Polymer composites with a high electrical conductivity (σ) to thermal conductivity (k) ratio have been intensively investigated in recent years. While highly conductive materials, such as metallic fillers or conducting polymers, were used to enhance σ, microstructural engineering was used to decrease k by forming porous structures, such as aerogels or 3D networks. These structures, however, were mechanically vulnerable and could only have limited applications. In this study, multiwalled carbon nanotube /silicone composites with a high σ/k ratio were developed by forming a double-segregated multiwalled carbon nanotube network in the porous body of the composites. The unique microstructure of the composites was created by a novel fabrication process: layer-by-layer deposition with in-situ polymerization of silicone emulsion particles dispersed in a water solvent. This novel process yielded very thick films, >200 µm, with high σ/k values, ∼2 × 104 (S/m)/(W/m·K). These high σ/k composites can be used for various applications, such as resistive heating elements, thermoelectric materials, and wearable thermotherapy.

中文翻译：

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双隔离多壁碳纳米管/有机硅复合材料通过原位有机硅乳液聚合具有大的电热导率比

近年来，人们对具有高电导率 (σ) 与热导率 (k) 比的聚合物复合材料进行了深入研究。虽然使用高导电材料（如金属填料或导电聚合物）来增强 σ，但微结构工程用于通过形成多孔结构（如气凝胶或 3D 网络）来降低 k。然而，这些结构在机械上很脆弱，只能有有限的应用。在这项研究中，通过在复合材料的多孔体中形成双隔离的多壁碳纳米管网络，开发了具有高 σ/k 比的多壁碳纳米管/硅胶复合材料。复合材料的独特微观结构是通过一种新颖的制造工艺创造的：通过分散在水溶剂中的有机硅乳液颗粒的原位聚合进行逐层沉积。这种新工艺产生了非常厚的薄膜，>200 µm，具有高 σ/k 值，∼2 × 104 (S/m)/(W/m·K)。这些高 σ/k 复合材料可用于各种应用，例如电阻加热元件、热电材料和可穿戴热疗。