1成果简介
　　功率密度的快速提升与紧凑型电子设备空间的日益局限，迫切需要兼具高导热性与绝缘性的散热胶带。然而现有胶带在厚度超过200微米时，其面内导热系数(κ)低于70 W m⁻²·K⁻¹，限制了其在高热流密度设备中的应用。本文，上海交通大学史坤明 助理研究员、黄兴溢 教授等在《ADVANCED FUNCTIONAL MATERIALS》期刊发表名为“Graphene Paper-Based Multilayer Thermally Conductive Tapes with Exceptional Electrical Insulation for High Heat Flux Dissipation”的论文，研究通过将石墨烯纸夹在氮化硼纳米片填充的聚合物纳米复合粘合剂中，并与氮化硼片填充的聚合物复合薄膜串联组合，开发出一种多层高导热绝缘胶带（MTCEIT）。
　　该复合材料在约300微米厚度下展现出121.22 W m⁻¹ K⁻¹的超高热导率，同时保持5.07×10¹¹ Ω·cm的体积电阻率和36.9 kV mm⁻¹的威布尔特性击穿强度。该多层结构赋予MTCEIT卓越的电绝缘性能与高效散热能力：在超薄笔记本中可使中央处理器（CPU）平衡温度降低9℃，并在无强制冷却条件下稳定超薄智能手机的视频帧率（波动≤0.1帧/秒）。本研究为紧凑型电子设备的高热通量散热难题提供了创新解决方案。
　　2图文导读 

　　图1、Design of MTCEITs. a) Schematic of the heat dissipation system of a compact electronic device with MTCEIT. b) Surface temperature distribution of tapes with different structures at steady state in the FE simulations. Maximum equilibrium temperatures of the heat source in FE simulations as functions of c) thickness proportion of each layer, d) κ and κ//⊥ of the adhesive layer, e) thermal contact resistance between the adhesive layer and the ultrahigh-κ layer (R//adh-ultrahigh-κ//), and between the adhesive layer and the backing layer (Radh-backing).

　　图2、Structure and mechanical properties of MTCEITs. a) Optical image of an MTCEIT and a commercial graphene paper. SEM images of b) the cross-sectional surface of the MTCEIT and c) compact layer-layer contact. d) EDS spectra and e) XRD pattern of the MTCEIT. f) Bent and g) shaped MTCEITs. h) Tensile stress–strain curves of MTCEITs.

　　图3、Thermal conduction and electrical insulation of MTCEITs. a) Schematic of κ measurement. The diameter of the bottom hole (Φ), the inner and outer diameters of the discontinued circular ring hole on the cover (Φ//1 and Φ2), and the sample diameter (Φsam) are marked in the diagram. b) κ of MTCEITs with a thickness of ≈300 µm. c) Comparison of κ and thickness of different electrically insulating films. d) R////total between the graphene layer and various substrates. e) Volume resistivity and f) breakdown strength of MTCEITs. g) Optical image and infrared thermal images of a 70BN/SR (410 µm thick, κ = 3.82 W m//−1 K−1, κ⊥ = 1.35 W m−1 K−1), a commercial high-κ composite film (30 µm thick, κ = 50 W m////−1 K−1) with an adhesive layer (108 µm thick, κ⊥ = 0.23 W m−1 K−1), and MTCEIT (285 µm thick, κ = 121.22 W m//−1 K−1, κ⊥ = 1.33 W m−1 K−1) on a heat plate.

　　图4、Heat dissipation of a thin laptop. a) Optical images of the laptop motherboard. The dimension of MTCEIT is 130 mm × 60 mm. b) Schematic diagram of the simplified CPU heat dissipation system. c) Infrared thermal images of the laptop. d) Temperature evolution and e) temperatures at 1200 s of the CPU. The inset in (d) shows an optical image of the laptop under test. All tests were conducted under normal working conditions. Temperatures were measured by the built-in sensor in the CPU and monitored via AIDA64 Extreme software.

　　图5、Heat dissipation of an ultrathin smartphone without forced cooling. a) Schematic diagram of the smartphone. b) Optical image of the smartphone backside with MTCEIT (50 mm × 30 mm). The backside cover was removed for imaging. c) Infrared thermal images of the smartphone. d) SoC temperature evolution. The inset shows an optical image of the smartphone under test. e) Temperature variation of the SoC under stressing cycles. f) Frame rates of the UHD video during playback tests. All tests in (d), (e), and (f) were conducted in a normal working environment. Temperatures in (d) and (e) were measured using the built-in sensor in SoC and read via ANTUTU Benchmark software. Frame rates in (f) were logged by 3Dmark.
　　3小结
　　通过将石墨烯层夹在两层10BNNS/PBCOEA层之间，再叠加70BN/SR层，成功制备出具有卓越电绝缘性能的多层高导热性胶带。该胶带兼具石墨烯层与70BN/SR背衬层的高介电常数，以及10BNNS/PBCOEA粘合层的低热阻特性。由此，该MTCEIT材料在约300微米厚度下实现121.22 W m⁻¹ K⁻¹的介电常数，其介电常数×厚度值达34.6 mW K⁻¹。此外，尽管石墨烯层具有高电导率，但电场完全局限于绝缘的70BN/SR层和10BNNS/PBCOEA层。因此，该多层胶带在100伏直流电压下展现出高达5.07×10¹¹欧姆·厘米的电阻率，并具备36.9千伏·毫米的维布鲁特性击穿强度，满足绝大多数电子设备的绝缘要求。在实际应用中，MTCEIT可显著降低笔记本电脑CPU温度达9.0°C，并将智能手机超高清视频帧率波动控制在0.1帧/秒以内。该多层结构大幅提升了电绝缘胶带的导热能力，为高热流散热提供了可行解决方案。
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