02
Taoqing Huang, Tian Wang, Min Chen, et al. Design of Silicon Rubber/BN Film with High Through-plane Thermal Conductivity and Ultra-low Contact Resistance[J]. Chemical Engineering Journal.
链接：doi.org/10.1016/j.cej.2023.143874
总结：该文提出通过结合一种新型的非溶剂诱导相分离工艺“原位焊接”策略，结果表明，室温硫化硅橡胶(RTV SR)注入后，得到的RTV SR/W-BN复合膜在BN负载仅为15 wt%的情况下，通过面导热系数显著提高至15.4 W/(mK)。更重要的是，硅橡胶基体优异的可压缩性和柔韧性，保证了充分的变形，充分填补空隙，从而减少了热源与TIM之间的接触热阻。
Abstract: Polymer-hexagonal boron nitride (BN) composite has become an ideal thermal interface material (TIM) for electronic devices because of its high thermal conductivity and superior electronic insulation. However, owing to the 2D shape and chemical inertness of BN filler, the vertical alignment of BN and the huge thermal resistance are current challenges, which hinder the efficient heat transfer of polymer/BN composites. Herein, by a novel non-solvent induced phase separation process combined “in-situ welding” strategy, we present the fabrication of silicone rubber film with finger-like continuous BN-welded filler skeleton, which reveals a high through-plane thermal conductivity of 15.4 W/(mK) at only ∼ 15 wt% BN. Finite element simulation and nonlinear model analyses theoretically confirm that the filler-to-filler interfacial thermal resistance (ITR) is halved after in-situ welding process. In addition, thanks to the excellent compressibility and conformability of silicon rubber matrix, the contact thermal resistance of this composite film is much lower than that of the commercial thermal pad under different pressure. The proposed strategy opens up a novel and high-throughput preparation strategy for the high-performance TIM for modern electronic devices.
03
Liu Yang, Jiachen Guo, Ling Zhang, et al. Superior thermally conductive, mechanically strong and eletrically insulating nacre-mimetic chitosan/boron nitride nanosheet composite via evaporation-induced self-assembly method[J]. Polymer.
链接：doi.org/10.1016/j.cej.2023.143874
总结：该文通过绿色、简单的蒸发诱导组装技术，可以大规模制备具有优异导热系数、高绝缘性和坚固力学性能的纳米级CS/BNNS薄膜。实验结果表明，CS/BNNS薄膜在70 wt%时的拉伸强度高达104.5 MPa, 导热系数为26.3 W/(m·K)。
Abstract: The development of electronic devices and the strict application environment put forward more requirements on the heat dissipation materials. However, it is still a challenge for thermal management materials to simultaneously possess high thermal conductivity, strong mechanical property and excellent electrical insulation. Herein, inspired by the special structure and function of natural nacre, we report on a large-scale and high-performance nacre-mimetic composite with boron nitride nanosheet (BNNS) as the “brick” and chitosan as the “mortar” via a green, simple evaporation-induced assembly technique. The nacre-mimetic composite film presents high TC of 26.3 W/(m·K) and superior electrically insulating due to well-aligned BNNS and strong interface interaction. In addition, even at BNNS contents as high as 70 wt%, the composite films still possess a tensile strength of 104.5 MPa and a Young's modulus of 8.7 GPa. The composite film used as a thermal interface material for cooling LED chip demonstrates higher heat dissipation efficiency than commercial silicone pad. This approach of constructing nacre-mimetic composite film with an oriented structure offers potential applications for heat dissipation in new portable electronic equipment.
04
Rui Chen, Xue Li, Jierun Ma，et al. Covalently modified graphene and 3D thermally conductive network for PEEK composites with electromagnetic shielding performance[J]. Composite Part A: Applied Science and Manufacturing.
