From negligible to giant electrocaloric effect of poly(vinylidene fluoride).
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41407827.
- Also identified by DOI 10.1038/s41467-025-66151-7 and PMC identifier 12712024.
- Licence recorded as CC BY-NC-ND.
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Abstract
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 (T<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 T<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.