“…Heat dissipation has become a growing demand to keep up with the tendency of miniaturization and densification of integrated circuits and electronic devices in the fifth-generation communication era. − The heat accumulation generated in a confined space forms a concentrated hot spot, which closely relates to the service reliability and lifetime of electronic components. − However, the existing thermal management materials, such as electronic packaging materials or equipment components, still suffer from a low thermal conductivity of 1–5 W·m –1 ·K –1 . , In addition, despite the acceptable heat dissipation efficiency of thermal management materials, its poor mechanical properties further limit their practical applications in flexible and collapsible electronic devices. − Therefore, it is of great interest to exploit thermal management materials with high thermal conductivity and excellent mechanical properties. , …”
The high-speed development of miniaturization and densification of electronic devices brings about substantive needs for high thermal conductive and mechanical composites to ensure service reliability and prolong the lifetime of electronic components. Herein, we develop a facile and environmental strategy to fabricate flexible composite films that combine biodegradable bacterial cellulose (BC) and polydopamine (PDA) as well as highly thermally conductive hexagonal boron nitride (h-BN). The well-stacked layered BN 0.5 @PDA/BC and BN 7.0 @PDA/BC composite films exhibit higher thermal and mechanical performance relative to the unmodified BN 0.5 /BC and BN 7.0 /BC composite films, but the optimum properties closely relate to the size of h-BN fillers. The BN 7.0 @PDA/BC film exhibits higher in-plane thermal conductivity of 26.8 W• m −1 •K −1 than that of BN 0.5 @PDA/BC films at the same h-BN loading of 82 wt % because the oriented BN 7.0 @PDA fillers have more probability of forming the effective thermally conductive pathways supported by the Agari model fitting and finite element simulations, whereas the BN 0.5 @ PDA/BC film displays a stronger tensile strength of 18.7 MPa owing to the better match between small-sized BN 0.5 @PDA fillers and BC nanofibers. Meanwhile, the composite films are employed for cooling high-power LED module application, and the BN 7.0 @ PDA/BC film shows higher cooling efficiency than that of commercial polyimide film. Such a concise and low-cost composite film meets the increasing demands for flexible wearable equipment and foldable electronics.
“…Heat dissipation has become a growing demand to keep up with the tendency of miniaturization and densification of integrated circuits and electronic devices in the fifth-generation communication era. − The heat accumulation generated in a confined space forms a concentrated hot spot, which closely relates to the service reliability and lifetime of electronic components. − However, the existing thermal management materials, such as electronic packaging materials or equipment components, still suffer from a low thermal conductivity of 1–5 W·m –1 ·K –1 . , In addition, despite the acceptable heat dissipation efficiency of thermal management materials, its poor mechanical properties further limit their practical applications in flexible and collapsible electronic devices. − Therefore, it is of great interest to exploit thermal management materials with high thermal conductivity and excellent mechanical properties. , …”
The high-speed development of miniaturization and densification of electronic devices brings about substantive needs for high thermal conductive and mechanical composites to ensure service reliability and prolong the lifetime of electronic components. Herein, we develop a facile and environmental strategy to fabricate flexible composite films that combine biodegradable bacterial cellulose (BC) and polydopamine (PDA) as well as highly thermally conductive hexagonal boron nitride (h-BN). The well-stacked layered BN 0.5 @PDA/BC and BN 7.0 @PDA/BC composite films exhibit higher thermal and mechanical performance relative to the unmodified BN 0.5 /BC and BN 7.0 /BC composite films, but the optimum properties closely relate to the size of h-BN fillers. The BN 7.0 @PDA/BC film exhibits higher in-plane thermal conductivity of 26.8 W• m −1 •K −1 than that of BN 0.5 @PDA/BC films at the same h-BN loading of 82 wt % because the oriented BN 7.0 @PDA fillers have more probability of forming the effective thermally conductive pathways supported by the Agari model fitting and finite element simulations, whereas the BN 0.5 @ PDA/BC film displays a stronger tensile strength of 18.7 MPa owing to the better match between small-sized BN 0.5 @PDA fillers and BC nanofibers. Meanwhile, the composite films are employed for cooling high-power LED module application, and the BN 7.0 @ PDA/BC film shows higher cooling efficiency than that of commercial polyimide film. Such a concise and low-cost composite film meets the increasing demands for flexible wearable equipment and foldable electronics.