链接：doi.org/10.1016/j.compositesa.2023.107633
总结：通过静电纺丝法制备了NH2-GnPs&MWCNTs/聚醚醚酮(PEBEKt)和冷冻干燥的MWCNTs/PEEK@PBZ复合材料，最佳的面内和面外导热系数值分别为21.0和6.9 W/(mK)，是纯PEEK的90倍和29倍。
Abstract: Polyetheretherketone (PEEK) has inferior interfacial compatibility due to its rigid structure.Hence, achieving the desired thermal conductivity (T) of PEEK composites is challenging.Covalently bonded amino-graphene (NH2-GnPs) and polybenzoxazine (PBZ) can reduce interfacial thermal resistance (ITR). Hybrid NH2-GnPs and multi-walled carbon nanotubes (MWCNTs) were applied synergistically to refine the T pathways. Additionally, the 3D thermally conductive network was constructed from electrospun NH2-GnPs&MWCNTs/ketimine-biphenyl polyetheretherketone (PEBEKt) and freeze-dried MWCNTs/PEEK@PBZ composites arranged in a sandwich structure. The oriented fillers could improve the heat diffusion network by increasing heat flow conveyance. The optimal in-plane and through-plane TC values were 21.0 and 6.9 W/(m·K), respectively, 90 and 29 times those of pure PEEK. The composites also exhibited excellent electromagnetic shielding (80.4dB, 21.1%), thermal stability, and thermal management capabilities. Consequently, the 3D thermally conductive composites can provide a viable idea for thermal management and electromagnetic shielding materials.
05
Yanru Chen, Kai Pang,Xiaoting Liu，et al. Environment-adaptive, anti-fatigue thermal interface graphene foam[J]. Carbon.
链接：doi.org/10.1016/j.carbon.2023.118142
总结：该文采用水塑性泡沫(HPF)和界面强化方法制备了碳基石墨烯泡沫材料(GFR)作为柔性TIM，GFR-TIM不仅具有很高的结构稳定性，而且具有比大多数商用TIMs (5-10 W/mK)更高的导热系数(~17.42 W/mK)。
Abstract: The rapid development of high-power and high-frequency devices in electronics leads to the urgent demands for advanced thermal interface materials (TIMs) with both superior thermal conductivity and excellent structural stability. Many attempts have exploited the silicone-based TIMs with higher thermal conductive fillers, however, their structural stability remains challenging in some extreme conditions. Here we fabricate the carbon-based graphene foam roll (GFR) as flexible TIM by hydroplastic foaming (HPF) and interface strengthening methods. The enhanced interface bonding within GFR by impregnation of graphene oxide (GO) enables its superior structural integrity. It can keep mechanical stability after 10,000 cycles at a compressive strain of 60% and sustain high temperature up to 500 °C, which has never been realized in previous reports. We demonstrate the GFR-TIM not only achieves very high structural stability but also exhibits higher thermal conductivity (∼17.42 W/mK) than most commercial TIMs (5–10 W/mK). The GFR-TIM can serve as an efficient heat-dissipation component for the CPU and shows superior cooling efficiency compared to commercial TIMs. Our work provides an advanced graphene-based TIM with excellent environment-adaptive and anti-fatigue properties, broadening their application in extreme environments, such as hypersonic vehicles, high-throughput satellites and high-power radar systems.
06
Yu Zhao, Zhengguo Zhang, Chuyue Cai, et al. Environment-adaptive, anti-fatigue thermal interface graphene foam[J]. Applied Thermal Engineering.
链接：doi.org/10.1016/j.applthermaleng.2023.120807
总结：该文使用垂直排列的短切碳纤维(VASCFs)用于开发具有高导热性的相变热界面材料PCTIMs，VASCFs/PA/SR材料的导热系数高达7.00 W/(m·K)，远高于之前报道的PCTIMs。
Abstract: Phase change thermal interface materials (PCTIMs) are receiving increasing attention but suffer from low thermal conductivity and are challenging to improve significantly. Here, vertically aligned short-cut carbon fibers (VASCFs) were employed for the first time to develop PCTIMs with high thermal conductivity. The most effective thermal conductivity enhancement was achieved by VASCFs, which were attributed to providing complete heat transfer paths, further verified by the finite element simulation. VASCFs were thus incorporated into an optimized mixture of silicon rubber (SR) and paraffin (PA) to fabricate form-stable phase change thermal pads. The VASCFs/PA/SR thermal pads achieved a thermal conductivity of as high as 7.00 W/(m·K), much higher than that of the previously reported PCTIMs. More significantly, it is revealed that the reduction in thermal impedance induced by the phase change of PA, led to the better heat dissipation performance of VASCFs/PA/SR, thus making the VASCFs/PA/SR phase change thermal pads show potential in practical applications.
