Abstract:

The development of multifunctional flexible composites integrating efficient electromagnetic wave absorption (EMA) and thermal management is critical for modern high-frequency electronic devices. However, conventional carbon-based materials face an inherent trade-off between dielectric loss and thermal conductivity. Herein, we fabricate a flexible poly(vinylidene fluoride) (PVDF) composite incorporated with a hybrid nanofiller denoted as CH@MCOOH. This filler comprises semiconducting copper-based metal–organic frameworks (CH) grown in situ on carboxylated multi-walled carbon nanotubes (MCOOH). The tailored CH@MCOOH hybrid filler enables effective dielectric modulation through coordination bond-driven interfacial electron redistribution, which optimizes the electrical properties of carbon nanotubes by suppressing excessive conductivity while enhancing polarization relaxation. This process ensures excellent impedance matching even at elevated filler loadings. Simultaneously, the uniformly dispersed fillers construct continuous thermally conductive pathways within the PVDF fiber network, significantly enhancing the thermal conductivity. Moreover, the incorporation of CH@MCOOH promotes the formation of electroactive β-phase PVDF, which further augments polarization loss. The resulting composite demonstrates exceptional EMA performance, achieving a minimum reflection loss of ?45.32 dB at the thickness of 3.0 mm, and a superior in-plane thermal conductivity of 0.74 W m?1 K?1, outperforming currently reported carbon-based counterparts. This work provides a feasible strategy for designing carbon-based polymer composites with tailored dielectric properties for simultaneous EMA and thermal management.