Complex Dynamics of a Fluorinated Vinylidene Cyanide Copolymer Highlighted by Dielectric Relaxation Spectroscopy

Abstract

The complex dynamics of a nearly alternating copolymer of vinylidene cyanide (1,1-dicyanoethylene, VCN) with 2,2,2-trifluoroethyl methacrylate (TFEMA), including two alpha-relaxations with diverging time scale in the glass transition temperature range, was thoroughly characterized by dielectric\ud spectroscopy over wide temperature and frequency ranges and analyzed in the frame of the Ngai’s coupling model. The dielectric relaxation strength as well as the glass transition temperature, the temperature dependence of the α-relaxation time, and the corresponding distribution of relaxation times were all larger than those of a reference TFEMA homopolymer, as expected from the introduction of the stiffening VCN units all along the macromolecular chain. The effect of casting\ud solvent and applied poling electric field on the copolymer dielectric strength suggests the onset of local orientational order involving the strong dipoles in the VCN units, a requirement for piezo- and pyroelectricity in amorphous polymer

Preparation and dielectric properties of poly(acrylonitrile-co-2,2,2-trifluoroethyl methacrylate) materialsviaradical emulsion copolymerization

“…This result is in good agreement with the data reported in the literature. 35,38 Electrode polarization is negligible, as evidenced by the low values of at T> T g .…”

“…More recently, results of the dielectric characterization were reported. 38 Compared to MATRIF homopolymer as a reference, the introduction of polar VCN units results in an increase of both dielectric constant and glass transition temperature. This behaviour is required for bringing piezo-and pyroelectricity in amorphous polymers.…”

Reversible Phase Transition with Ultralarge Dielectric Relaxation Behaviors in Succinimide Lithium(I) Hybrids

“…Research on reversible phase transitions and their dielectric, ferroelectric, and nonlinear optical properties have become one of the hotspots in the past decade, because their special dielectric and polarization properties in the solid–solid state phase transitions have been widely applied on high permittivity capacitors, dielectric switches, ferroelectrics, pyroelectrics, electrical insulating material, etc. − …”

Effect of clay on the dielectric properties of novel fluorinated methacrylate nanocomposites

“…The experimental data can be split into two dipolar relaxation processes as well as dc‐conductivity. The dipolar relaxation process detected at low temperature can be attributed to β relaxation resulted from the ester side‐group rotation around its bond with the backbone chain . Indeed, unlike aromatic polyesters and polycarbonates in which dipolar groups are rigidly attached to the main‐chain, the PMATRIF have an added dipole‐component in the ester side‐groups flexibly attached to the main chain.…”

“…As an important class of such materials, we deal in our work with poly(2,2,2‐trifluoroethyl methacrylate) (PMATRIF) which has excellent water‐repellent capacity, good gas permeability for oxygen, lower water‐absorption, and stain resistance . The dielectric properties of polymers and copolymers based on MATRIF with cyanocomonomers were reported and the relationship structure‐dielectric constant has been studied in detail . However these amorphous fluoroalkymethacrylate polymers that is, PMATRIF, exhibit lower dielectric constant which limits the development of high energy‐storage density polymer capacitors.…”