Effect of the Preparation Process on the Structure andProperties of the STTO/PVDF Composites

Author of the article:NI Lei1, MA Yingying1, CHANG Rong1, MENG Ruixi1, LIN Yuxin1, ZHONG Hong2

Author's Workplace：1. School of Materials Science and Engineering，Chang'an University, Xi'an 710018, China; 2. State Key Laboratory ofSolidification Processing, Northwestern Polytechnical University, Xi'an 710072, China

Key Words：STTO/PVDF composite materials; hot pressing method; casting method

Abstract：To meet the demand for high-performance flexible dielectric materials in microelectronics, giant-dielectric(Sm0.5Ta0.5)0.04Ti0.96O2 (STTO) ceramics were employed as fillers, and polyvinylidene fluoride (PVDF) was used as thepolymer matrix. STTO/PVDF composites with varying filler volume fractions were prepared via hot-pressing andtape-casting routes, with the aim of systematically investigating the synergistic effects of processing methods and materialcomposition on the microstructure and dielectric properties of the composites. The hot-pressed composites predominantlycontained α-phase PVDF, whereas the tape-cast samples contained both α- and β-phase crystals. With increasing STTOcontent, both types of composites display aggravated filler agglomeration and interfacial defects; however, the tape-castsamples demonstrate superior microstructural densification. The tape-cast composites achieve a relatively high breakdownstrength, ranging from 235.3 kV/mm to 97.7 kV/mm, whereas the hot-pressed composites exhibit superior dielectricperformance, with a higher dielectric constant (10.0~60.4) and lower dielectric loss (0.02~0.26). This work clarifies thedistinct advantages of these two processing routes: hot pressing is more suitable for applications requiring high permittivity,whereas tape casting is preferable for insulation-critical scenarios requiring high breakdown strength.