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

Abstract

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.

High-Curie-Temperature Elastic Polymer Ferroelectric by Carbene Cross-Linking

“…The T c of the resultant films was found to be higher than that achieved in our previous work . However, it remains lower than that observed in the commercial P­(VDF-TrFE) 80/20 . The likely reason for this discrepancy can be attributed to defects arising from the “head–head” structure and DBs, which impact the formation of crystal size .…”

“…14 However, it remains lower than that observed in the commercial P(VDF-TrFE) 80/20. 35 The likely reason for this discrepancy can be attributed to defects arising from the "head−head" structure and DBs, which impact the formation of crystal size. 32 This effect leads to a reduction in both the T c and T m .…”

“…Additionally, the introduction of defect structures, such as the “head–head” structure or double bonds (DBs), − enhances stretchability and cross-linking reactivity. Considering the substantial VDF content in P­(VDF-TrFE) 80/20 and its tendency to give a high Curie temperature, coupled with its ability to form the β crystalline phase through a solution process, we opt for a linear P­(VDF-TrFE) 80/20 variant with a minor incorporation of DBs [P­(VDF-TrFE-DB)] as the base polymer ferroelectric. The introduction of DBs enhances reactivity, particularly when reacting with carbene structures, as compared to methylene (−CH 2 −) and methenyl (−CH−) groups.…”

Deciphering TrFE Fingerprints in P(VDF-TrFE) by Raman Spectroscopy: Defect Quantification and Morphotropic Phase Boundary

“…The values are plotted in Figure c, with χ c increasing up to 38% for a 30% TrFE content and decreasing to around 30% for 50% TrFE. A recent work by María et al reported on the crystallization kinetics of molten bulk P­(VDF-TrFE) copolymers, showing that the inclusion of TrFE inside the PVDF-crystals increased the nucleation rate and density . This work deals with solution cast and dried thin films in which solvent–polymer interactions are expected to have an important contribution.…”

Flexible Iron-On Sensor Embedded in Smart Sock for Gait Event Detection

“…During the ironing process, heat is transferred from the iron through the HTV and conductive fabric to the surface of the P (VDF-TrFE) fibers. The P (VDF-TrFE) material has a main curie temperature of approximately 125–135 °C and a melting point of approximately 149 °C. , Due to the HTV material requirements, ironing is performed at 160 °C which is above the melting point of P (VDF-TrFE). Figure S3 shows the surface temperatures of P (VDF-TrFE) during the iron-on process.…”