1D-Confinement Inhibits the Anomaly in Secondary Relaxation of a Fluorinated Polymer

Simavilla, David Nieto; Abate, Anabella A.; Liu, Jie; Geerts, Yves; Losada-Pérez, Patricia; Napolitano, Simone

doi:10.1021/acsmacrolett.1c00220

Cited by 3 publications

(4 citation statements)

References 33 publications

(46 reference statements)

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“…Comparing with previous literature reports, and taking into consideration the intensity and position of the peaks, we were able to assign the low-temperature process to the local β-relaxation of PVDF related to local motions of polar groups in the polymer [73][74][75][76]. As the temperature was further increased (T > −60 • C), the relaxation peaks suffered important changes.…”

Section: Dielectric Spectroscopy Studies In Pvdf and Its Copolymerssupporting

confidence: 67%

“…Just at the transition temperatures (~47-57 • C), a small kink can be detected in the relaxation plot. Finally, very recently, Napolitano and collaborators observed an anomalous behavior in the local relaxation of PVDF copolymers with hexafluoropropylene (HFP) [76]. In their work, the dielectric relaxation experiments showed that, in the vicinity of T g , the PVDF-HFP copolymers displayed a so-called "anomalous minimum" in the local relaxation.…”

Section: Dielectric Spectroscopy Studies In Pvdf and Its Copolymersmentioning

confidence: 98%

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Phase Transitions in Poly(vinylidene fluoride)/Polymethylene-Based Diblock Copolymers and Blends

et al. 2021

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The crystallization and morphology of two linear diblock copolymers based on polymethylene (PM) and poly(vinylidene fluoride) (PVDF) with compositions PM23-b-PVDF77 and PM38-b-PVDF62 (where the subscripts indicate the relative compositions in wt%) were compared with blends of neat components with identical compositions. The samples were studied by SAXS (Small Angle X-ray Scattering), WAXS (Wide Angle X-ray Scattering), PLOM (Polarized Light Optical Microscopy), TEM (Transmission Electron Microscopy), DSC (Differential Scanning Calorimetry), BDS (broadband dielectric spectroscopy), and FTIR (Fourier Transform Infrared Spectroscopy). The results showed that the blends are immiscible, while the diblock copolymers are miscible in the melt state (or very weakly segregated). The PVDF component crystallization was studied in detail. It was found that the polymorphic structure of PVDF was a strong function of its environment. The number of polymorphs and their amount depended on whether it was on its own as a homopolymer, as a block component in the diblock copolymers or as an immiscible phase in the blends. The cooling rate in non-isothermal crystallization or the crystallization temperature in isothermal tests also induced different polymorphic compositions in the PVDF crystals. As a result, we were able to produce samples with exclusive ferroelectric phases at specific preparation conditions, while others with mixtures of paraelectric and ferroelectric phases.

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Section: Dielectric Spectroscopy Studies In Pvdf and Its Copolymerssupporting

confidence: 67%

Section: Dielectric Spectroscopy Studies In Pvdf and Its Copolymersmentioning

confidence: 98%

Phase Transitions in Poly(vinylidene fluoride)/Polymethylene-Based Diblock Copolymers and Blends

et al. 2021

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“…Recently, the same group revealed that the exceptional secondary relaxation of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) behavior gradually vanished upon confinement at the nanoscale level. This was explained by the presence of adsorbing walls inducing an increase in T g , which counterbalanced the asymmetry in the double-well potential responsible for the molecular motion . The effect of roughness of substrate on the relaxation of P4ClS and P2VP was studied, as shown in Figure p,q.…”

Section: Interface Study By Model-based Measurementmentioning

confidence: 99%

“…This was explained by the presence of adsorbing walls inducing an increase in T g , which counterbalanced the asymmetry in the double-well potential responsible for the molecular motion. 268 The effect of roughness of substrate on the relaxation of P4ClS and P2VP was studied, 269 as shown in Figure 16p,q. The increase of roughness led to the fast relaxation of P4ClS and the asymmetric broadening of relaxation peaks toward high frequency but had little effect on the P2VP.…”

Section: Structure Orientation Of Functional Groups and Molecular Chainsmentioning

confidence: 99%

Polymer Nanocomposite Dielectrics: Understanding the Matrix/Particle Interface

et al. 2022

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Polymer nanocomposite dielectrics possess exceptional electric properties that are absent in the pristine dielectric polymers. The matrix/particle interface in polymer nanocomposite dielectrics is suggested to play decisive roles on the bulk material performance. Herein, we present a critical overview of recent research advances and important insights in understanding the matrix/particle interfacial characteristics in polymer nanocomposite dielectrics. The primary experimental strategies and stateof-the-art characterization techniques for resolving the local property− structure correlation of the matrix/particle interface are dissected in depth, with a focus on the characterization capabilities of each strategy or technique that other approaches cannot compete with. Limitations to each of the experimental strategy are evaluated as well. In the last section of this Review, we summarize and compare the three experimental strategies from multiple aspects and point out their advantages and disadvantages, critical issues, and possible experimental schemes to be established. Finally, the authors' personal viewpoints regarding the challenges of the existing experimental strategies are presented, and potential directions for the interface study are proposed for future research.

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Tracing the slow Arrhenius process deep in the glassy state–quantitative evaluation of the dielectric relaxation of bulk samples and thin polymer films in the temperature domain

Thoms,

Li,

Napolitano

2024

The Journal of Chemical Physics

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The slow Arrhenius process (SAP) is a dielectric mode connected to thermally activated equilibration mechanisms, allowing for a fast reduction in free energy in liquids and glasses. The SAP, however, is still poorly understood, and so far, this process has mainly been investigated at temperatures above the glass transition. By employing a combination of methods to analyze dielectric measurements under both isochronal and isothermal conditions, we were able to quantitatively reproduce the dielectric response of the SAP of different polymers and to expand the experimental regime over which this process can be observed down to lower temperatures, up to 70 K below the glass transition. Employing thin films of thicknesses varying between 10 and 800 nm, we further verified that the peak shape and activation energy of the SAP of poly(4-bromostyrene) are not sensitive to temperature, nor do they vary upon confinement at the nanoscale level. These observations confirm the preliminary trends reported for other polymers. We find that one single set of parameters—meaning the activation barrier and the pre-exponential factor, respectively, linked to the enthalpic and entropic components of the process—can describe the dynamics of the SAP in both the supercooled liquid and glassy states, in bulk and thin films. These results are discussed in terms of possible molecular origins of the slow Arrhenius process in polymers.

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1D-Confinement Inhibits the Anomaly in Secondary Relaxation of a Fluorinated Polymer

Cited by 3 publications

References 33 publications

Phase Transitions in Poly(vinylidene fluoride)/Polymethylene-Based Diblock Copolymers and Blends

Phase Transitions in Poly(vinylidene fluoride)/Polymethylene-Based Diblock Copolymers and Blends

Polymer Nanocomposite Dielectrics: Understanding the Matrix/Particle Interface

Tracing the slow Arrhenius process deep in the glassy state–quantitative evaluation of the dielectric relaxation of bulk samples and thin polymer films in the temperature domain

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