“…Oppositely, at high filler loadings, the TC increases obviously because the contiguous Ni particles start to touch and form the particle clusters or akin networks, which will not only hinder and inhibit the interfacial thermal resistance, but also create heat conductive paths for phonon’ transmission. 11,25,27,47,52 Take an example, the 60 wt% Ni-0/PVDF demonstrates a TC of 0.83 W/(m·K), compared with 0.20 for pure PVDF.Figure 11.(a) TC of PVDF composites with Ni and Ni@NiO particles at various filler loadings; (b) schematic representation showing the heat conduction mechanism in both Ni/PVDF and Ni@NiO/PVDF composites.…”
An insulating interlayer between conductive particles and polymer is crucial for preparing polymer dielectrics with high dielectric permittivity ( ε) but low loss and high breakdown strength ( E b). To restrain the large loss of raw nickel (Ni)/poly (vinylidene fluoride) (PVDF) composites when still maintaining a high- ε at the percolation threshold ( f c) of conductive fillers, in this work, nanoscale nickel oxide (NiO) shell with diverse thickness was coated around the surface of Ni particles via a facile thermal calcination at 650°C under air, and the gained Ni@NiO particles were composited with PVDF to produce morphology-controllable high- ε, low loss composites. The influences of the NiO shell and thickness on the dielectric performances and thermal conductivity (TC) of the composites were investigated in terms of filler loading and frequency. Compared with raw Ni/PVDF, the Ni@NiO/PVDF composites exhibit remarkably suppressed dielectric loss and enhanced E b and TC because the NiO interlayer not only prevents the Ni particles from direct contact and hinders the long-range electron migration thereby resulting in rather low leakage current, but also simultaneously suppresses thermal interfacial resistance and enhances interfacial compatibility between the fillers and the matrix subsequently resulting in improved TC. Therefore, the Ni@NiO/PVDF with high ε-low loss, heightened E b and TC present appealing potential applications in microelectronics and electrical industries.
“…Herein, to evidently improve the polymer/BNNSs nanocomposite properties, some design mentalities, such as improving the dispersion and orientation of BNNS, promoting the BNNS to selectively distribute at different blending phases interfaces, and designing the bioinspired structures, are adopted by many researchers to date. [ 93–97 ] In this part, the frequently‐used structural designs and preparation methods for polymer/BNNSs nanocomposites in recent years are introduced.…”
Section: Preparation For Bnns‐based Polymer Nanocompositesmentioning
With the rapid development of electronic devices toward the miniaturization, integration, and multi‐functionalization, the device stability, reliability, and service life face significant challenges due to the greatly increased heat accumulation. Therefore, it is highly desired to develop efficient thermal dissipation materials in thermal management. Thermally conductive polymer composites are expected to be widely applied in 5G communication, electronic packaging, and energy storage, owing to the ease of processing, good flexibility, low cost, etc. Boron nitride nanosheet (BNNS) is generally used as highly thermal conductive nanofillers for greatly improving the thermal conductivity of polymer. Mass production of high quality BNNS with desired properties and the structural design principles and fabrication methods for polymer/BNNS nanocomposites are critical to achieve extensive applications. Here, this review summarizes the latest advancement of the preparation method of BNNS and its polymer nanocomposites, as well as the innovatively structural design for observably improving the thermal management capability and energy storage performance of polymer/BNNS nanocomposites, expecting to offer some guidance on how to massively fabricate the BNNS and highly thermally conductive polymer composites.
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