Highly Efficient Adaptive PTC Heaters Enabled by the Combination of Phase-Change Components and Conductive Networks for Room-Temperature Thermal Management

Positive temperature coefficient (PTC) heaters are widely used in self-regulating heating applications. However, it remains challenging to develop PTC heaters that can operate efficiently at low temperatures (<50 °C). Herein, we demonstrate the design of low-transition-temperature (39.5 °C) adaptive PTC composites by the combination of thermally responsive polyethylene glycol (PEG) and conductive carbon black (CB) in a thermoplastic polyurethane (TPU) matrix. The reversible melting and crystallization of the PEG component enable dynamic reconstruction of the conductive network. The results demonstrate that the CB@PEG/TPU composite exhibits an exceptionally high PTC intensity of up to 2.7 at a low transition temperature (39.5 °C) while maintaining a low resistivity of 0.4 Ω·m. The resultant CB@PEG/TPU heater exhibits excellent temperature stability with a temperature fluctuation of 2.1 °C under the environmental conditions of −10 to 10 °C. The outstanding comprehensive performance indicates that the CB@PEG/TPU composite holds broad application prospects in the field of self-regulating heating.