Polyvinylidene fluoride composite oriented dielectric film with high beta-crystal content and preparation method of dielectric film

Abstract

The invention discloses a polyvinylidene fluoride composite oriented dielectric film with high beta-crystal content and a preparation method of the dielectric film. The polyvinylidene fluoride composite oriented dielectric film is a blend, and the blend contains polyvinylidene fluoride (PVDF) and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6). The preparation method comprises the following steps: mixing PVDF and BMIMPF6 according to a mass ratio of 100:(0.5-30), and adding N, N-dimethyl formamide to cause the concentration of the PVDF solution to be 1-20wt%; magnetically stirring at the temperature of 40-60 DEG C for 5-24 hours to prepare a PVDF / BMIMPF6 solution with a certain mass ratio; performing film forming on a casting solution on a constant temperature heating stage by adopting a spin-coating method, thereby preparing the highly oriented PVDF film by using a uniaxial stretching device after the solvent is completely volatilized. The oriented PVDF film has anisotropism and high beta-crystal content, and the dielectric constant is improved. Meanwhile, the contact angle is reduced along with the increase of the content of ionic liquid, and the hydrophilcity is improved. The prepared film has excellent piezoelectric and dielectric properties, is simple in preparation method and process flow and favorable for industrial production and has wide market application prospects.

Description

technical field [0001] The invention relates to the field of polyvinylidene fluoride processing, in particular to a high-β-phase polyvinylidene fluoride oriented film with high dielectric constant, and in particular to a polyvinylidene fluoride compound with high β-crystal content obtained by utilizing ionic liquid and uniaxial stretching Oriented dielectric film and its preparation method. Background technique [0002] In recent years, the scale of the electronic product market has continued to expand, and thin film capacitors with high energy storage and ultra-miniaturization have become a research hotspot. PVDF film has good flexibility, high mechanical strength, good chemical and oily corrosion resistance, and high dielectric constant. However, the dielectric constants of the current industrialized organic dielectric materials are relatively low, which hinders the further development of this type of film capacitor. The dielectric constant of PVDF is 8-11, which is abou...

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Problems solved by technology

At present, the content of β-phase crystals in PVDF films prepared by these methods is low, which is not conducive to unified standardized production and industrial application.

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