posted on 2024-01-26, 11:04authored byMuhua Yuan, Haijun Wang, Yuxin Wang, Ji Li, Chunlei Yuan, Xiaoli Sun, Jian Hu, Shaojuan Wang, Shouke Yan
Due
to the high activating energy, it is very difficult to initiate
the α-to-γ phase transition of poly(vinylidene fluoride)
(PVDF), resulting in an extremely slow transition rate. Here, introducing
a small number of double bonds into the PVDF molecular chains through
dehydrofluorination is demonstrated to markedly decrease the activating
energy and enhance the phase transition efficiency. It is found that
the introduced double bonds during the dehydrofluorination reaction
accelerate the α-to-γ phase transition, which is reflected
by the shortened induction period and increased transition rate. The
α-to-γ phase transition in PVDF modified with double bonds
occurs mostly from the nuclei of α-spherulites rather than from
the scarce boundaries initiated by γ-spherulites as in unmodified
PVDF. Comparative analysis reveals that the energy storage performance
of γ-PVDF films prepared through the phase transition surpasses
that of α-PVDF ones. Compared to α-PVDF, the energy storage
density of the modified γ-PVDF exhibits a remarkable enhancement
of 181%, while the energy storage efficiency experiences a notable
improvement of 124%. Consequently, a molecular modification strategy
for the α-to-γ phase transition is introduced, enabling
efficient production of γ-PVDF with enhanced energy storage
properties and positioning it as an ideal material for driving technological
advancements in electronic devices, electric vehicles, and renewable
energy sectors.