Thermal Behavior, Local-Scale Morphology, and Phase Composition of Spherulites in Melt-Crystallized Poly(Vinylidene Fluoride) Films
Synchrotron microbeam X-ray diffraction was employed to investigate the local-scale structure and solid-state phase transformation within individual spherulites of poly(vinylidene fluoride) (PVDF). In thin, non-oriented films, PVDF crystallizes into α and γ-phases, forming distinct spherulitic morph...
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2025-01-01
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| author | Denis V. Anokhin Dana S. Plieva Martin Rosenthal Andrei V. Churakov Dimitri A. Ivanov |
| author_facet | Denis V. Anokhin Dana S. Plieva Martin Rosenthal Andrei V. Churakov Dimitri A. Ivanov |
| author_sort | Denis V. Anokhin |
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| description | Synchrotron microbeam X-ray diffraction was employed to investigate the local-scale structure and solid-state phase transformation within individual spherulites of poly(vinylidene fluoride) (PVDF). In thin, non-oriented films, PVDF crystallizes into α and γ-phases, forming distinct spherulitic morphologies: large, banded α-spherulites and smaller, irregular “mixed” spherulites dominated by the γ-phase. For samples crystallized at high undercooling (160 °C), the mixed spherulites primarily consisted of the γ-phase, with only a minor fraction of α-lamellae localized at the spherulite boundaries. At higher crystallization temperatures (165 °C), the α-phase was entirely absent from the mixed spherulites. High-temperature annealing induced a phase transformation from the α-phase to the γ-phase, initiating at the interface between α- and γ-spherulites. The transformation propagated radially along the <i>b</i>-axis of the α-spherulite, while its characteristic banded morphology remained intact. Radial scanning with an X-ray microbeam provided spatially resolved mapping of the structural transition within the α-spherulite at the micrometer scale, offering detailed insights into the transformation mechanism and its impact on the spherulitic structure. The fast crystal growth direction remained unaltered during the transition, suggesting minimal material transport and maintaining structural coherence. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-4e7070d821e348b2bfeb45f1e47912352025-01-24T13:28:17ZengMDPI AGCrystals2073-43522025-01-011519410.3390/cryst15010094Thermal Behavior, Local-Scale Morphology, and Phase Composition of Spherulites in Melt-Crystallized Poly(Vinylidene Fluoride) FilmsDenis V. Anokhin0Dana S. Plieva1Martin Rosenthal2Andrei V. Churakov3Dimitri A. Ivanov4Faculty of Chemistry, Lomonosov Moscow State University, GSP-1, 1–3 Leninskiye Gory, 119991 Moscow, RussiaFaculty of Chemistry, Lomonosov Moscow State University, GSP-1, 1–3 Leninskiye Gory, 119991 Moscow, RussiaFaculty of Chemistry, KU Leuven, Celestijnenlaan 200F, Box 2404, B-3001 Leuven, BelgiumFaculty of Chemistry, Lomonosov Moscow State University, GSP-1, 1–3 Leninskiye Gory, 119991 Moscow, RussiaFaculty of Chemistry, Lomonosov Moscow State University, GSP-1, 1–3 Leninskiye Gory, 119991 Moscow, RussiaSynchrotron microbeam X-ray diffraction was employed to investigate the local-scale structure and solid-state phase transformation within individual spherulites of poly(vinylidene fluoride) (PVDF). In thin, non-oriented films, PVDF crystallizes into α and γ-phases, forming distinct spherulitic morphologies: large, banded α-spherulites and smaller, irregular “mixed” spherulites dominated by the γ-phase. For samples crystallized at high undercooling (160 °C), the mixed spherulites primarily consisted of the γ-phase, with only a minor fraction of α-lamellae localized at the spherulite boundaries. At higher crystallization temperatures (165 °C), the α-phase was entirely absent from the mixed spherulites. High-temperature annealing induced a phase transformation from the α-phase to the γ-phase, initiating at the interface between α- and γ-spherulites. The transformation propagated radially along the <i>b</i>-axis of the α-spherulite, while its characteristic banded morphology remained intact. Radial scanning with an X-ray microbeam provided spatially resolved mapping of the structural transition within the α-spherulite at the micrometer scale, offering detailed insights into the transformation mechanism and its impact on the spherulitic structure. The fast crystal growth direction remained unaltered during the transition, suggesting minimal material transport and maintaining structural coherence.https://www.mdpi.com/2073-4352/15/1/94poly(vinylidene fluoride)banded spherulitescrystal–crystal transitionpolarized optical microscopymicrofocus X-ray diffractionatomic force microscopy |
| spellingShingle | Denis V. Anokhin Dana S. Plieva Martin Rosenthal Andrei V. Churakov Dimitri A. Ivanov Thermal Behavior, Local-Scale Morphology, and Phase Composition of Spherulites in Melt-Crystallized Poly(Vinylidene Fluoride) Films Crystals poly(vinylidene fluoride) banded spherulites crystal–crystal transition polarized optical microscopy microfocus X-ray diffraction atomic force microscopy |
| title | Thermal Behavior, Local-Scale Morphology, and Phase Composition of Spherulites in Melt-Crystallized Poly(Vinylidene Fluoride) Films |
| title_full | Thermal Behavior, Local-Scale Morphology, and Phase Composition of Spherulites in Melt-Crystallized Poly(Vinylidene Fluoride) Films |
| title_fullStr | Thermal Behavior, Local-Scale Morphology, and Phase Composition of Spherulites in Melt-Crystallized Poly(Vinylidene Fluoride) Films |
| title_full_unstemmed | Thermal Behavior, Local-Scale Morphology, and Phase Composition of Spherulites in Melt-Crystallized Poly(Vinylidene Fluoride) Films |
| title_short | Thermal Behavior, Local-Scale Morphology, and Phase Composition of Spherulites in Melt-Crystallized Poly(Vinylidene Fluoride) Films |
| title_sort | thermal behavior local scale morphology and phase composition of spherulites in melt crystallized poly vinylidene fluoride films |
| topic | poly(vinylidene fluoride) banded spherulites crystal–crystal transition polarized optical microscopy microfocus X-ray diffraction atomic force microscopy |
| url | https://www.mdpi.com/2073-4352/15/1/94 |
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