Polymer-based positive temperature coefficient(PTC)composites show exceptional potential for smart thermal management owing to temperature-responsive resistivity.However,conventional PTC composites with high Curie tem...Polymer-based positive temperature coefficient(PTC)composites show exceptional potential for smart thermal management owing to temperature-responsive resistivity.However,conventional PTC composites with high Curie temperatures(T_(c)>50℃)are unsuitable for precision electronics requiring room-temperature operation.The development of low-Tc composites(T_(c)<50℃)faces challenges in balancing electrical resistivity,stability,and sensitivity.We present a ternary composite design where carbon black(CB)is selectively dispersed in myristyl alcohol(MA)phase,stabilized by an ethylene vinyl acetate(EVA)matrix.The reversible solid-liquid transition of MA dynamically modulates CB conductive networks,while the elasticity of EVA suppresses phase migration under elevated thermal conditions.The MA/EVA/CB composite achieves unprecedented performance:low Tc(35℃),ultralow initial resistivity(50Ωcm),high PTC intensity(7.0),and exceptional cycling stability(>95%resistivity retention after 100 thermal cycles),surpassing previous benchmarks.Even after real space-environment exposure for 14 days,it retains ultralow resistivity and high PTC intensity.DSC/FTIR analyses confirm molecular integrity,validating stability under extreme conditions.Microstructural studies reveal that MA phase melting/crystallization governs conductive network disruption/reconfiguration.A self-regulating heater fabricated from this composite stabilizes an aluminum block at near Tc(30.6±0.03℃)at 20 V and−10℃ environments without external controls.The low-Tc PTC composites demonstrate transformative potential in adaptive thermal management for aerospace electronics.展开更多
基金supported by the National Natural Science Foundation of China(U24A2074,52403045)the Natural Science Foundation of Sichuan Province(24NSFSC0160)+1 种基金the Postdoctoral Fellowship Program of CPSF(GZC20241106)the Opening Project of Robotic Satellite Key Laboratory of Sichuan Province。
文摘Polymer-based positive temperature coefficient(PTC)composites show exceptional potential for smart thermal management owing to temperature-responsive resistivity.However,conventional PTC composites with high Curie temperatures(T_(c)>50℃)are unsuitable for precision electronics requiring room-temperature operation.The development of low-Tc composites(T_(c)<50℃)faces challenges in balancing electrical resistivity,stability,and sensitivity.We present a ternary composite design where carbon black(CB)is selectively dispersed in myristyl alcohol(MA)phase,stabilized by an ethylene vinyl acetate(EVA)matrix.The reversible solid-liquid transition of MA dynamically modulates CB conductive networks,while the elasticity of EVA suppresses phase migration under elevated thermal conditions.The MA/EVA/CB composite achieves unprecedented performance:low Tc(35℃),ultralow initial resistivity(50Ωcm),high PTC intensity(7.0),and exceptional cycling stability(>95%resistivity retention after 100 thermal cycles),surpassing previous benchmarks.Even after real space-environment exposure for 14 days,it retains ultralow resistivity and high PTC intensity.DSC/FTIR analyses confirm molecular integrity,validating stability under extreme conditions.Microstructural studies reveal that MA phase melting/crystallization governs conductive network disruption/reconfiguration.A self-regulating heater fabricated from this composite stabilizes an aluminum block at near Tc(30.6±0.03℃)at 20 V and−10℃ environments without external controls.The low-Tc PTC composites demonstrate transformative potential in adaptive thermal management for aerospace electronics.
