Naturally derived nano-ceramic composites with enhanced dielectric performance for electronics applications

Polydimethylsiloxane (PDMS) is a widely used elastomer for flexible electronics, but its low dielectric permittivity limits charge storage and sensitivity in capacitive devices. In this study, a sustainable CaO-rich filler, Naturally Extracted Dielectric (NED)—was produced from biowaste cuttlefish bone via calcination and incorporated into PDMS to fabricate Flexible Composite Films (FCF). The PDMS and NED composite was prepared by solution casting with controlled loadings (2.5, 5, 7.5, and 10 wt.%). The structural and chemical integrity were confirmed by X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR), indicating successful filler incorporation without the formation of new phases of the PDMS network. Optical analysis showed a wide band gap (~ 3.27–3.33 eV), consistent with dielectric behavior. Scanning Electron Microscopy (SEM) with Energy-Dispersive X-ray Spectroscopy (EDS) revealed dispersed filler domains with increasing surface roughness and mild agglomeration at 10 wt.% NED. Impedance spectroscopy showed depressed semicircles well fitted by a Bulk resistance (Rb) parallel with Constant Phase Element (CPE) model, indicating bulk-controlled, non-Debye relaxation; bulk resistance decreased to a minimum at 7.5 wt.% and slightly increased at 10 wt.% due to microstructural limitation. Dielectric spectra exhibited strong low-frequency interfacial polarization, with dielectric loss of 0.13–0.18 in of mid-frequency range. Overall, the optimized PDMS:NED composition (notably 7.5 wt.%) provides a promising flexible dielectric platform for capacitive pressure sensors and wearable electronics applications. Also, as a dielectric and tribo-layer candidate for triboelectric nanogenerators (TENGs), where permittivity and interfacial polarization are performance-relevant.