Nucleation Effect of the Chemical Structure of Alkylammonium Salt on the Crystallization Behavior of Poly(Vinylidene Fluoride)

Tatsuaki Miyashita,Hiromu Saito,Yaming Wang

doi:10.1155/2022/5807491

Tatsuaki Miyashita, Hiromu Saito + Show 1 more

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https://doi.org/10.1155/2022/5807491

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Abstract

We investigated the effect of the chemical structure of alkylammonium salt on the crystallization behavior of poly(vinylidene fluoride) (PVDF) by DSC, optical microscopy, light scattering, and FT-IR. The nonisothermal and isothermal crystallizations of PVDF were accelerated by adding alkylammonium salt consisting of short alkyl chains and small anion species, and the spherulite size and the ordering in the spherulite became smaller due to the nucleation agent effect. The FT-IR spectra revealed that electroactive γ-phase was preferentially formed by adding alkylammonium salts though the accelerated crystallization was suppressed due to the steric hindrance effect by the long alkyl chain and large anion species. On the other hand, the formation of the γ-phase was suppressed when the dispersion of the salt in the PVDF matrix was poor due to the high melting temperature.

Highlights

Poly(vinylidene fluoride) (PVDF) is widely used for industrial applications such as chemical valves, membranes for water treatment, and sensors due to its excellent chemical resistance, weathering resistance, and ferroelectricity [1, 2]
It is known that polar β- or c-phase can be effectively induced by adding inorganic filler [18] such as nanoclay [19,20,21], graphene oxide [22], and carbon nanotube [23,24,25,26,27]. e polar phase can be induced by adding ionic salts [18] such as ionic liquids [28], KBr [29], cetyltrimethylammonium bromide (CTAB) [30,31,32], ionic fluorinated surfactant [33], onium salt [34, 35]. e induction of the polar phase is explained by ion-dipole interactions between ionic salts and PVDF chains
We investigated the crystallization kinetics and crystalline structure of PVDF added with a series of alkylammonium salt consisting of various lengths of alkyl chain and various sizes of anion species. e crystallization behavior was discussed by the results of DSC and light scattering measurements for crystallization kinetics, polarized optical microscopic observation for the spherulite structure, and FT-IR for the crystalline phase

Summary

Introduction

Poly(vinylidene fluoride) (PVDF) is widely used for industrial applications such as chemical valves, membranes for water treatment, and sensors due to its excellent chemical resistance, weathering resistance, and ferroelectricity [1, 2].

Results

Conclusion