Composition based on electroactive terpolymer
The invention relates to a composition comprising at least one electroactive fluorinated terpolymer, and at least one second polymer compatible with the electroactive fluorinated terpolymer and having a glass transition temperature lower than that of the electroactive fluorinated terpolymer. The invention also relates to a method for producing said composition, and to a device such as an actuator comprising a substrate and a film of the above-mentioned composition.
1. A composition comprising:
at least one electroactive fluoroterpolymer, and
at least one second polymer compatible with the electroactive fluoroterpolymer and exhibiting a glass transition temperature lower than that of the electroactive fluoroterpolymer, wherein the second polymer is a polyester.
2. The composition as claimed in claim 1 , in which the second polymer exhibits a glass transition temperature lower by at least 5° C. than that of the electroactive fluoroterpolymer.
3. The composition as claimed in claim 1 , in which the glass transition temperature of the electroactive fluoroterpolymer has a value of −50° C. to +10° C., and/or the glass transition temperature of the second polymer has a value of −100° C. to 0° C.
4. The composition as claimed in claim 1 , in which the electroactive fluoroterpolymer is a terpolymer of vinylidene fluoride, of trifluoroethylene and of a third monomer.
5. The composition as claimed in claim 4 , in which the third monomer is 1-chloro-1-fluoroethylene or chlorotrifluoroethylene.
6. The composition as claimed in claim 1 , in which the electroactive fluoroterpolymer and the second polymer are present in a ratio by weight of 50:50 to 99:1.
7. The composition as claimed in claim 1 , comprising at least one solvent that is tetrahydrofuran, methyl ethyl ketone, dimethylformamide, dimethylacetamide, tetramethylurea, dimethyl sulfoxide, trimethyl phosphate, N-methyl-2-pyrrolidone, acetone, methyl isobutyl ketone, glycol ethers, glycol ether esters, n-butyl acetate, cyclohexanone, diacetone alcohol, diisobutyl ketone, ethyl acetoacetate, butyrolactone, isophorone, triethyl phosphate, carbitol acetate, propylene carbonate or glyceryl triacetate.
8. The composition as claimed in claim 1 , in which:
the electroactive fluoroterpolymer exhibits a molecular weight of 200 000 to 1 500 000 and/or
the second polymer exhibits a molecular weight of 500 to 700 000.
9. The composition as claimed in claim 1 , also comprising a fluorocopolymer.
10. The composition according to claim 9 , wherein the fluorocopolymer is a ferroelectric fluorocopolymer that is a copolymer of vinylidene fluoride and of trifluoroethylene, of vinylidene fluoride and of chlorotrifluoroethylene, of vinylidene fluoride and of tetrafluoroethylene, or of vinylidene fluoride and hexafluoropropylene.
11. The composition as claimed in claim 1 , in which the electroactive fluoroterpolymer is a relaxor terpolymer.
12. The composition according to claim 1 , wherein the polyester is a polyadipate, polyglutarate or polysebacate.
13. A process for the manufacture of a composition as claimed in claim 1 , comprising a stage of mixing the electroactive fluoroterpolymer with the second polymer.
14. The manufacturing process as claimed in claim 13 , in which the mixing is carried out in a solvent that is tetrahydrofuran, methyl ethyl ketone, dimethylformamide, dimethylacetamide, tetramethylurea, dimethyl sulfoxide, trimethyl phosphate, N-methyl-2-pyrrolidone, acetone, methyl isobutyl ketone, glycol ethers, glycol ether esters, n-butyl acetate, cyclohexanone, diacetone alcohol, diisobutyl ketone, ethyl acetoacetate, butyrolactone, isophorone, triethyl phosphate, carbitol acetate, propylene carbonate or glyceryl triacetate, by dissolving the electroactive fluoroterpolymer and then the second polymer in the solvent.
15. A device comprising a substrate and a film of the composition as claimed in claim 1 deposited on the substrate.
16. The device as claimed in claim 15 , additionally comprising electrodes on either side of the film, said device being an actuator.
17. A process for the manufacture of the device as claimed in claim 15 , comprising a stage of deposition of the film on the substrate.
18. The process for the manufacture of the device as claimed in claim 17 , in which the stage of the deposition is a stage of coating or printing the composition on the substrate.
19. The process for the manufacture of the device as claimed in claim 17 , comprising an additional stage of deposition of electrodes by evaporation or sputtering of metal or indium tin oxide, deposition of a layer of conductive polymer, or deposition of conductive ink based on silver, on silver nanowires, or on graphene.