The valorization of industrial waste streams into functional electronic materials offers a sustainable route for developing advanced polymer composites. In this work, calcium fluoride (CaF \(_2\) ) nanoparticles were synthesized from industrial hexafluorosilicic acid (H \(_2\) SiF \(_6\) ) via a precipitation route and employed as fillers in polyvinylidene fluoride (PVDF) to fabricate dielectric nanocomposites. Structural characterization confirmed the formation of crystalline cubic CaF \(_2\) nanoparticles with average particle sizes in the range of 30–50 nm. Energy-dispersive X-ray spectroscopy revealed the presence of calcium and fluorine as the major constituents, along with weak silicon and oxygen signals attributed to trace amorphous silica residues originating from the hydrolysis of the H \(_2\) SiF \(_6\) precursor. PVDF/CaF \(_2\) composite films containing up to 20 wt% filler were prepared using a solution casting method and their dielectric properties were investigated over a frequency range of \(10^{2}\) – \(10^{6}\) Hz. Compared with pristine PVDF, which exhibits a relative permittivity of approximately 10 at 1 kHz, the nanocomposites display a significant enhancement in low-frequency dielectric constant, approaching values close to \(\sim \) 200 at 100 Hz for composites containing 20 wt% CaF \(_2\) . The dielectric constant decreases with increasing frequency, while dielectric loss and AC conductivity show moderate increases with filler loading. The observed dielectric behavior is primarily associated with Maxwell–Wagner–Sillars interfacial polarization arising from the heterogeneous structure and large interfacial area between the PVDF matrix and dispersed CaF \(_2\) nanoparticles. These results indicate that waste-derived CaF \(_2\) nanoparticles can serve as cost-effective fillers for modifying the dielectric response of PVDF-based composites, while simultaneously providing a sustainable pathway for utilizing industrial byproducts in electronic materials.
