Reliable Temperature-Controlled Switching Between Positive and Negative Thermal Coefficient of Resistance in Continuous Carbon Fiber - Poly(ε-Caprolactone) Composites

We present continuous carbon fiber (CF) tows embedded in a low melting temperature polymer, poly(ε-caprolactone) (PCL), forming a CF-PCL composite. We show that such composites exhibit a stable, controllable, and reversible temperature coefficient of resistance (TCR) from a negative to a positive and back to a negative temperature coefficient of resistance while increasing temperature across the melting point of the PCL. This advances the state of the art by providing a reliable, fatigue-resistant smart composite material for novel applications, such as self-regulating implants or thermal management in biomedical devices.