MULTILAYER STRUCTURE, POLYMER ACTUATOR ELEMENT, SENSOR ELEMENT, AND DEVICE
A multilayer structure includes an electrolyte layer and electrode layers each of which is placed on a corresponding one of two principal surfaces of the electrolyte layer. The electrolyte layer includes a mixed ionic liquid containing a plurality of ionic liquids and a base polymer for electrolytes. The electrode layers both include a base polymer, a carbon material, and the mixed ionic liquid. The melting point Tmm of the mixed ionic liquid is lower than the melting point Tm1 of a first ionic liquid which has the lowest melting point among a plurality of the ionic liquids.
1 . A multilayer structure comprising:
an electrolyte layer having two main surfaces, the electrolyte layer comprising:
a first base polymer for electrolytes; and
a first ionic liquid mixture containing a plurality of ionic liquids; and
a pair of electrode layers each disposed on respective one of the two main surfaces of the electrolyte layer, each of the electrode layers comprising:
a second base polymer;
a carbon material; and
a second ionic liquid mixture which is the same as the first ionic liquid mixture,
wherein the first ionic liquid mixture has a melting point Tmm lower than a first melting point Tm1 of a first ionic liquid which has a lowest melting point among the plurality of ionic liquids.
2 . The multilayer structure according to claim 1 , wherein the melting point Tmm of the first ionic liquid mixture and the first melting point Tm1 of the first ionic liquid satisfy the following inequality:
Tmm 1≤ Tmm≤Tmm 1+( Tm 1− Tmm 1)/2
where Tmm1 is a lowest melting point of the first ionic liquid mixture obtained by varying respective blending amounts of the plurality of ionic liquids forming the first ionic liquid mixture.
3 . The multilayer structure according to claim 2 , wherein the first ionic liquid mixture contains multiple types of cations.
4 . The multilayer structure according to claim 3 , wherein the first ionic liquid mixture contains multiple types of imidazolium cations.
5 . The multilayer structure according to claim 2 , wherein the first ionic liquid mixture contains triflate anions.
6 . The multilayer structure according to claim 5 , wherein the first ionic liquid mixture contains 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI-TfO) and 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMI-TfO), and a ratio of a weight of 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMI-TfO) to a weight of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI-TfO) contained in the first ionic liquid mixture is 1.5:1 to 4:1.
7 . The multilayer structure according to claim 2 , wherein a ratio of a weight of the first ionic liquid mixture to a weight of the carbon material is 0.5:1 to 3:1.
8 . A polymer actuator element comprising the multilayer structure according to claim 3 .
9 . A polymer actuator element comprising the multilayer structure according to claim 5 .
10 . A polymer actuator element comprising the multilayer structure according to claim 7 .
11 . A device comprising the polymer actuator element according to claim 8 as a movable portion.
12 . A device comprising the polymer actuator element according to claim 9 as a movable portion.
13 . A sensor element comprising the multilayer structure according to claim 3 .
14 . A sensor element comprising the multilayer structure according to claim 5 .
15 . A device comprising the sensor element according to claim 13 as a measuring portion.
16 . A device comprising the sensor element according to claim 14 as a measuring portion.
17 . A device comprising the multilayer structure according to claim 3 , the multilayer structure being capable of functioning as an actuator element and functioning as a sensor element.
18 . A device comprising the multilayer structure according to claim 5 , the multilayer structure being capable of functioning as an actuator element and functioning as a sensor element.