Study on the Enhancement of Thermal‐Conductive and Mechanical Properties of PVA Composite Films by PDA/h‐BN@SiO2 Functional Filler

ABSTRACT With ongoing trends toward miniaturization, high integration, and foldability in electronics, the demand for efficient thermal management has increased significantly. Developing electrically insulating thermal interface materials featuring high effective thermal conductivity (ETC) is therefore essential. In this work, hexagonal boron nitride (h‐BN) was adjusted with dopamine hydrochloride (DA·HCl) and coated with nano‐silica (SiO 2 ) to produce a polydopamine‐modified h‐BN‐supported silica (PDA/h‐BN@SiO 2 ) functional filler. This filler was incorporated into polyvinyl alcohol (PVA) by physical blending to fabricate PDA/h‐BN@SiO 2 /PVA composite films. XRD, XPS, and FTIR confirmed the successful synthesis of the functional filler. TC studies revealed that the composite film containing 2 wt% filler had a higher in‐plane ETC of 2.32 W·m −1 ·K −1 as opposed to 0.32 W·m −1 ·K −1 , corresponding to a 605.17% increase relative to pure PVA. While the through‐plane ETC achieved a value of 0.58 W·m −1 ·K −1 higher than 0.28 W·m −1 ·K −1 , representing a 107.14% increase compared to that of pure PVA. Thermogravimetric analysis revealed improved thermal stability. Mechanical testing indicated that the tensile strength rose from 45.45 MPa (pure PVA) to 66.28 MPa (2 wt% composite), a 45.83% improvement. These results demonstrate that PDA/h‐BN@SiO 2 enhances both in‐plane ETC and through‐plane ETC, as well as mechanical strength of PVA, offering a promising strategy for the superior performance of thermal interface materials.