Temperature Sensors on Recyclable Vitrimer Substrates

The increasing amount of electronic waste, predicted to reach 60 million tons by 2029, is one of the big health concerns for our society. This issue, together with plastic waste, represents the main environmental concern when dealing with large-area electronic devices and systems. The solution for this growing problem is to realize sustainable and green electronics, using new classes of recyclable and eco-friendly electronic materials and substrates. Innovative polymers, such as vitrimers, are promising candidates, thanks to their recyclability and biodegradability. In this work, vitrimers were synthesized and implemented for the first time as green substrate for transient thin-film temperature sensors using vacuum deposition. Here, Silver- and Zinc-based resistance temperature detectors (RTDs), as well as semiconductive thermistor exhibiting sensitivities of 0.21%°C-1, 0.18%°C-1 and -0.22%°C-1, are reported. All temperature sensors exhibit good linearity and stability over 10 heating-cooling cycles between 25 °C and 70 °C. Finally, to demonstrate the chemical degradability of a Zn RTD, the sensor was dissolved in water, which leads to a loss of functionality after 30 min and its complete dissolution after 1 h. Overall, the combination of recyclable vitrimers and green dissolvable electronics represents an innovative route towards a fully sustainable technological platform.