Two‐dimensional Ti 3 C 2 T x /poly(vinylidene fluoride) metacomposites with weakly negative permittivity

2020 ◽  
Vol 41 (5) ◽  
pp. 1820-1829 ◽  
Author(s):  
Yuliang Zhang ◽  
Kuan Yin ◽  
Kai Sun ◽  
Shengjia Cao ◽  
Fujun Tao ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Negative Permittivity ◽  
Two Dimensional ◽  
Poly Vinylidene Fluoride

Synthesis and two-dimensional NMR of highly aregic poly(vinylidene fluoride)

1985 ◽  
Vol 18 (6) ◽  
pp. 1354-1357 ◽  
Author(s):  
Rudolf E. Cais ◽  
Janet M. Kometani
Keyword(s):  
Vinylidene Fluoride ◽  
Two Dimensional ◽  
Poly Vinylidene Fluoride

Two-Dimensional Correlation Infrared Spectroscopic Study on the Crystallization and Gelation of Poly(Vinylidene Fluoride) in Cyclohexanone

2008 ◽  
Vol 62 (3) ◽  
pp. 295-301 ◽  
Author(s):  
Yun Peng ◽  
Bingjie Sun ◽  
Peiyi Wu
Keyword(s):  
Absorption Band ◽  
Room Temperature ◽  
Vinylidene Fluoride ◽  
Time Interval ◽  
Infrared Spectroscopic Study ◽  
Two Dimensional ◽  
Gelation Process ◽  
Poly Vinylidene Fluoride ◽  
Conformational Ordering ◽  
Ir Bands

Poly(vinylidene fluoride) (PVDF) converts easily into a thermo-reversible gel through crystallization by standing at room temperature in cyclohexanone. In this study, the Fourier transform infrared (FT-IR) spectra were measured continuously at room temperature during the conversion of the solution into a gel. The IR difference spectra derived from these spectra by absorbance subtraction clearly indicate the presence of PVDF α-crystallites in the gel due to the presence of absorption bands corresponding to the TG+TG− conformation of the α-phase. In the time interval from 25 to 45 min after the beginning of the experiment, the IR bands of PVDF increased dramatically, indicating the conversion of polymer chains from random statistical coils to the ordered TG+TG− conformation (α-form). In the time interval from 45 to 90 min, the IR bands of PVDF increased slowly, reflecting no further crystallization. Using two-dimensional (2D) IR analysis, it could be shown that the v(C=O)) absorption band of cyclohexanone changed during the gelation process. During the conformational ordering process (25–45 min), the v(C=O) absorption band of the cyclohexanone dimer (1707 cm−1) decreased while the corresponding band of the monomer at 1718 cm−1 increased. Furthermore, a new band at 1695 cm−1 increased, which could be assigned to C=O groups of the solvent interacting with the CF2 groups in the polymer chain. The bands of the crystalline PVDF share positive cross-peaks with the bands of cyclohexanone, which indicates that the chain of PVDF changed prior to the cyclohexanone molecules during the conformational ordering process. However, these positive cross-peaks disappeared during the crystallization process, which means that the chain of PVDF changed synchronously with the solvent molecules. As for the bands of PVDF chains, the band at 762 cm−1 varied prior to the bands at 873 cm−1 and 796 cm−1 during the conformational ordering process. The 762 cm−1 absorption is assigned to the CF2 group of PVDF, the 873 cm−1 absorption involves the C–C group of PVDF, and the 796 cm−1 band is attributed to the CH2 groups of PVDF. Thus, the CF2 functionalities change faster than the C–C and CH2 groups. However, the correlation cross-peaks between 762 cm−1 and 873 cm−1 and at 796 cm−1 disappeared during the later state of the gelation process. At the same time, the bands of PVDF and solvent still varied, which suggests that it is a physical interaction process between PVDF chain and solvent.

High dielectric constant and low dielectric loss poly(vinylidene fluoride) nanocomposites via a small loading of two-dimensional Bi2Te3@Al2O3 hexagonal nanoplates

2018 ◽  
Vol 6 (2) ◽  
pp. 271-279 ◽  
Author(s):  
Jianwen Chen ◽  
Xiucai Wang ◽  
Xinmei Yu ◽  
Lingmin Yao ◽  
Zhikui Duan ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Dielectric Constant ◽  
Vinylidene Fluoride ◽  
Nanocomposite Films ◽  
Two Dimensional ◽  
Low Dielectric ◽  
Poly Vinylidene Fluoride ◽  
High Dielectric ◽  
Hexagonal Nanoplates

Nanocomposite films with a small loading of two-dimensional Bi2Te3@Al2O3 hexagonal nanoplates exhibit a high dielectric constant of 140 and relatively low dielectric loss of 0.05 at 1 kHz.

scholarly journals Effect of the Two-Dimensional Magnetostrictive Fillers of CoFe2O4-Intercalated Graphene Oxide Sheets in 3-2 Type Poly(vinylidene fluoride)-Based Magnetoelectric Films

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1782
Author(s):  
Geunryeol Baek ◽  
Su-Chul Yang
Keyword(s):  
Graphene Oxide ◽  
Polymer Films ◽  
Vinylidene Fluoride ◽  
Lateral Size ◽  
Two Dimensional ◽  
Critical Determinant ◽  
Biomedical Sensing ◽  
Sensing Applications ◽  
Poly Vinylidene Fluoride ◽  
Dipole Alignment

In the last decade, magnetoelectric (ME) polymer films have been developed by including zero-dimensional or one-dimensional magnetostrictive fillers in a piezoelectric polymer matrix. Existing reports on ME polymer films reveal that the shape of the magnetostrictive fillers is a critical determinant of the polymeric phase conformation, strain transfer between the piezoelectric and magnetostrictive phases, and dipole alignment in the films. In this study, to investigate the effect of two-dimensional (2D) magnetostrictive fillers on piezoelectric, magnetic, and magnetoelectric responses, 3-2 type ME films were prepared using CoFe2O4-intercalated graphene oxide (CFO-i-GO) fillers and poly(vinylidene fluoride) (PVDF) polymers. The 2D fillers of CFO-i-GO were hydrothermally synthesized by CFO intercalation into the interlayers of GO sheets with different lateral sizes, which were controlled by ultrasonication treatment. It was found that the large-lateral-size GO (LGO), medium-lateral-size GO (MGO), and small-lateral-size GO (SGO) fillers in the PVDF-based ME films exhibited a lateral size effect on CFO intercalation, polymeric phase conformation, dipole alignment, and magnetoelectric responses. A maximum ME coefficient (αME) of 3.0 mV/cm∙Oe was achieved with a strong linearity (r2) of 0.9992 at an off-resonance frequency (f) of 1 kHz and applied direct current (dc) magnetic field (Hdc) of ± 1000 Oe. The 3-2 type polymer-based ME films with reliable ME responses have potential for use in high-feasibility ME devices for biomedical sensing applications.

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