07
Guorui Zhang, Sen Xue, Feng Chen, et al. Environment-adaptive, anti-fatigue thermal interface graphene foam[J]. Composites Science and Technology.
链接：doi.org/10.1016/j.compscitech.2022.109784
总结：该文采用熔融挤出法制备了取向度高的短碳纤维（CF）/烯烃嵌段共聚物（OBC）复合材料。所制备的材料在15 vol% CF含量下显示出高达15.06 W/m K的通平面热导率，是平行结构的约10倍。垂直和随机的工作温差达到35.2°C。
Abstract: The rapid development of integrated circuits and electronic devices with increased power density and heat flux, requires effective heat dissipation for thermal management. Constructing a directional thermal pathway from the vertically aligned thermal conductive fillers in the thickness-direction of polymer-based thermal interface materials (TIMs) is a desirable strategy to form materials with high thermal conductivity. However, due to the complexity of vertical orientation technology, fillers with the poor orientation degree weaken the enhancement of through-plane thermal conductivity. In this work, we prepared short carbon fiber (CF)/olefin block copolymer (OBC) composites with high orientation degree via the melting extrusion method on a basis of sharing force induce alignment. Attributed to the high orientation degree of CF in the vertical direction, the as-prepared material shows a through-plane thermal conductivity (κ) up to 15.06 W/m K at a 30 vol% CF content, which is ∼10 times that of a parallel structure. The operating temperature difference between vertical and random reached 35.2 °C, surpassing the characters in most works of literature. This study provides an effective way to develop high-oriented degree and electrical insulation polymer composites with superior κ for scalable thermal management applications in electronic devices.
08
Baokang Yu, Yuhang Zhou, Zhouai Luo, et al.
Highly thermally conductive flexible insulated PI/BNNS@rGO nanocomposite paper with a three-dimensional network bridge structure[J].
Applied Surface Science.
链接：doi.org/10.1016/j.apsusc.2023.157457
总结：该文提出了一种简单的电纺丝-电喷涂技术，用于制备具有双组分纳米片填充纳米纤维三维桥接结构的高导热绝缘纳米复合膜。rGO作为连接相邻堆叠的BNNS层的桥梁，PI/50BNNS@2.5rGO纳米复合纸的面内导热系数达到16.92 W/m⋅K。
Abstract: The sharp increases in power consumption and heating capacity caused by the emergence of intelligent electronic devices necessitate the development of highly thermally conductive thermal interface materials (TIMs) with good heat dissipation properties. Boron nitride nanosheets (BNNS) are ideal materials with high thermal conductivity. Hence, it should be possible to produce flexible high thermal conductivity nanocomposites with a three-dimensional network containing ultrathin, large, and uniformly thick BNNS. In this study, large-scale (1–1.5 µm) fewer-layered (2 nm) BNNS with a high yield of 80% were prepared through the separation of a NaOH–LiCl aqueous solution by a hydrothermal method and in ball milling. Highly thermally conductive insulating nanocomposite paper with a three-dimensional bridging structure of two-component nanosheets filled with nanofibers was fabricated by a simple electrospinning–electrospraying technique. The mechanical properties of the polyimide (PI)/BNNS@reduced graphene oxide nancomposite paper were improved by 168% as compared with those of the PI/BNNS composite. With an increase in the BNNS content, a layered microstructure similar to that of natural nacre was produced, which resulted in a large in-plane thermal conductivity of 16.92 W/m·K. The described method can facilitate the design of TIMs with good electrical insulation properties, thermal stability, and flexibility.
