Mussel Inspired Modification for Aluminum Oxide/Silicone Elastomer Composites with Largely Improved Thermal Conductivity and Low Dielectric Constant

Inspired by unparalleled adhesion of mussels, bioinspired poly(dopamine) (PDA) has been used to functionalize the surface of aluminum oxide (Al2O3) nanoparticles aiming at improving the thermal conductivity of silicone rubber (SR). The successful and effective preparation of PDA modified Al2O3 nanoparticles (Al2O3–PDA) was confirmed by XPS, HR-TEM, and XRD. The PDA coating on the Al2O3 nanoparticles improved its interfacial interaction between polymeric matrix and facilitated the uniform-dispersion of filler, leading to the 30 vol % Al2O3–PDA/SR composite that exhibited a high thermal conductivity (0.585 W/((m·K))), which was almost 400% of pure silicone rubber (0.147 W/(m·K)). In addition, the 30 vol % Al2O3–PDA/SR composite displayed a relatively low dielectric constant (4.06 at 1 kHz), which was a bit higher than that of pure SR (2.59 at 1 kHz), a big advantage for the electronic or electrical engineering application. With advantages of efficient, easy handling, controllable, and eco-friendly, this modification method provides a new universal route to improve the thermal conductivity of composites.