Highly Thermally Conductive Aramid Nanofiber Composite Films with Synchronous Visible/Infrared Camouflages and Information Encryption

Abstract

The highly thermally conductive composites that combine visible light/infrared camouflage and information encryption has been endowed with great significance in facilitating the application of 5G communication technology in military fields. This work uses aramid nanofibers (ANF) as the matrix, hetero‐structured silver nanowires@boron nitride nanosheets (AgNWs@BNNS) prepared by in‐situ growth as fillers, which are combined to fabricate sandwich structured thermally conductive and electrically insulating (BNNS/ANF)‐(AgNWs@BNNS)‐(BNNS/ANF) (denoted as BAB) composite films by “filtration self‐assembly, air spraying, and hot‐pressing” method. When the mass ratio of AgNWs@BNNS to BNNS is 1:1 and the total mass fraction is 50 wt%, BAB composite film has the maximum in‐plane thermal conductivity coefficient (λ∥ of 10.36 W/(m·K)), excellent electrical insulation (breakdown strength and volume resistivity of 41.5 kV/mm and 1.21×1015 Ω·cm, respectively) and mechanical properties (tensile strength of 170.9 MPa). 50 wt% BAB composite film could efficiently reduce the equilibrium temperature of the central processing unit (CPU) working at full power, resulting in 7.0oC lower than that of the CPU solely integrated with ANF directly. In addition, BAB composite film boasts adaptive visible light/infrared dual camouflage properties on cement roads and jungle environments, as well as the function of fast encryption of QR code information within 24 seconds.

Highly and Uniformly Thermal Conductive Phase Change Composites by Constructing the Bidirectionally Oriented and Interconnected Boron Nitride Nanosheet Network

“…This is due to the close packing of numerous BNNSs. Although considerable efforts have been dedicated to designing thermal conductive composites, most of them realized the improvement of TC along with one direction, causing a compromised TC in the perpendicular direction. , In contrast, our OBP offers a feasible solution for implementing a rapid and uniform heat transfer. It is bound up with the construction of effective phonon transportation pathways by the radially and vertically oriented overlapped BNNSs.…”

Preparation of Structural Heat-and-Radiation-Resistant Integrated Epoxy by Constructing a Carborane-Hybridized Cross-Linked Network

“…The heat resistance index (T HRI ) is a commonly used parameter to characterize the heat resistance of a material as well. 36,37 With the increase in the content of carborane, the T HRI of the materials continuously improved (Figure S4 and Table 2). When the carborane content reached 26.40, the material's T HRI reached the maximum values of 165.79 °C (in nitrogen) and 166.95 °C (in air).…”

Sandwich-Structured Thermal Interface Materials with High Thermal Conductivity

“…Traditional heat dissipation methods are no longer sufficient to meet the heat dissipation needs of high-power devices. Therefore, exploring thermal interface materials (TIMs) with high thermal conductivity has become crucial. − Ideal TIM materials require good mechanical properties to match the inherent surface roughness and maintain good contact of heater and heat sink during thermal cycling along with excellent heat transfer performance. − Polymer-based materials are widely used in TIMs due to their excellent mechanical properties and processability. However, their thermal conductivity is low and unstable at high temperatures, which has led to the development of alternative methods to enhance the performance of the high polymer matrix-based TIMs by adding high thermal conductivity materials, such as metal (Al, Ag, and Cu), ceramic (Al 2 O 3 , BN, and SiC , ), and carbon-based fillers (diamond, carbon fiber, − and graphene − …”