09
Zhouqiao Wei, Ping Gong, Xiangdong Kong, et al.
Enhanced Thermal Conductivity of Nanodiamond Nanosheets/Polymer Nanofiber Composite Films by Uniaxial and Coaxial Electrospinning: Implications for Thermal Management of Nanodevices[J].
ACS Applied Nano Materials.
链接：doi.org/10.1021/acsanm.3c00591
总结：该文提出采用单轴静电纺丝和同轴静电纺丝的方法，制备了不同微观形貌的单轴聚乙烯醇/纳米金刚石片(U-PVA/ND)和同轴聚乙烯醇/纳米金刚石片(C-PVA/ND)复合纤维薄膜。结果表明，ND含量为60 wt %的U-PVA/ND和C-PVA/ND复合纤维的导热系数分别为71.3和85.3 W/(mK)，分别是纯PVA纤维膜的171.2和205.1倍。
Abstract: Nanotechnology is gradually applied to the preparation of heat dissipation materials with the miniaturization of electronic devices. Electrospinning technology has received extensive attention due to its unique advantages in constructing continuous nanofibers. In this work, uniaxial-polyvinyl alcohol/nanodiamond (U-PVA/ND) and coaxial-polyvinyl alcohol/nanodiamond (C-PVA/ND) composite fiber films with different microscopic morphologies were constructed by uniaxial and coaxial electrospinning. The results show that the thermal conductivities of U-PVA/ND and C-PVA/ND composite fibers with 60 wt % ND content are 71.3 and 85.3 W/m·K, respectively, which are 171.2 and 205.1 times greater than that of the pure PVA fiber film. In addition, the maximum thermal decomposition temperature (Tmax) and volume resistivity of the C-PVA/ND composite fiber film were 364.3 °C and 2.29 × 1015 Ω·cm, respectively, demonstrating the excellent thermal stability and electrical insulation of the composite fiber film. This experiment results provide strong evidences of electrospinning technology for the preparation of highly thermally conductive composites. So, thermally conductive films can be used as the outer layer of electronic components to accelerate their heat dissipation and extend their service life.
10
Taoqing Huang, Tian Wang, Jun Jin, et al.
Design of Silicon Rubber/BN Film with High Through-plane Thermal Conductivity and Ultra-low Contact Resistance[J].
Chemical Engineering Journal.
链接：doi.org/10.1016/j.cej.2023.143874
总结：该文采用一种新颖的非溶剂诱导相分离工艺结合“原位焊接”策略，制备了硅橡胶薄膜，该薄膜在~ 15 wt% BN下的通平面导热系数高达15.4 W/(mK)。有限元模拟和非线性模型分析从理论上证实了原位焊接后填料-填料界面热阻(ITR)降低了一半。该策略为现代电子器件的高性能TIM开辟了一种新颖的制备策略。
Abstract: Thermal interface materials (TIMs) with excellent heat dissipation capacity are highly desired for the develop ment of miniaturized, integrated, and dense electronic devices. In addition, with the increasing accumulation of e-waste, the recyclability of TIMs has also become an urgent concern. Herein, a fully recyclable TIM with high thermal conductivity and conformability to the rough surface was prepared based on the synthesized epoxy vitrimer and boron nitride (BN) nanosheet. Results revealed that only by simple hot-pressing, the filled BN could be easily oriented in the plane and led to a thermal conductivity of 3.85 W/m·Kwith the BN content of 40 wt%, which was 30 times higher than that of the pristine epoxy resin and 4.3 times higher than the composite before hot-pressing treatment. The electronic device made of the prepared composite exhibited a 20℃ lower core temperature than the commercial silicone material, due to the superior thermal conduction and mechanical compliance. Moreover, benefiting from the multistage degradation mechanism of the synthesized epoxy vitrimer, the fabricated composite could be efficiently chemically recovered under mild conditions, demonstrating the BN recovery rate of 96.2% and other organic raw materials recovery rate of 73.6% to 82.4%. This work provides us with a new strategy for the design of recyclable and high-performance TIMs.
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