ore, the design of the low-dimensional macroscopic form of aerogel still has certain challenges, which restricts the function of aerogel material in confined space thermal management, such as the actual thermal control of the emerging 5G portable/wearable electronic system in the future demand.
In order to realize the thin and light design of aerogel materials, Zhang Xue, a researcher team from Suzhou Institute of Nanotechnology, Chinese Academy of Sciences, and Professor Liao Jianhe's team from Hainan University, found a cutable and compressible aerogel precursor, and then developed a simple The thin and light design method of aerogel. Through the water-tert-butanol co-solvent system, the hydrogen bond assembly of boric acid and melamine is controlled to obtain the melamine-diborate (M·2B) aerogel bulk material formed by entangled and overlapped nanobelts. The aerogel block has the characteristics of being cuttable and compressible, and has good processability. After simple cutting, compression and subsequent high-temperature pyrolysis, a flexible, self-supporting boron nitride aerogel film was successfully obtained, as shown in Figure 1. Through the adjustment of the process parameters, the thickness, density, shape and size of the boron nitride aerogel film can be effectively adjusted, and the obtained boron nitride aerogel film can be bent at room temperature, liquid nitrogen and flame good mechanical flexibility.
In addition, the above-mentioned boron nitride aerogel film is used as a support material to successfully obtain a boron nitride aerogel phase change film. Thanks to the significant capillary force of the aerogel itself, it can effectively restrain and confine the organic solid-liquid phase change material in the molten state, and prevent the leakage of the molten phase change material. The obtained boron nitride aerogel film exhibits good shape stability; the obtained boron nitride aerogel phase change composite film has a high phase change enthalpy and has a thermal conductivity better than that of current commercial flexible phase change materials.
Aerogels and their phase change composite materials have the following thermal management potentials:
1) The aerogel film has the characteristics of low thermal conductivity, lightness and thinness, which can isolate the heat in the confined space;
2) The aerogel phase change composite film can reversibly absorb or release heat in a temperature-changing environment, and maintain its own temperature relatively constant to achieve the limitation and modulation of thermal energy.
The researchers initially explored the feasibility of the boron nitride aerogel film and its phase change composite film in the diversified thermal management of advanced electronic systems (such as portable, wearable, 5G, etc.), and put forward a proposal based on thermal insulation. Two thermal management strategies with thermal energy modulation and their application forms and scenarios. Aerogel film and phase change composite film can effectively change and regulate the direction of heat flow, prevent heat from spreading to nearby biological tissues and other functional units, provide a comfortable operating environment for electronic systems, and provide a comfortable environment for the human body using electronic devices Wear or use environment.