快速热相变响应的石墨烯复合薄膜及其高效储热放热行为

The thermal fluctuation phenomenon in microelectronic components often leads to the serious electrical failure of the entire device. Controlling the temperature within a narrow range is a major challenge for electronics engineering because of lacking of good thermal conductive materials, and this hinders the development of higher output power and reliable electronic devices. Because the novel graphene-based materials show ultrafast thermal response and high efficient thermal transmission capability, we proposed herein a new design of graphene nanocomposite films (GNFs) for resolving the electronics' thermal fluctuation problems and improving the device's reliability. In the current project, we will prepare new type of GNFs with both ultrahigh thermal conductivity and high efficient heat energy storage and release capability by imbedding various phase change materials (PCMs) among the three-dimensional (3D) graphene network, in which graphene as the fast transport channel of charge carriers for high thermal conductivity. (1) The combination of graphene surface modification technology and 3D self-assembly principle, choosing different phase transformation temperature range of organic phase change materials, self-assembly 3D interconnected graphene networks nanocomposite films with high thermal conductivity and reversible storage/release heat phase transformation will be synthesized for conquering the low thermal conductivity of the PCMs. (2) In the interface confinement condition, exploring relationships between thermal conductivity, thermal expansivity and phase transformation temperature, further studying the enhancement mechanisms in PCMs's heat capacity and heat transmission rate under the condition of the graphene networks interface interaction. (3) According to the different work environment temperature in electronic device, a series of high thermal conductivity of GNFs with the capability of the phase change of temperature range adjustment and storage/release heat energy will be synthesized. The results of this proposed research not only have scientific significance in the fundamental theories of designing advanced functional materials but also have potentials in practical applications for microelectronic components.

电子元件热涨落严重影响高集成微电子系统的使用寿命及运行可靠性。发展兼具高效储热放热功能与快速热响应的石墨烯复合薄膜对解决微电子器件运行热稳定问题具有重要科学应用价值。本项目拟利用高热导石墨烯三维网络骨架结构提供的快速热量传输通道，与贮热相变材料的功能复合有望获得具有快速热相变响应的石墨烯复合薄膜。（1）针对有机相变材料自身热导率低的缺点，发展石墨烯表面修饰方法和三维自组装原理，设计三维网状骨架石墨烯和有机相变材料定型相变复合体系，制备快速导热、储热放热复合薄膜。（2）探索界面限域条件下相变材料热导率、膨胀系数、相变温度等热行为规律，进一步研究石墨烯骨架对相变材料比热容、热传递的影响机制。（3）针对不同工作环境的温控区间，发展一系列高导热-储热-放热石墨烯复合薄膜，实现相变温度区间的调节及其热量快速储存与可控释放。预期成果将为发展新型热界面材料提供新方法，为微电子元器件控热提供关键材料。

电子元件在使用过程中发热问题严重影响高集成微电子系统的使用寿命及运行可靠性。同时合理并高效利用热能，是解决热能供给问题及能源利用率低的有效途径。低品位热能的快速传导、收集、储存、释放、利用技术，一直是节能与热能利用的关键技术，同时也是各国能源研究机构感兴趣的重要研究课题。本项目将纳米技术和自组装技术结合起来，发展了石墨烯表面修饰新方法和三维自组装原理，设计合成了三维网状骨架石墨烯和有机相变材料定型相变复合薄膜材料，实现了低品位热能快速导热、储热放热的热学性能，构筑了热电转换器件，发展了集成传递、存储、释放与热电转换为一体的纳米热控技术；提出并验证了表面限域效应对有机相变材料储热容量、相变温度和相变相应速率等热行为规律的影响机制；通过对石墨烯二维结构与三维骨架的分别构筑实现了对有机相变材料相变温度和响应速率的控制；通过对有机相变材料界面耦合调控，实现了对硬脂酸等相变材料的储热容量的大幅提高。上述研究工作取得了多项具有创新性和系统性的研究成果，在高影响力的国际期刊J. Mater.Chem.，Nanoscale，J. Phys. Chem. C等上发表SCI论文7篇。此外，获得授权专利1项，申请国家发明专利2项。本项目的完成为发展利用纳米技术构筑控热材料和器件，实现在热能控制、节能领域和热电转换等方面的应用提供了理论基础和技术上的可能。