3D-printed shapeable hybrid Nanocellulose/aramid nanofiber aerogels for thermal insulation of portable electronics

The rapid development of telecommunication systems and portable electronics requires the miniaturization and integration of electronic components and devices. However, these advanced compact packings require efficient thermal management, making lightweight, shapeable, and sustainable insulating materials highly desirable. Cellulose aerogels are emerging biogenic porous materials with numerous fascinating characteristics, such as ultralow densities, low thermal conductivities, and design tunability. However, their insufficient heat resistance, mechanical durability, and processability still present significant challenges. Here, 3D-printed hybrid cellulose nanofiber (CNF) aerogels with tailored complex architectures were fabricated. The enhanced mechanical strength and thermal stability of the CNF aerogel were achieved by the introduction of aramid nanofibers (ANF) as reinforcement. The results revealed that an ANF loading of 50 % significantly increased the Young's modulus of the hybrid aerogels (from 16.7 to 176.3 kPa). More importantly, the aerogels exhibited a very low thermal conductivity (0.032 W/(m·K)), which was among the lowest (based on the material density) reported for aerogels. Aerogels prepared via 3D printing demonstrate broad applicability and overcome the inefficiencies and low precision of conventional mold-based fabrication techniques. Moreover, aerogels exhibit excellent recyclability, as they can be repeatedly reformed through a disperse-drying cycles . The advanced performance of 3D-printed aerogels as custom heat insulators was demonstrated by managing hot spot area on a 5G smartphone mainboard. Thus, a sustainable approach for the rapid prototyping of high-performance aerogels with adjustable geometries for electronic, biomedical, and environmental applications is presented.