Transducer including an elastomer
A transducer includes a high-resistance layer that includes an elastomer and has a volume resistivity of 10 12 Ω·cm or more, a pair of electrodes that are arranged on both a front side and a back side of the high-resistance layer and include a binder and a conductive material, and a medium-resistance layer that is interposed between the electrode and the high-resistance layer on at least one of the front side and the back side of the high-resistance layer, includes an elastomer, and has a volume resistivity that is smaller than the volume resistivity of the high-resistance layer by two or more digits. In the transducer, the medium-resistance layer is interposed between at least one electrode and the high-resistance layer to take advantage of the resistance to dielectric breakdown originally possessed by the high-resistance layer, thereby obtaining a larger force by applying a higher voltage.
1. A transducer, comprising:
a high-resistance layer that includes an elastomer and has a volume resistivity of 10 12 Ω·cm or more;
a pair of electrodes that are arranged on both a front side and a back side of the high-resistance layer and include a binder and a conductive material; and
a medium-resistance layer that is interposed between one of the electrodes and the high-resistance layer on at least one of the front side and the back side of the high-resistance layer, has a volume resistivity that is smaller than the volume resistivity of the high-resistance layer by two or more digits,
wherein the medium-resistance layer includes: an elastomer, ion-immobilized particles in which first ionic components are immobilized to metallic oxide particles, and second ionic components having electric charges opposite to electric charges of the first ionic components,
the ion-immobilized particles are chemically bonded to the elastomer, and the polarity of the electric charges of the first ionic components is same as the polarity of the electrode adjacently provided.
2. The transducer according to claim 1 , wherein the medium-resistance layer is arranged on both the front side and the back side of the high-resistance layer.
3. The transducer according to claim 1 , wherein the thickness ratio of the high-resistance layer with respect to the entire thickness of the high-resistance layer and the medium-resistance layer is 0.1 or more and 0.75 or less.
4. The transducer according to claim 1 , wherein the thickness of the high-resistance layer is between 5 μm and 50 μm.
5. The transducer according to claim 1 wherein the median diameter of the metallic oxide particles is between 5 nm and 100 nm.
6. The transducer according to claim 1 , wherein the ion-immobilized particles are synthesized by causing a reactive ionic liquid containing the first ionic components before immobilization and the second ionic components to react with the metallic oxide particles obtained by hydrolytic reaction of an organometallic compound.
7. The transducer according to claim 6 , wherein the first ionic components contained in the reactive ionic liquid include an alkoxysilyl group, and the first ionic components are immobilized by reaction between the alkoxysilyl group and a hydroxy group of the metallic oxide particles.
8. The transducer according to claim 1 , wherein the ion-immobilized particles include a hydroxy group, and the elastomer in the medium-resistance layer includes one or more functional groups selected from a carboxy group, an amino group and an epoxy group.
9. The transducer according to claim 1 , wherein the metallic oxide particles contain one or more elements selected from titanium, zirconium, and silicon.
10. The transducer according to claim 1 , wherein the content of the ion-immobilized particles in the medium-resistance layer is between 1 part by mass and 10 parts by mass with respect to 100 parts by mass of the elastomer.