One-Dimensional Polarization Dynamics in Ferroelectric Polymers

Anwar, Saleem; Asadi, Kamal

doi:10.1021/acsmacrolett.9b00166

Cited by 18 publications

(11 citation statements)

References 29 publications

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“…The rigid tilting of the whole chain is difficult to imagine. Rather, the tilting of a finite chain segment is speculated to occur through the generation of the local kinks along the chain axis. ,,− For example, in the case of a planar zigzag chain of all-trans conformation, the local generation of TG and TG̅ bonds is said to produce the kinks that cause the tilting of the stems. ,, Besides the dipole moments must change the direction in this process. That is to say, the tilting motion and the rotational motion must be coupled through the T-G conformational exchange.…”

Section: Resultsmentioning

confidence: 99%

High-Electric-Field-Induced Hierarchical Structure Change of Poly(vinylidene fluoride) as Studied by the Simultaneous Time-Resolved WAXD/SAXS/FTIR Measurements and Computer Simulations

et al. 2021

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A high electric field was applied cyclically to poly(vinylidene fluoride) films, during which the simultaneous and time-resolved measurements of the two-dimensional wideangle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), and transmission-type Fourier transform infrared (FTIR) spectra were performed using a synchrotron X-ray radiation system. The inversion of the CF 2 dipole moments caused by the alternate change of the electric field vector direction was detected to occur around ±80−100 MV/m as estimated by the electricfield-strength dependence of the IR band intensity. On the other hand, the WAXD peaks were found to show the maximal intensities at 0 and ±250−300 MV/m. In these regions, the 001 reflection of the β form and the 002 reflection of the δ form changed the intensities remarkably and periodically. These experimental data were interpreted, not by the idea of a simple inversion motion of the rigid polar chains (the planar zigzag chains of the form β and the TGTG̅ chains of the α and δ forms) but by the more complicated couplings between the rotation and tilting motions of the chain segments, the cooperative T-G conformational exchanges, and the associated inversion motion of the CF 2 dipoles. The idea of the cooperative chain motions was supported by the density functional theory calculations performed under the external electric field. Different from the remarkable changes of the WAXD and FTIR data, the SAXS patterns did not show the detectable changes in these processes, indicating that the above-mentioned cooperative structural changes should occur in the crystalline regions with the stacked lamellar structure kept unchanged.

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Section: Resultsmentioning

confidence: 99%

High-Electric-Field-Induced Hierarchical Structure Change of Poly(vinylidene fluoride) as Studied by the Simultaneous Time-Resolved WAXD/SAXS/FTIR Measurements and Computer Simulations

et al. 2021

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“…The domain velocity data well fits in the classical creep formula for disordered elastic media shown in Equation () [ 60–62 ] . The creep or the domain evolution behavior is due to the presence of randomly pinned potential in a disordered system.…”

Section: Resultsmentioning

confidence: 63%

Robust Polarization Stability in a Self‐Assembled Ultrathin Organic Ferroelectric Nano Lamellae

Viswanath

Silva

Morikuni

et al. 2021

Adv Elect Materials

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Spontaneous polarization is a characteristic feature of a ferroelectric material that can be switched by the application of an external electric field. However, in a practical scenario, the switched polarization should be stable for the realization of functional devices. In this study, an ultrathin (≈40 nm) poly(vinylidene fluoride‐trifluoroethylene (PVDF‐TrFE) film self‐assembled on a monolayer (≈1 nm) graphene oxide (GO) film is exploited. Oxygen‐functional groups and defective structure of GO can act as domain pinning sites to provide strong ferroelectric domain stability along with a specific crystal orientation to PVDF‐TrFE through hydrogen bonds and columbic interactions. Scanning probe microscopy based switching experiments reveal excellent piezoelectric response (d33 = −145 pm V−1) along with high polarization retention (over 1500 h with no volatilization) in these ultrathin films, paving new pathways toward high performance miniaturized organic ferroelectric devices.

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“…The dashed lines in Figure 12 c are the fitting curves in order to indicate that the KAI model can fit the experimental data. The dimensionality of the switching mechanism in ferroelectric polymers is still unclear, and several works have been published during the last few years trying to solve or explain this issue [ 66 , 67 , 68 , 69 ]. The study of the dimensionality of the switching mechanism is outside the scope of this work.…”

Section: Resultsmentioning

confidence: 99%

Effect of the TrFE Content on the Crystallization and SSA Thermal Fractionation of P(VDF-co-TrFE) Copolymers

María

Goupil

Cavallo

et al. 2022

IJMS

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In this contribution, we study the effect of trifluoro ethylene (TrFE) comonomer content (samples with 80/20, 75/25, and 70/30 VDF/TrFE molar ratios were used) on the crystallization in P(VDF-co-TrFE) in comparison with a PVDF (Poly(vinylidene fluoride)) homopolymer. Employing Polarized Light Optical Microscopy (PLOM), the growth rates of spherulites or axialites were determined. Differential Scanning Calorimetry (DSC) was used to determine overall crystallization rates, self-nucleation, and Successive Self-nucleation and Annealing (SSA) thermal fractionation. The ferroelectric character of the samples was explored by polarization measurements. The results indicate that TrFE inclusion can limit the overall crystallization of the copolymer samples, especially for the ones with 20 and 25% TrFE. Self-nucleation measurements in PVDF indicate that the homopolymer can be self-nucleated, exhibiting the classic three Domains. However, the increased nucleation capacity in the copolymers provokes the absence of the self-nucleation Domain II. The PVDF displays a monomodal distribution of thermal fractions after SSA, but the P(VDF-co-TrFE) copolymers do not experience thermal fractionation, apparently due to TrFE incorporation in the PVDF crystals. Finally, the maximum and remnant polarization increases with increasing TrFE content up to a maximum of 25% TrFE content, after which it starts to decrease due to the lower dipole moment of the TrFE defect inclusion within the PVDF crystals.

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One-Dimensional Polarization Dynamics in Ferroelectric Polymers

Cited by 18 publications

References 29 publications

High-Electric-Field-Induced Hierarchical Structure Change of Poly(vinylidene fluoride) as Studied by the Simultaneous Time-Resolved WAXD/SAXS/FTIR Measurements and Computer Simulations

High-Electric-Field-Induced Hierarchical Structure Change of Poly(vinylidene fluoride) as Studied by the Simultaneous Time-Resolved WAXD/SAXS/FTIR Measurements and Computer Simulations

Robust Polarization Stability in a Self‐Assembled Ultrathin Organic Ferroelectric Nano Lamellae

Effect of the TrFE Content on the Crystallization and SSA Thermal Fractionation of P(VDF-co-TrFE) Copolymers

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