Dielectric property of all-organic composite film composed of cobalt phthalocyanine and poly(vinylidene fluoride)

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Due to the mechanical flexibility, tunable properties and easy processing, polymer based composites, especially the electroactive polymer composites based on the poly(vinylidene fluoride), which can be applied in the sensors, transistors and the capacitors, have been widely investigated. In this paper, all-organic composite films composed of cobalt phthalocyanine and poly(vinylidene fluoride) with high dielectric permittivity are simply synthesized by solution casting on the glass. The dielectric property over the broad frequency from 1Hz to 10⁷Hz is investigated. The high dielectric permittivity 86.4(10²Hz), about 9 times of the pure poly(vinylidene fluoride), is achieved when the fraction of the cobalt phthalocyanine is 20wt% that is similar to other semiconductors reinforced polymer composites. The significant increase of the dielectric constant and the dielectric loss tangent can be explained by the threshold theory. The origin of dramatically enhancement of dielectric permittivity and dielectric loss tangent over the low frequency is the Maxwell-Wagner-Sillars polarization. The results show that the dielectric property is very sensitive to the fraction of cobalt phthalocyanine. Additionally, when the fraction of the cobalt phthalocyanine was 10wt%, the dielectric permittivity and the conductivity of composite films are 17.1 and 1.1×10^-6s/cm respectively which indicated that it is potentially applied in the capacitors.