Revolutionary all-organic composite ferroelectric-relaxor P(VDF-TrFE-CFE) for low electric field actuators

J.-F. Capsal (1) , J. Galineau (1) , P.-J. Cottinet (1) , M. Lallart (1) , Minh-Quyen Le (1)

1 LGEF - Laboratoire de Génie Electrique et Ferroélectricité

The various types of natural muscle are incredible material systems that enable the production of large deformations by repetitive molecular motions. Electroactive Polymer technologies are being developed that produce similar strains and higher stresses using electrostatic forces, electrostriction, ion insertion, and molecular conformational changes. Materials used include elastomers, conducting polymers, ionically conducting polymers, and carbon nanotubes. These polymers reach large strain response to an electric field, making them good candidates as low frequency active actuators. Fluorinated terpolymer P(VDF-TrFE-CFE) is a semi-crystalline polymer which shows the highest level of conversion from electrical to mechanical energy thanks to its high dielectric permittivity (εΓ ∼ 50) and high mechanical modulus. However, large electrical field are required (E > 100V/μm) to reach sufficient strain levels (> 2%). In this work, fluorinated terpolymer P(VDF-TrFE-CFE) was doped with (2-ethylhexyl) phthalate (DEHP). Such modified terpolymer leads to 28-fold increase of the electrostrictive strain under low applied electric field and 233-fold increase of the mechanical energy compared to the neat polymer. This simple chemical doping allows the use of the exceptional properties of the terpolymer at an electric field 5.5 times lower than that of the pure terpolymer. In addition, the proposed structure in this paper is relatively cheap, industrially used and could potentially break a technological lock as the performance recorded at low electric field are greater than any conventional electroactive polymer.

Mots clés: Actuators; Conducting polymers; Elasticity; Permittivity; Strain; Strength of materials; Structural design; Yarn; Conformational change; Electro-active polymers; Electrostrictive strain; Ferroelectric relaxors; Mechanical energies; Mechanical modulus; Properties of the terpolymers; Semi-crystalline polymer; Electric fields

Domaines: Sciences de l'ingénieur [physics]

J.-F. Capsal, J. Galineau, P.-J. Cottinet, M. Lallart, Minh-Quyen Le. Revolutionary all-organic composite ferroelectric-relaxor P(VDF-TrFE-CFE) for low electric field actuators. Composites and Advanced Materials, 2014, Orlando, United States. ⟨hal-01770269⟩