A Novel Positive Temperature Coefficient Composite with Low Curie Temperatures for Thermal Management

Positive temperature coefficient (PTC) materials exhibit significant potential in thermal management due to their adaptive temperature regulation. However, current PTC materials are often constrained in the thermal regulation within the low-temperature range due to the high Curie temperatures. Achieving low Curie temperatures often requires small-molecule polymer matrices, which can compromise mechanical properties and lead to phase change material leakage. To overcome this challenge, this study innovatively proposes a generalized design strategy for bi-continuous phase thermally controlled PTC composite materials (PTCCM) based on polyimide aerogel (PIA) encapsulation. PIA forms a continuous backbone structure, while 1-Tetradecanol serves as a fibrous phase change matrix. Additionally, multi-doped conductive fillers construct an efficient fiber bundle-like network. In the temperature range of 10-50 °C, the PTC strength achieves 3.55, with a low resistivity of 1.5 Ω m. Thanks to its stable PIA skeleton and perfect conductive network, PTCCM can accurately stabilize the device temperature at 29.5 ± 1.5 °C under different low-temperature environments and voltages. The temperature control accuracy is as high as 0.03 °C, presenting excellent cycling stability. These characteristics make it promising in meeting stringent thermal management demands.