs, ranging from 0.2 to 7.0 wt.%) have been prepared to achieve more sustainable multifunctional sensing devices. The inclusion of the carbonaceous fillers allows for the electrical conductivity to be enhanced, reaching the percolation threshold (P_c) at 0.1 wt.% MWCNTs and a maximum electrical conductivity of 0.107 S·m^-1 for the composite containing 1.5 wt.% MWCNTs. The composite containing 3.0 wt.% MWCNTs was also studied, showing a stable and linear response under temperature variations from 40 to 100 °C and from 30 to 45 °C, with a sensitivity of 1.3 × 10^-4 °C^-1. Thus, this investigation demonstrates the possibility of employing CO₂-derived PC/MWCNT composites as thermoresistive sensing materials, allowing for the transition towards sustainable polymer-based electronics.