Stability of fully printed flexible thermistors under static and dynamic thermal stressing

The growing demand for sensors required to fulfil the vision of embedding electronic functionalities into literally every object surrounding us in a daily life could be satisfied by the means of printed electronics. This work is focused on fully screen-printed temperature sensors on PET foil and characterization of their stability under dynamic and static thermal stressing. Two proprietary metal-oxide based thermosensitive formulations were used to prepare printed thermistors, which were either non-encapsulated or protected with a foil lamination. Sensors were subjected to dynamic thermal cycling right after their preparation ((10 - 50) degrees C / 216 h) and then again after the additional thermal annealing (50 degrees C / 72 h). Despite the dissimilar relative resistance change during the first dynamic cycling, after the annealing both thermosensistive formulations exhibited very similar behaviour. The foil lamination turned out to eliminate resistance fluctuations during the static themal stressing and it also maintained lower relative resistance drift during dynamic thermal stressing.