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<p>Poly(vinylidene fluoride) (PVDF), the most widely used ferroelectric polymer, typically exhibits a negligible electrocaloric effect (ECE) due to its symmetrical molecular configuration and bulky ferroelectric domains. PVDF-based ferroelectric terpolymers with giant ECE are expensive and have a narrow temperature window (<i>T</i><sub>w</sub>). Here, we report that PVDF films prepared by solid-phase pressure forming (PVDF-SPF) show a giant ECE of up to 12.8 K at 25 °C and a wide <i>T</i><sub>w</sub> of 60 °C. PVDF films underwent significant plastic deformation and extensive crystal fragmentation, forming loose and tiny β crystal grains under 30 MPa solid-phase pressure. The giant ECE primarily originates from orientation entropy changes of molecular chains associated with the reversible transition between loose and compact β crystals, as well as switching entropy changes of polar dipoles in tiny grains. Given the availability of PVDF, this work opens a route for the development of scalable solid-state cooling techniques.</p>

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From negligible to giant electrocaloric effect of poly(vinylidene fluoride)

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年12月17日

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  • Yibo Zhang,
  • Zhiwei Ye,
  • Fukun Niu,
  • Chuanxi Xiong,
  • Wei Wang,
  • Yuheng Fu,
  • Shixian Zhang,
  • Shan Wang,
  • Quanling Yang,
  • Hongmei Qin,
  • Shuang Liu,
  • Qing Wang

摘要

Poly(vinylidene fluoride) (PVDF), the most widely used ferroelectric polymer, typically exhibits a negligible electrocaloric effect (ECE) due to its symmetrical molecular configuration and bulky ferroelectric domains. PVDF-based ferroelectric terpolymers with giant ECE are expensive and have a narrow temperature window (Tw). Here, we report that PVDF films prepared by solid-phase pressure forming (PVDF-SPF) show a giant ECE of up to 12.8 K at 25 °C and a wide Tw of 60 °C. PVDF films underwent significant plastic deformation and extensive crystal fragmentation, forming loose and tiny β crystal grains under 30 MPa solid-phase pressure. The giant ECE primarily originates from orientation entropy changes of molecular chains associated with the reversible transition between loose and compact β crystals, as well as switching entropy changes of polar dipoles in tiny grains. Given the availability of PVDF, this work opens a route for the development of scalable solid-state cooling techniques.