A combination of nanodiamond and boron nitride for the preparation of polyvinyl alcohol composite film with high thermal conductivity

Enhanced In-Plane Thermal Conductivity and Mechanical Strength of Flexible Films by Aligning and Interconnecting Si3N4 Nanowires

As the rapid development of advanced foldable electronic devices, flexible and insulating composite films with ultra-high in-plane thermal conductivity have received increasing attention as thermal management materials. Silicon nitride nanowires (Si₃N₄NWs) have been considered as promising fillers for preparing anisotropic thermally conductive composite films due to their extremely high thermal conductivity, low dielectric properties, and excellent mechanical properties. However, an efficient approach to synthesize Si₃N₄NWs in a large scale still need to be explored. In this work, large quantities of Si₃N₄NWs were successfully prepared using a modified CRN method, presenting the advantages of high aspect ratio, high purity, and easy collection. On the basis, the super-flexible PVA/Si₃N₄NWs composite films were further prepared with the assistance of vacuum filtration method. Due to the highly oriented Si₃N₄NWs interconnected to form a complete phonon transport network in the horizontal direction, the composite films exhibited a high in-plane thermal conductivity of 15.4 W·m^-1·K^-1. The enhancement effect of Si₃N₄NWs on the composite thermal conductivity was further demonstrated by the actual heat transfer process and finite element simulations. More significantly, the Si₃N₄NWs enabled the composite film presenting good thermal stability, high electrical insulation, and excellent mechanical strength, which was beneficial for thermal management applications in modern electronic devices.

Emerging Flexible Thermally Conductive Films: Mechanism, Fabrication, Application

Effective thermal management is quite urgent for electronics owing to their ever-growing integration degree, operation frequency and power density, and the main strategy of thermal management is to remove excess energy from electronics to outside by thermal conductive materials. Compared to the conventional thermal management materials, flexible thermally conductive films with high in-plane thermal conductivity, as emerging candidates, have aroused greater interest in the last decade, which show great potential in thermal management applications of next-generation devices. However, a comprehensive review of flexible thermally conductive films is rarely reported. Thus, we review recent advances of both intrinsic polymer films and polymer-based composite films with ultrahigh in-plane thermal conductivity, with deep understandings of heat transfer mechanism, processing methods to enhance thermal conductivity, optimization strategies to reduce interface thermal resistance and their potential applications. Lastly, challenges and opportunities for the future development of flexible thermally conductive films are also discussed.

Water-soluble polyvinyl alcohol composite films with nanodiamond particles modified with polyethyleneimine

Nanodiamond particles modified with polyethyleneimine were added to polyvinyl alcohol matrices to obtain composites with good thermal and mechanical properties.

Beyond homogeneous dispersion: oriented conductive fillers for high κ nanocomposites

Rational design of structures for regulating the thermal conductivities (κ) of materials is critical to many components and products employed in electrical, electronic, energy, construction, aerospace, and medical applications. As such, considerable efforts have been devoted to developing polymer composites with tailored conducting filler architectures and thermal conduits for highly improved κ. This paper is dedicated to overviewing recent advances in this area to offer perspectives for the next level of future development. The limitations of conventional particulate-filled composites and the issue of percolation are discussed. In view of different directions of heat dissipation in polymer composites for different end applications, various approaches for designing the micro- and macroscopic structures of thermally conductive networks in the polymer matrix are highlighted. Methodological approaches devised to significantly ameliorate thermal conduction are categorized with respect to the pathways of heat dissipation. Future prospects for the development of thermally conductive polymer composites with modulated thermal conduction pathways are highlighted.

Recent Advances in Preparation, Mechanisms, and Applications of Thermally Conductive Polymer Composites: A Review

At present, the rapid accumulation of heat and the heat dissipation of electronic equipment and related components are important reasons that restrict the miniaturization, high integration, and high power of electronic equipment. It seriously affects the performance and life of electronic devices. Hence, improving the thermal conductivity of polymer composites (TCPCs) is the key to solving this problem. Compared with manufacturing intrinsic thermally conductive polymer composites, the method of filling the polymer matrix with thermally conductive fillers can better-enhance the thermal conductivity (λ) of the composites. This review starts from the thermal conduction mechanism and describes the factors affecting the λ of polymer composites, including filler type, filler morphology and distribution, and the functional surface treatment of fillers. Next, we introduce the preparation methods of filled thermally conductive polymer composites with different filler types. In addition, some commonly used thermal-conductivity theoretical models have been introduced to better-analyze the thermophysical properties of polymer composites. We discuss the simulation of λ and the thermal conduction process of polymer composites based on molecular dynamics and finite element analysis methods. Meanwhile, we briefly introduce the application of polymer composites in thermal management. Finally, we outline the challenges and prospects of TCPCs.