Actuation efficiency of polyvinylidene fluoride-based co- and ter-polymers

• Published in: Polymer (Guilford) Vol. 156; pp. 270 - 275
• Main Authors: Lheritier, Pierre, Noel, Sébastien, Vaxelaire, Nicolas, Domingues Dos Santos, Fabrice, Defay, Emmanuel
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 07.11.2018; Elsevier BV
• Subjects: Actuation; Chlorotrifluoroethylene; Copolymers; Coupling; Electric fields; Electromechanical coupling; Ferroelectric materials; Ferroelectricity; Fluorides; Polymers; Polyvinylidene fluorides; Relaxors; Stiffness; Ter-polymer; Thin films; Vinylidene fluoride; Thin films; Electromechanical coupling; Ter-polymer
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2018.10.003

Poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) ter-polymers reach strain up to 4% with the application of an electric field. This is several times larger than PVDF-TrFE co-polymers. However this large strain comes with reduced stiffness, which is detrimental to ter-polymers integration in heterogeneous structures. Here we compare the actuation capabilities of cantilevers with P(VDF-TrFE-CTFE) and P(VDF-TrFE) as active layer. Our ter-polymers exhibit CTFE composition ranging from 0 to 9.7%. We compared the electrical and mechanical displacements as well as the electromechanical coupling of these devices. We found that ter-polymer devices with CTFE ratio below 8% are ferroelectric whereas they become relaxor beyond 8% of CTFE. The maximum deflections of all cantilevers at high electric field are comparable, though slightly larger for the ter-polymer with 5% CTFE. The main finding of this paper concerns the effective electromechanical coupling of ter-polymers that is at best only half of the co-polymer one. [Display omitted] •Below 8% CTFE, P(VDF-TrFE-CTFE) terpolymers are still ferroelectric.•Terpolymers with a CTFE content around 5% possess the best performances at high electrical fields.•The electromechanical coupling of terpolymer based actuator is half that of copolymer based ones.