Beyond β‐Phase Fraction: Structure–Property Relationships in Corona‐Poled Poly(Vinylidene Fluoride)/Titanium Dioxide Nanocomposite Films

Poly(vinylidene fluoride) (PVDF)/titanium dioxide (TiO 2 ) composite films were fabricated by solution casting from N,N‐dimethylformamide (DMF) with TiO 2 loadings of 0, 1, 5, 10, and 15 wt%. Scanning electron microscopy (SEM), x‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), and d 33 measurements were carried out to study the effect of TiO 2 loading in terms of morphology, crystalline structure, electroactive fraction of the β‐phase, and piezoelectric response. The β‐phase fraction increased from 79.88% for pristine PVDF to 90.27% at 15 wt% TiO 2 . In contrast, the highest measured d 33 was 34 ± 1.70 pC/N at 10 wt% TiO 2 , compared with 20 ± 1.00 pC/N for pristine PVDF. At this composition, the XRD‐derived relative crystallinity reached 74%, and the FWHM decreased to 1.98°. At 15 wt% TiO 2 , the d 33 decreased to 30 ± 1.50 pC/N despite the higher β‐phase fraction, accompanied by lower crystallinity and greater morphological heterogeneity. Because film thickness increased with TiO 2 loading, the piezoelectric results are interpreted as composition‐dependent structure–property relationships under the employed processing and film‐thickness conditions.