DC conduction mechanism and dielectric properties of Poly (methyl methacrylate)/Poly (vinyl acetate) blends doped and undoped with malachite green

• Published in: Physica. B, Condensed matter Vol. 408; pp. 140 - 150
• Main Authors: Abd-El Kader, F.H., Osman, W.H., Hafez, R.S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.01.2013; Elsevier
• Subjects: Applied sciences; Blends; DC conduction; Dielectric spectroscopy; Direct current; Electrical conduction; Electrical, magnetic and optical properties; Exact sciences and technology; I–V characteristic; Malachite green; Mathematical models; Organic polymers; Physicochemistry of polymers; Polymer blend; Polymer blends; Polymethyl methacrylates; Properties and characterization; Schottky–Rishardson mechanism; Vinyl acetate; Polymer blend; Dielectric spectroscopy; DC conduction; Schottky–Rishardson mechanism; I–V characteristic; Malachite green; Dielectric loss; Schottky-Rishardson mechanism; Electrical conductivity; Polymer blends; Voltage current curve; Organic dye; Doping; Methyl methacrylate polymer; Thin film; I-V characteristic; Space charge limited conduction; Vinyl acetate polymer; Permittivity; Activation energy; Dipole moment
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2012.09.027

Cast thin films of Poly (methyl methacrylate)/Poly (vinyl acetate) blends of different concentrations undoped and doped with malachite green have been prepared and subjected to both dc electrical conduction and dielectric spectroscopy measurements. The analysis of dc electrical conduction data showed that the space charge limited current mechanism has been dominant for Poly (vinyl acetate) while Schottky–Richardson conduction mechanism prevailed for the Poly (methyl methacrylate) and blended samples. The values of field lowering constant β and the thermal activation energy ΔE involved in the dc conduction were reported, which provide another support for the suggested Schottky–Richardson mechanism. The increase in current for the blend sample doped with malachite green has been attributed to the formation of charge transfer complexes inside the polyblend matrix. The dielectric constant as a function of temperature for all samples have been calculated which are affected by the composition ratio and the addition of dye. The relaxation peak that appeared in the dielectric loss curve at 347K for the doped blend sample is related to local dipoles that are present in the dye material. The obtained relaxation process spectra present in the investigated samples were analyzed with the well-known model of Havriliak–Negami.