Calculations of the elastic compliance and piezoelectric constants of poly(vinylidene fluoride) and poly(vinylidene fluoride-trifluoroethylene) crystals

• Published in: Ferroelectrics Vol. 205; no. 1; pp. 133 - 145
• Main Authors: Kavarnos, G. J., Robinson, H. C., Holman, R. W.
• Format: Journal Article
• Language: English
• Published: London Taylor & Francis Group 01-01-1998; Taylor and Francis
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electrical, magnetic and optical properties; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Physics; Piezoelectric and electrostrictive constants; Piezoelectricity and electromechanical effects; Properties and characterization; Elastic modulus; Polarization; Hartree-Fock calculations; Total energy; Compliance; Force field; Minimization; Organic polymers; Experimental study; Coulomb interaction; Compressive stress; Vinylidene fluoride copolymer; Vinylidene fluoride polymer; Molecular model; Piezoelectricity; Chemical composition; Stiffness; Lennard Jones model; Permittivity; Trifluoroethylene copolymer
• ISSN: 0015-0193; 1563-5112
• DOI: 10.1080/00150199808228393

We present calculated compliance and piezoelectric constants for polyvinylidene fluoride (PVDF) and its copolymer with trifluoroethylene P(VDF/TrFE). The constants were derived by minimizing the energy of the unit cell under various states of stress, using a modified molecular mechanics force field. The model was first validated against experimental data and theoretical calculations for the properties of PVDF. The behavior of the compliance and piezoelectric constants of P(VDF/TrFE) are examined as a function of the molecular percentage of VDF. It was found that an optimum value for the dielectric constant d
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of P(VDF-TrFE) exists between 55 and 65 mol % VDF.