Evolution of morphology, ferroelectric, and mechanical properties in poly(vinylidene fluoride)–poly(vinylidene fluoride‐trifluoroethylene) blends

Abstract

Considering the complementary properties of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride‐trifluoroethylene) [P(VDF‐TrFE)], it appears that their blends have the potential to be promising candidates for device applications. We report the evolution of morphology, ferroelectric, and mechanical properties (modulus and hardness) and their dependence on preparation temperature for PVDF–P(VDF‐TrFE) blends. From ferroelectric hysteresis measurements it was found that P(VDF‐TrFE) rich blends treated at higher temperature show significant values of remanent polarization. Remanent polarization values show a fourfold increase in these P(VDF‐TrFE) rich blends treated at higher temperature. Interestingly, blends prepared from high temperature showed greater value of remanent polarization even though they were found to consist of smaller amount of electroactive phase as compared to their low temperature treated counterpart. Nanoindentation experiments revealed that high temperature treatment improves the modulus of blends by at least 100%. This report attempts to tie these findings to the morphology and crystallinity of these blends. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45955.

Influence of Microstructure on the Nanomechanical Properties of Polymorphic Phases of Poly(vinylidene fluoride)

“…PVDF is one promising functional polymer extensively used in applications ranging from energy transductions , to filtration membranes , and nonvolatile FE-RAMs , to space mirrors . PVDF is widely studied for its outstanding electroactive properties, chemical inertness, and high dielectric constant compared with other polymers. , The physical properties of PVDF and content of different polymorphic phases can be controlled by varying synthesis conditions. , From the above discussion, it becomes apparent that electrical properties and polymorphism in PVDF have been studied quite extensively. The Mechanical properties of materials play a pivotal role in determining the function and realizing smooth operation of devices.…”

“…The mechanical properties of materials are strongly correlated with the underlying microstructure. , For example, in our previous study, we found that the hardness of PVDF-P­(VDF-TrFE) blends is intimately linked to their morphology. The hardness values show a marked decline when the blend morphology changes into fiber-shaped crystals . Therefore, understanding crystallization in polymers becomes imperative for tailoring their mechanical properties.…”

“…13,14 The physical properties of PVDF and content of different polymorphic phases can be controlled by varying synthesis conditions. 15,16 From the above discussion, it becomes apparent that electrical properties and polymorphism in PVDF have been studied quite extensively. The Mechanical properties of materials play a pivotal role in determining the function and realizing smooth operation of devices.…”

“…The hardness values show a marked decline when the blend morphology changes into fiber-shaped crystals. 16 Therefore, understanding crystallization in polymers becomes imperative for tailoring their mechanical properties.…”

“…Recently, we reported on the enhancement of the mechanical properties of drop-casted PVDF-P(VDF-TrFE) blend films by increasing the crystallization temperature. 16 Oliveira et al performed nano-and microindentation tests on PVDF and found that in low-load regimes (∼100−5000 μN/s load rates) the modulus values decrease with loading rates, while at higher loads the modulus values tend to increase with increasing loading rates. 25 According to the authors, during nanoscale loading, small volume deformations and local heating effects lead to a decrease in viscosity along with a subsequent drop in elastic modulus.…”