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EP-4740715-A1 - AN ELECTROACTIVE POLYMER-BASED DEVICE AND METHOD FOR MANUFACTURING

EP4740715A1EP 4740715 A1EP4740715 A1EP 4740715A1EP-4740715-A1

Abstract

The present application shows an electroactive polymer, EAR, based device (10, 20) including: a dielectric layer (13, 23) arranged between two electrode layers (12, 14), the dielectric layer (13, 24) consisting of a stretchable material, the two electrode layers (12, 14) including a carbon based conductive material and a solid state oxidant material forming stretchable layers, the EAP-based device further including an additional dielectric layer (11, 15) of the stretchable material arranged on each of the two electrode layers (11, 13), and configured together with the dielectric layer (13, 23) to seal each of the two electrode layers (12, 14) therein.

Inventors

  • XU, Zihang
  • WU, KAI
  • LV, Zepeng
  • Claverie, Aurore
  • TAINE, Emmanuel
  • MORSHUIS, Peter

Assignees

  • Single Buoy Moorings Inc.

Dates

Publication Date
20260513
Application Date
20240702

Claims (17)

  1. 1 . An electroactive polymer, EAP, -based device (10, 20) comprising: a dielectric layer (13, 23) arranged between two electrode layers (12, 14), the dielectric layer (13, 23) consisting of a stretchable material, the two electrode layers (12, 14) comprising a carbon based conductive material and a solid state oxidant material forming stretchable layers, the EAP-based device further comprising an additional dielectric layer (11 , 15) of the stretchable material arranged on each of the two electrode layers (11 , 13), and configured together with the dielectric layer (13, 23) to seal each of the two electrode layers (12, 14) therein.
  2. 2. The EAP-based device according to claim 1 , further comprising an encapsulant (18) sealing the electrode layers (12, 14) and the dielectric layer (13, 23) from ambient air.
  3. 3. The EAP-based device according any one of the preceding claims, wherein the carbon based conductive material is mixed with the solid state oxidant material.
  4. 4. The EAP-based device according to any one of the preceding claims, wherein the solid-state oxidant material comprises an oxygen-containing compound.
  5. 5. The EAP-based device according to any one of the preceding claims, wherein the solid state oxidant material comprises one or more compounds selected from: a group comprising: permanganate, nitrate, dichromate, perborate, and chlorate.
  6. 6. The EAP-based device according to claim 5 or claim 5, wherein the solid state oxidant material comprises sodium or potassium as cation of the one or more compounds.
  7. 7. The EAP-based device according any one of the preceding claims, wherein the solid state oxidant material has a concentration equal to or lower than 10wt% in the electrode layer, the electrode layer having a thickness below 5 microns.
  8. 8. The EAP-based device according to any one of the preceding claims, further comprising at least one stack alternating an electrode layer (16) comprising the carbon based conductive material and the solid state oxidant material and a dielectric layer (17) of the stretchable material on at least one of the additional dielectric layers (11 , 15), the dielectric layer (17) of the stack configured together with the additional dielectric layers (11 , 15) to seal the electrode layer (16) of the stack therein.
  9. 9. The EAP-based device according to any one of the preceding claims, wherein the carbon based conductive material of the electrode layer (12, 14, 16) comprises nanoparticles of at least one of carbon black material, single-wall carbon nanotube material, multi-wall carbon nanotube material and graphene material.
  10. 10. The EAP-based device according to any one of the preceding claims, wherein the stretchable material of the dielectric layers (11 , 13, 15, 17) is selected from a group comprising silicone, rubber, thermoplastic polyurethane (TPU).
  11. 11 . The EAP-based device according to any one of the preceding claims, wherein the electrode layers (12, 14, 16) further comprise an additive, such as a silane-based coupling agent, for promoting adhesion of the electrode layer to the dielectric layers.
  12. 12. The EAP-based device according to any one of claims 2, and 3 to 11 , when dependent on claim 2 wherein the encapsulant (18) is made of a polymer material, selected from a group comprising silicone, epoxy, urethane.
  13. 13. The EAP-based device according to any one of the preceding claims, wherein the electrode layers (12, 14, 16) and the dielectric layers (11 , 13, 15, 17) are encapsulated under vacuum or under nitrogen ambient.
  14. 14. Method for manufacturing an electroactive polymer, EAP, based device (10, 20) comprising: - providing in a processing volume two or more dielectric layers (11 , 13, 15, 17) consisting of a stretchable material; - arranging (104) an electrode layer (12, 14, 16) made of a carbon based conductive material on at least one of the two or more dielectric layers (11 , 13, 15, 17) wherein the electrode layer (12, 14, 16) comprises a carbon based conductive material, - covering (104) an exposed surface of at least one of the electrode layers (12, 14, 16) with another dielectric layer made of the stretchable material, -adding (102) a solid state oxidant material to the carbon based conductive material of the electrode layers (11 , 13, 15, 17); while the electrode layers (12, 14, 16) are being arranged on the at least one of the two or more dielectric layers (11 , 13, 15, 17), the method characterized in that it further comprises: maintaining a substantially oxygen free atmosphere or vacuum in the processing volume and configuring the dielectric layers to seal one of the electrode layers therebetween.
  15. 15. Method for manufacturing a EAP-based device according to claim 13, wherein the step of arranging (104) the electrode layer on at least one of the two or more dielectric layers (11 , 13, 15, 17) comprises spraying a carbon-based dispersion solution comprising the solid state oxidant and an additive on the at least one of the dielectric layers, the additive promoting adhesion of the electrode layer to the at least one dielectric layer.
  16. 16. Use of a EAP-based device according to any one of claims 1 to 13, or manufactured according to any one of claims 13 to 14.
  17. 17. Method of self-clearing a EAP-based device according to any one of claims 1 to 12, or manufactured according to any one of claims 14 to 15, subject to dielectric breakdown comprising - releasing gaseous oxygen from the electrode layers comprising a solid state oxidant and carbon-based material, - generating carbon dioxide and/or carbon monoxide by reaction of the released gaseous oxygen with the carbon-based material of the electrodes.

