A Bioinspired Polymer‐Based Composite Displaying Both Strong Adhesion and Anisotropic Thermal Conductivity

Abstract The integration and functionality of high‐power electronic architectures or devices require a high strength and good heat flow at the interface. However, simultaneously improving the interfacial bonding and phonon transport of polymers is challenging because of the tradeoff between the cross‐linked flexible chains and high‐quality crystalline structure. Here, a copolymer, poly(dopamine methacrylate‐co‐hydroxyethyl methacrylate [P(DMA‐HEMA)] is designed and synthesized, inspired by the snail and mussel adhesion. The copolymer achievs a high surface adhesion up to 6.38 MPa owing to the synergistic effects of hydrogen bonds and mechanical interlocking. When the copolymer is introduced into vertically aligned carbon nanotubes (VACNTs), the catechol groups in P(DMA‐HEMA) formed strong bonding with the nanotubes through π‐π interactions at the interface. As a result, the P(DMA‐HEMA)/VACNTs composite shows a high through‐plane thermal conductivity (21.46 W m −1 K −1 ), an in‐plane thermal conductivity that is 3.5 times higher than that of pristine VACNTs, and an extremely low thermal contact resistance (20.27 K mm 2 W −1 ). Furthermore, the composite forms weld‐free high‐strength connections between two pieces of various metals to bridge directional thermal pathways. It also exhibits excellent interfacial heat transfer capability and high reliability even under zero‐pressure conditions.