Multiamino Polydiacetylene-Mediated Interfacial Engineering of Boron Nitride Nanosheet/Polyimide Composites for Low-Dielectric Thermal Management

The rapid advancement of high-frequency and highly integrated semiconductor devices urgently calls for dielectric materials that combine high thermal conductivity, low dielectric constant, and excellent thermal stability. Herein, multiamino polydiacetylene-functionalized boron nitride nanosheets (BNNS@MAPDA) have been incorporated into a MAPDA-containing polyimide matrix to improve filler–matrix interfacial coupling. The functionalized nanosheets exhibit high aspect ratios, few lattice defects, high yields, and excellent dispersion in the PI-MAPDA matrix. At a filler loading of only 7.5 wt %, the PI‑MAPDA/BNNS@MAPDA‑7.5 composite film achieves an in‑plane thermal conductivity of 1.67 W m–1 K–1, representing a 422% enhancement over pristine PI‑MAPDA. Benefiting from the ultralow polarizability of fluorinated groups and the strengthened interfacial coupling, the nanocomposite simultaneously maintains a low dielectric constant of 2.20 and a low dielectric loss tangent (tanδ) of 0.0066 at 1 MHz, alongside a volume resistivity of 9.7 × 1011 Ω cm. The density functional theory (DFT) calculations reveal that MAPDA functionalization enhances interfacial affinity and energy transfer, while molecular dynamics (MD) simulations elucidate its influence on thermal conductivity and dielectric properties. The Hashin–Shtrikman (HS) model analysis further confirms the positive role of interface regulation in thermal conductivity enhancement. MAPDA-mediated interphase engineering, through multisite anchoring to BNNS and strong chemical affinity with the PI matrix, provides an effective route to promote interfacial heat transfer while suppressing interfacial polarization at low filler loading. This material provides a promising solution for advanced electronic insulation and packaging applications by successfully addressing the challenge of combining low dielectric constant and high thermal conductivity in microelectronic systems.