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<p>Owing to the outstanding ferroelectric properties, PVDF and its copolymers have emerged as the most promising piezoelectric polymer materials to date. To enhance the dielectric constant of P(VDF-HFP) while reducing its dielectric loss, BT@C@SiO<sub>2</sub> with a double-layer shell structure was synthesized and blended with P(VDF-HFP) to fabricate a piezoelectric film. Under mild conditions, PDA was synthesized as the precursor of the conductive carbon inner shell, which was carried out in a weakly alkaline Tris buffer system at room temperature, only involving stirring, centrifugation, water washing, and low-temperature drying, without any drastic reaction procedures. The results demonstrated that the incorporation of BT increased the dielectric constant of the film, whereas the introduction of the C layer formed micro-capacitors within the matrix, further enhancing the dielectric constant. Simultaneously, the C layer with high defect density captured freely mobile carriers in the film, thereby reducing AC conductivity and dielectric loss, which improved the energy harvesting efficiency of the piezoelectric film. The dielectric constant of the BT@C@SiO<sub>2</sub>/P(VDF-HFP) film could reach up to 15.8 (100&#xa0;Hz), while the dielectric loss and conductivity were as low as 0.042 and 3.77 × 10<sup>–9</sup>&#xa0;S/m (100&#xa0;Hz), respectively. The BT@C@SiO<sub>2</sub> acted as a nucleating agent in the P(VDF-HFP) matrix, and consequently induced the increase of the crystallization temperature and the formation of β phase in P(VDF-HFP). When the BT@C@SiO<sub>2</sub> content reached 5%, under a pressure of 40&#xa0;N and a loaded resistance of 10<sup>6</sup>&#xa0;Ω, the composite film achieved its highest piezoelectric output with the output voltage of 1.1&#xa0;V. Under a pressure of 40&#xa0;N and a loaded resistance of 10<sup>11</sup>&#xa0;Ω, the piezoelectric output power reached its maximum value of 8.76&#xa0;μW. A 5% BT@C@SiO<sub>2</sub>/P(VDF-HFP) film was fabricated into a piezoelectric sensor for practical applications. The output voltages of the film during finger bending, finger tapping and foot stepping were 0.40&#xa0;V, 0.75&#xa0;V, and 2.65&#xa0;V, respectively. These results indicated that BT@C@SiO<sub>2</sub>/P(VDF-HFP) piezoelectric film exhibited potential application in motion monitoring.</p>

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BT@C@SiO₂ double-layer core-shell structure for enhancing the dielectric and piezoelectric properties of P(VDF-HFP) composite films

  • 期刊论文

  • 发表日期：

    2026年7月14日

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  • Bowen Yang,
  • Siqi Zhang,
  • Mengxiang Guan,
  • Lei Liu,
  • Ziyu Yan,
  • Yongri Liang,
  • Guirong Peng,
  • Zhe Zhou

摘要

Owing to the outstanding ferroelectric properties, PVDF and its copolymers have emerged as the most promising piezoelectric polymer materials to date. To enhance the dielectric constant of P(VDF-HFP) while reducing its dielectric loss, BT@C@SiO2 with a double-layer shell structure was synthesized and blended with P(VDF-HFP) to fabricate a piezoelectric film. Under mild conditions, PDA was synthesized as the precursor of the conductive carbon inner shell, which was carried out in a weakly alkaline Tris buffer system at room temperature, only involving stirring, centrifugation, water washing, and low-temperature drying, without any drastic reaction procedures. The results demonstrated that the incorporation of BT increased the dielectric constant of the film, whereas the introduction of the C layer formed micro-capacitors within the matrix, further enhancing the dielectric constant. Simultaneously, the C layer with high defect density captured freely mobile carriers in the film, thereby reducing AC conductivity and dielectric loss, which improved the energy harvesting efficiency of the piezoelectric film. The dielectric constant of the BT@C@SiO2/P(VDF-HFP) film could reach up to 15.8 (100 Hz), while the dielectric loss and conductivity were as low as 0.042 and 3.77 × 10–9 S/m (100 Hz), respectively. The BT@C@SiO2 acted as a nucleating agent in the P(VDF-HFP) matrix, and consequently induced the increase of the crystallization temperature and the formation of β phase in P(VDF-HFP). When the BT@C@SiO2 content reached 5%, under a pressure of 40 N and a loaded resistance of 106 Ω, the composite film achieved its highest piezoelectric output with the output voltage of 1.1 V. Under a pressure of 40 N and a loaded resistance of 1011 Ω, the piezoelectric output power reached its maximum value of 8.76 μW. A 5% BT@C@SiO2/P(VDF-HFP) film was fabricated into a piezoelectric sensor for practical applications. The output voltages of the film during finger bending, finger tapping and foot stepping were 0.40 V, 0.75 V, and 2.65 V, respectively. These results indicated that BT@C@SiO2/P(VDF-HFP) piezoelectric film exhibited potential application in motion monitoring.