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.
鏈接：doi.org/10.1016/j.cej.2023.143874
總結(jié)：該文提出通過結(jié)合一種新型的非溶劑誘導(dǎo)相分離工藝“原位焊接”策略，結(jié)果表明，室溫硫化硅橡膠(RTV SR)注入后，得到的RTV SR/W-BN復(fù)合膜在BN負(fù)載僅為15 wt%的情況下，通過面導(dǎo)熱系數(shù)顯著提高至15.4 W/(mK)。更重要的是，硅橡膠基體優(yōu)異的可壓縮性和柔韌性，保證了充分的變形，充分填補(bǔ)空隙，從而減少了熱源與TIM之間的接觸熱阻。
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.
鏈接：doi.org/10.1016/j.cej.2023.143874
總結(jié)：該文通過綠色、簡單的蒸發(fā)誘導(dǎo)組裝技術(shù)，可以大規(guī)模制備具有優(yōu)異導(dǎo)熱系數(shù)、高絕緣性和堅(jiān)固力學(xué)性能的納米級(jí)CS/BNNS薄膜。實(shí)驗(yàn)結(jié)果表明，CS/BNNS薄膜在70 wt%時(shí)的拉伸強(qiáng)度高達(dá)104.5 MPa, 導(dǎo)熱系數(shù)為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.
鏈接：doi.org/10.1016/j.compositesa.2023.107633
總結(jié)：通過靜電紡絲法制備了NH2-GnPs&MWCNTs/聚醚醚酮(PEBEKt)和冷凍干燥的MWCNTs/PEEK@PBZ復(fù)合材料，最佳的面內(nèi)和面外導(dǎo)熱系數(shù)值分別為21.0和6.9 W/(mK)，是純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.
鏈接：doi.org/10.1016/j.carbon.2023.118142
總結(jié)：該文采用水塑性泡沫(HPF)和界面強(qiáng)化方法制備了碳基石墨烯泡沫材料(GFR)作為柔性TIM，GFR-TIM不僅具有很高的結(jié)構(gòu)穩(wěn)定性，而且具有比大多數(shù)商用TIMs (5-10 W/mK)更高的導(dǎo)熱系數(shù)(~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.
鏈接：doi.org/10.1016/j.applthermaleng.2023.120807
總結(jié)：該文使用垂直排列的短切碳纖維(VASCFs)用于開發(fā)具有高導(dǎo)熱性的相變熱界面材料PCTIMs，VASCFs/PA/SR材料的導(dǎo)熱系數(shù)高達(dá)7.00 W/(m·K)，遠(yuǎn)高于之前報(bào)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.
鏈接：doi.org/10.1016/j.compscitech.2022.109784
總結(jié)：該文采用熔融擠出法制備了取向度高的短碳纖維（CF）/烯烴嵌段共聚物（OBC）復(fù)合材料。所制備的材料在15 vol% CF含量下顯示出高達(dá)15.06 W/m K的通平面熱導(dǎo)率，是平行結(jié)構(gòu)的約10倍。垂直和隨機(jī)的工作溫差達(dá)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.
鏈接：doi.org/10.1016/j.apsusc.2023.157457
總結(jié)：該文提出了一種簡單的電紡絲-電噴涂技術(shù)，用于制備具有雙組分納米片填充納米纖維三維橋接結(jié)構(gòu)的高導(dǎo)熱絕緣納米復(fù)合膜。rGO作為連接相鄰堆疊的BNNS層的橋梁，PI/50BNNS@2.5rGO納米復(fù)合紙的面內(nèi)導(dǎo)熱系數(shù)達(dá)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.
鏈接：doi.org/10.1021/acsanm.3c00591
總結(jié)：該文提出采用單軸靜電紡絲和同軸靜電紡絲的方法，制備了不同微觀形貌的單軸聚乙烯醇/納米金剛石片(U-PVA/ND)和同軸聚乙烯醇/納米金剛石片(C-PVA/ND)復(fù)合纖維薄膜。結(jié)果表明，ND含量為60 wt %的U-PVA/ND和C-PVA/ND復(fù)合纖維的導(dǎo)熱系數(shù)分別為71.3和85.3 W/(mK)，分別是純PVA纖維膜的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.
鏈接：doi.org/10.1016/j.cej.2023.143874
總結(jié)：該文采用一種新穎的非溶劑誘導(dǎo)相分離工藝結(jié)合“原位焊接”策略，制備了硅橡膠薄膜，該薄膜在~ 15 wt% BN下的通平面導(dǎo)熱系數(shù)高達(dá)15.4 W/(mK)。有限元模擬和非線性模型分析從理論上證實(shí)了原位焊接后填料-填料界面熱阻(ITR)降低了一半。該策略為現(xiàn)代電子器件的高性能TIM開辟了一種新穎的制備策略。
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.
