Local variation of the dielectric properties of poly(vinylidene fluoride) during the α- to β-phase transformation

Effects of processing methods on dielectric properties of BaTiO3/poly(vinylidene fluoride) nanocomposites

“…In this current study, PVDF was chosen as a polymer matrix due to its high e 0 value and electroactive response, including piezoelectric, pyroelectric and ferroelectric effects [27,30]. BaTiO 3 with particle size of about 100 nm was used as a filler in PVDF to study the specific characteristic distribution when prepared by different methods.…”

“…The relationship between the ADP behavior and microstructural evolution has also never been reported. Investigation of the ADP behavior and the formation of agglomerated filler particles can provide an important underlying mechanism for improving the dielectric properties as well as other important properties of PVDF based on electroactive response such as piezoelectric, pyroelectric and ferroelectric responses [27]. These properties can be used in many applications such as in energy generation and storage [1,9,10,28], sensors [29], and etc.…”

Influence of MWCNTs on β-Phase PVDF and Triboelectric Properties

“…The -phase of PVDF with the all-trans conformation of fluorine atoms leads to high values of electric polarization to the unit cell [7,8]. Generally, the -phase of the crystalline structure of PVDF can be enhanced by either mechanical deformation in the uniaxial or biaxial directions or application of a highly intense electric field to the PVDF film above its glass transition temperature [9][10][11]. As a new energy harvesting technology, contact-electrification based energy conversion devices, that is, triboelectric nanogenerators, have been developed in such a way that they can achieve high efficiency for producing large output power as well as easy fabrication [12][13][14].…”

Imaging the Effects of Annealing on the Polymorphic Phases of Poly(vinylidene fluoride)

“…1 Current interest in PVDF involves understanding the relationship between polymorphic composition and crystallization conditions, [2][3][4] which ultimately influence the dielectric properties of the polymer. 5 The three most common phases of PVDF (Figure 1) are the non-polar α-phase (cis-trans conformation), polar and ferroelectric β-phase (all trans conformation), and γ-phase (kinked all trans conformation). Interconversion between these phases is induced through electric-field poling 6 , annealing 2 , or mechanical straining (i.e., "stretching" or "drawing") [7][8] .…”

“…By employing the solvatochromic organic dye nile red (NR), they were able to monitor the effect of "stretching" a PVDF film, which induced a transition from α-to β-phase, with the observed shift in the NR emission to longer wavelengths consistent with increased polarity of the β-phase. 5 In this manuscript, we explore the effect of annealing on the dielectric properties of PVDF using our developed quasi-single molecule (quasi-SM) technique that measures the spatial variation in the dielectric constant (ε) in polymer films. 9 By employing the solvatochromic properties of NR embedded in non-annealed and annealed PVDF films, we are able to spatially map the dielectric environments present within a polymer before and after annealing.…”