With the rapid development of portable electronic devices, there is an urgent need for the multifunctional composites like excellent electromagnetic interference (EMI) shielding performance, mechanical property, and thermal management capabilities. Here, due to the low thermal conductivity of phase change materials (PCMs), a sandwich structure carbon nanotube/phase change microcapsule/carbon nanotube (CNT/PMC/CNT (CPC)) film was prepared by vacuum‐assisted filtration (VAF) method. CNT, PMC, and cellulose nanocrystal (CNC) were used as functional fillers. The addition of CNCs was used to improve the mechanical performance of CPC film. Compared with PMC‐CNC (PC) film, CPC film with sandwich structure prevented leakage phenomenon efficiently. Subsequently, the use of ultrasonic‐assisted forced infiltration (UAFI) successfully infiltrated polydimethylsiloxane (PDMS) matrix in the filler skeleton to obtain CNT/PMC/CNT/PDMS (CPCP) composites. When filler mass ratio (CNT: CNC and PMC: CNC) reached 10:1, the thermal conductivity of CPCP composites was 2.32 W/(m·K) and total EMI shielding effectiveness (EMI SET) of it with 0.38 mm thickness reached 37.46 dB at 12.4 GHz. Besides, these sandwich composites exhibited the good mechanical properties and heat storage capacity. And we systematically observed the impact of different addition amounts of PC homogeneous dispersing solution on phase change ability of CPCP10:1 composites. In summary, CPCP phase change composites with sandwich structure shows potential application prospect in thermal management materials with EMI shielding of electronic devices.Highlight The sandwich structure CPCP composites prepared by the combination of VAF and UAFI method, showing superior thermal conductivity and phase change ability. CPCP has excellent EMI shielding performance, which can meet the need of TMMs with EMI shielding performance. Compared with same thickness PC film, sandwich CPC film can prevent leakage phenomenon efficiently.

中文翻译：

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高效制备三明治结构聚二甲基硅氧烷基相变复合材料

随着便携式电子设备的快速发展，迫切需要具有优异的电磁干扰（EMI）屏蔽性能、机械性能和热管理能力等多功能复合材料。这里，由于相变材料（PCM）的导热系数较低，采用真空辅助过滤（VAF）方法制备了夹层结构碳纳米管/相变微胶囊/碳纳米管（CNT/PMC/CNT（CPC））薄膜。 CNT、PMC 和纤维素纳米晶体 (CNC) 被用作功能填料。 CNC的添加用于提高CPC薄膜的机械性能。与PMC-CNC（PC）薄膜相比，三明治结构的CPC薄膜可以有效防止泄漏现象。随后，利用超声波辅助强制渗透（UAFI）成功地将聚二甲基硅氧烷（PDMS）基体渗透到填料骨架中，得到CNT/PMC/CNT/PDMS（CPCP）复合材料。当填料质量比（CNT：CNC和PMC：CNC）达到10：1时，CPCP复合材料的热导率为2.32 W/（m·K），总EMI屏蔽效能（EMI东南欧时间）厚度为 0.38 mm 时，在 12.4 GHz 时达到 37.46 dB。此外，这些夹层复合材料表现出良好的机械性能和蓄热能力。系统地观察了PC均质分散液不同添加量对CPCP相变能力的影响10:1复合材料。综上所述，三明治结构CPCP相变复合材料在电子设备EMI屏蔽热管理材料中显示出潜在的应用前景。 结合VAF和UAFI方法制备的夹层结构CPCP复合材料，表现出优异的导热性和相变能力。 CPCP具有优异的EMI屏蔽性能，可以满足TMM对EMI屏蔽性能的需求。 与相同厚度的PC膜相比，夹层CPC膜可以有效防止渗漏现象。