Description

An electroactive polymer-based device and method for manufacturing Field of the invention The invention relates to an electroactive polymer-based device. The invention further relates to a method of manufacturing an EAP-based device, use of such a device and a method of self-clearing such a device. Background Electro-mechanical energy conversion systems using an electroactive polymer (EAP) based device are for example disclosed in WO2010/146457. Such an EAP-based device comprises a dielectric elastomer layer. On the surfaces of the dielectric elastomer layer, electrode layers are arranged. The EAP-based device can be considered as a variable capacitor of which the capacitance changes as a function of an amount of deformation exerted on a layer of EAP material. Due to an external force the electroactive polymer material can be stretched which causes that a distance between the electrode layers decreases. The distance increases again when the external force diminishes and the electro-active polymer layer relaxes. By applying electrical charges on the electrode layers at substantially the maximal deformation and removing the electrical charges at minimal deformation, energy can be harvested from the EAP-based device. Electrode layers made of metal show plastic deformation and cracking at relatively low stretch rates of the elastomer carrier layer and deteriorate strongly during a relatively low number of stretching cycles. For this reason, carbon-based electrodes which show enhanced stretching properties have emerged as candidates to manufacture EAP-based device layers. However, despite the enhanced stretching properties of the carbon-based electrodes, local defects, such as air bubbles or contamination, may be present in the dielectric layer forming small openings or thinned regions. When exposed to an electrical field, a dielectric breakdown will occur at low field strengths, causing a pinhole defect across the thickness of the dielectric layer and above all a shortcut, so that the EAP-based device is no more operational to harvest energy. Therefore the device fails at a time that is much shorter than the design lifetime It is therefore an object of the present invention to provide an EAP-based device with carbon based electrode layers having an improved lifetime and electrical performance during exposure to mechanical cycling with relatively high deformation. Summary of the invention According to a first aspect of the invention, an EAP-based device is disclosed, the EAP-based device comprising: a dielectric layer arranged between two electrode layers, the dielectric layer consisting of a stretchable material, the two electrode layers comprising a carbon based conductive material and a solid state oxidant material forming stretchable layers, the EAP-based device further comprising an additional dielectric layer of the stretchable material arranged on each of the two electrode layers, and configured together with the dielectric layer to seal each of the two electrode layers therein. The EAP-based device of the invention comprises composite electrode layers made of a strong oxidant and a carbon material which offer both stretchability and an excellent conductivity. Each dielectric layer of the EAP-based device is also stretchable and is surrounded by one electrode layer at each side, forming a stack alternating dielectric layer and electrode layer, so as to form a capacitor. Thanks to their high conductivity and stretchability, the electrodes will efficiently conduct current, and be capable of repetitive stretching together with the dielectric layers. The EAP-based device may therefore be used in a variety of flexible electronic components, such as actuators or sensors, as well as electrical equipment. When connected to power electronics the EAP- based device can be used as a variable capacitor to harvest energy. Furthermore, the electrode layers of the EAP-based device comprise solid state oxidant, which makes them capable of self-clearing. When an electrical breakdown occurs, the electrode layers comprising the oxidant will decompose and thereby will isolate the area from the current and generate the clearing of the electrode in the breakdown area: the oxygen integrated in solid status in the electrode will be vapourised by the energy delivered by the breakdown and will react with carbon material of the electrode layer to form carbon oxidated molecules. The volume of electrode layer nearing a damaged section of the dielectric layer is thereby cleared up, insulating the short-circuited section from the rest of the EAP-based device. The EAP-based device of the invention will hence quickly return to a working state. The oxygen present in the oxidant can only interact with the electrode layers at breakdown, when it is released by the energy created by the breakdown from the electrode layers themselves as otherwise the electrode layers are sealed from the ambient air by the dielectric layers. The device which c