Potential temperature sensing of oriented carbon-fiber filled composite and its resistance memory effect

Conductive polymer composites have been applied in temperature sensing owing to its resistance response to temperature change. In this work, composites with short carbon fibers (CFs) filled in silicon rubber (SR) were 3D printed. The positive temperature coefficient (PTC) effect of the composite resistance behaved anisotropically due to the CFs’ orientation, where the PTC intensity was lower when tested along the CFs’ orientation than that along other directions. The composites owned an excellent PTC effect reproducibility at the temperature of 25 ~ 100 °C. In-situ observation shows that the CFs in the composites shifted about 2.62 ± 1.05 μm when the temperature increased from 25 °C to 80 °C. The resistance creep under isothermal aging treatment reveals that the composites could keep their resistance relatively stable at the isothermal aging of 20 ~ 80 °C. The mechanical loads could help the crept resistance to recover to its original value very quickly, which was referred to resistance memory effect (RME) in this article. CF/SR composite was finally connected into circuits as thermistor and temperature sensor, which verified a potential application for temperature sensing.