1成果简介

 　　有机热电材料在火灾潜伏期远程温度监测及早期火灾预警方面展现出显著的应用潜力。然而其较低的热电效率削弱了传感信号的灵敏度、可靠性和准确性。本文，东莞理工学院谢华理 特聘副教授、吴文剑 特聘教授等在《Progress in Organic Coatings》期刊发表名为“Construction of multiple heterointerfaces in layered thermoelectric nanocoating to realize highly sensitive remote fire-warning”的论文，研究通过合成异质热电纳米线（HTN）与热电石墨烯（TEG），并将其协同组装构建出具有多异质结构与有序层状结构的热电纳米涂层。
　　得益于两种结构的协同效应，该纳米涂层展现出卓越的热电响应温度传感灵敏度、准确度和稳定性。接触火焰后，纳米涂层能在1.3秒内迅速触发火灾预警，即使发生二次燃烧，预警触发时间也仅延长至1.5秒。该纳米涂层在50-300℃温度范围内输出电压呈现精确可重复的线性函数关系（U = 0.0248 T-0.779），集成无线信号发射器后可实现远程实时温度监测。此外，有序层状结构赋予纳米涂层卓越的阻燃性能，使其在阻燃测试中能实现自熄灭。由此，该热电纳米涂层为柔性电子材料的智能防火安全保护开辟了全新路径。
　　2图文导读

　　图1. Preparation routes of (a) HTN, (b) TEG nanosheets and (c) HTN/TEG/CCS nanocoating.

　　图2. SEM images of the cross-sections of (a) HTN/TEG/CCS-1, (b) HTN/TEG/CCS-2, (c, f) HTN/TEG/CCS-3, (d) HTN/TEG/CCS-4 and (e) HTN/TEG/CCS-5; element distribution of the cross section shown in Fig. 2b: (g) C, (h) N and (i) S; (j) digital photos of PET-HTN/TEG/CCS-3. The results indicated that multiple heterostructure and ordered layered structure were formed and endowed the nanocoating with outstanding flexibility.

　　图3. Output voltage curves of HTN/TEG/CCS nanocoatings when being (a) burned and (c) heated at 200 °C; (b) Seebeck coefficient of HTN/TEG/CCS nanocoatings before and after burning; Video snapshots of the fire-warning test of HTN/TEG/CCS-3 nanocoating when being (d) burned and (e) heated at 200 °C. The results demonstrated that the nanocoating exhibited sensitive thermoelectric response, enabling effective temperature-sensing and fire-warning.

　　图4. Thermoelectric response of HTN/TEG/CCS-3: (a,b) Output voltage curves at different temperatures; (c) The fitting relationship line between the maximum output voltage and the treatment temperature; (d) Output voltage curve during 100 cycles of alternating heating (200 °C) and cooling; (e) Output voltage curves and (f) electrical resistance curves for the first and second burning. The results demonstrated that the nanocoating exhibited accurate temperature detection with excellent stability and repeatability.

　　图5. (a) Schematic diagram and (b) video snapshots of remote real-time temperature monitoring and early fire-warning of HTN/TEG/CCS-3 nanocoating.

　　图6. Vertical burning test process of (a) PET and (b) PET-HTN/TEG/CCS-3; (c) HRR and (d) THR curves of PU and PU-HTN/TEG/CCS.

　　图7. (a) XPS spectra of HTN/TEG/CCS-3 nanocoating before and after burning; (b) XPS C1s spectra of HTN/TEG/CCS-3 nanocoating before burning; XPS C1s spectra of the (c) outside and (d) inside of HTN/TEG/CCS-3 nanocoating after burning. The results indicated that high temperature induced the generation of additional conjugated double bonds and aromatic architectures within the HTN/TEG/CCS nanocoating.

　　图8、 Fire-warning and flame-retardant mechanism.
　　3小结
　　通过异质热电纳米线（HTN）与热电石墨烯（TEG）的协同组装，构建出具有多层异质结构与有序层状结构的柔性热电纳米涂层。依托两种结构对热电效应的协同增强作用，该纳米涂层展现出精准、稳定且可重复的温度检测能力，以及高灵敏度的火灾预警功能。在50-300℃温度范围内，纳米涂层输出电压与温度呈线性函数关系，符合U=0.0248T⁻⁰.⁷⁷⁹的方程。值得注意的是，该函数关系在经历100次加热（200℃）与冷却（室温）循环后仍保持稳定。基于此特性，纳米涂层与无线信号发射器集成，实现了远程实时温度监测功能。当暴露于火焰时，纳米涂层能在1.3秒内快速触发火灾警报。即使发生二次燃烧，警报触发时间也仅延长至1.5秒。此外，有序层状结构赋予涂层卓越的阻燃性能，使聚合物基体在阻燃测试中实现自熄灭。由此，该热电纳米涂层为柔性电工材料的智能防火安全防护提供了全新解决方案。
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