From Tanghulu-like to Cattail-like SiC Nanowire Architectures: Interfacial Design of Nanocellulose Composites toward Highly Thermal Conductivity
The development of polymer-based thermal management materials (TMMs) is crucial to address the frequency reduction or overheating damage of modern electronics caused by inadequate thermal conductivity of substrates. However, high interfacial thermal resistance between filler and filler or between filler and matrix creates paramount bottlenecks for the prominent thermal conduction in polymer-based composites. Herein, novel Tanghulu-like MoS2-SiC nanowire (L-MoS2-SiCNW) and Cattail-like H-MoS2-SiCNW hybrids are successfully fabricated via a facile hydrothermal method, and then incorporated into green cellulose nanofiber (CNF) matrix by a vacuum-assisted filtration approach. In H-MoS2-SiCNW hybrids, SiCNWs and MoS2 nanosheets are mimicking the compact rachides and fluffy sheath-shaped inflorescences of Cattails, respectively. MoS2 nanosheets tightly rooted on the surface of SiCNWs can bridge the gap and increase the contact area between SiCNWs, which consequently leads to the large reduction of interfacial thermal resistance. Fitting the experimental thermal conductivity (TC) values with EMT model quantitatively illustrates that the interfacial thermal resistance between H-MoS2-SiCNWs and CNFs (Rc1=3.11×10-4 m2 K W-1) exhibits a 36.1% decrease, compared with that between bare SiCNWs and CNFs (Rc1=4.87×10-4 m2 K W-1). Notably, the filler-filler interfacial thermal resistance in CNF/H-MoS2-SiCNWs (Rc2=7.02×10-8 m2 K W-1) is exceptionally one order of magnitude lower than that of CNF/SiCNW (Rc2=4.23×10-7 m2 K W-1), according to Foygel model. As a result, the maximum in-plane TC of 19.76 W m-1 K-1 is attained for the flexible CNF/H-MoS2-SiCNW film at a relatively low filler content of 22.5 vol%, which has an enhancement of 1408% in contrast to that of pure CNF film. In addition, the volume resistivity of the flexible CNF/H-MoS2-SiCNW film (4.1×1012 Ω·cm) is two orders of magnitude higher than that of pure CNF (7.9×1010 Ω·cm), which is far above the required resistance for electrical insulation (1.0×109 Ω·cm). In the real TMM application measurement of CNF/H-MoS2-SiCNW, the temperature of CPU core with CNF/H-MoS2-SiCNW heat spreader is elevated more slowly than that of the bare case (e.g.: ∆=4.9 °C at 980 s). Thus, this investigation provides a valuable insight into the design and fabrication of favorable polymer-based TMMs for potential applications in microelectronics and advanced energy.
- This article is part of the themed collection: Journal of Materials Chemistry A HOT Papers