Bio-electrode, and method for manufacturing the same
The present invention is a bio-electrode including: a substrate having anti-reflective structure for light on at least one side; and (A) an electro-conductive layer having electro-conductive wiring on the opposite side from the side having the anti-reflective structure of the substrate. This provides: a bio-electrode that allows thin, highly transparent, highly sensitive to biological signals, excellent in biocompatibility, light-weight, manufacturable at low cost, capable of preventing significant reduction in sensitivity to biological signals even when attached on the skin for a long time and when wetted with water or dried, and comfortable without itching, reddening, nor rash of the skin.
1 . A bio-electrode comprising:
a substrate having an anti-reflective structure for light on at least one side;
(A) an electro-conductive layer having an electro-conductive wiring on the opposite side from the side having the anti-reflective structure of the substrate; and
(B) an ion polymer containing layer on the electro-conductive layer (A).
2 . The bio-electrode according to claim 1 , wherein the anti-reflective structure for light is based on a moth-eye structure.
3 . The bio-electrode according to claim 2 , wherein the moth-eye structure has a pitch of 1000 nm or less and a depth of 10 nm or more.
4 . The bio-electrode according to claim 1 , wherein the electro-conductive wiring has a width of 200 μm or less, and a laminate film, being a combination of the layer (A) and the layer (B), has a visible light transmittance of 50% or more.
5 . The bio-electrode according to claim 4 , wherein the electro-conductive wiring having a width of 200 μm or less and is: a printed pattern using an electro-conductive paste comprising a particle of gold, silver, copper, or nickel; or a fusion layer of metal nanowires comprising gold, silver, copper, nickel, or alloy thereof.
6 . The bio-electrode according to claim 1 , wherein the ion polymer containing layer comprises a polymer comprising a repeating unit-a having at least one selected from the group consisting of fluorosulfonic acid, fluorosulfonimide, and N-carbonyl-fluorosulfonamide, and having the weight-average molecular weight in a range of 1,000 to 500,000.
7 . The bio-electrode according to claim 6 , wherein the repeating unit-a has a partial structure shown by any of the following general formulae (1)-1 to (1)-4,
wherein Rf 1 and Rf 2 each represent a hydrogen atom, a fluorine atom, an oxygen atom, a methyl group, or a trifluoromethyl group, provided that when Rf 1 and Rf 2 represent an oxygen atom, the single oxygen atom represented by Rf 1 and Rf 2 bonds to a single carbon atom to form a carbonyl group; Rf 5 and Rf 4 each represent a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of Rf 1 to Rf 4 is a fluorine atom or a trifluoromethyl group; Rf 5 , Rf 6 , and Rf 7 each represent a fluorine atom, a trifluoromethyl group, a linear or branched alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and have at least one fluorine atom or trifluoromethyl group; and M + represents an ion selected from the group consisting of an ammonium ion, a sodium ion, and a potassium ion; “m” represents an integer of 1 to 4.
8 . The bio-electrode according to claim 7 , wherein the repeating unit-a comprises at least one selected from the group consisting of repeating units-A1 to -A7 shown by the following general formulae (2),
wherein, R 1 , R 3 , R 5 , R 8 , R 10 , R 11 , and R 13 each independently represent a hydrogen atom or a methyl group; R 2 , R 4 , R 6 , R 9 , R 12 , and R 14 each independently represent a single bond or a linear, branched, or cyclic hydrocarbon group having 1 to 13 carbon atoms, the hydrocarbon group optionally having either or both of an ester group and an ether group; R 7 represents a linear or branched alkylene group having 1 to 4 carbon atoms, and one or two hydrogen atoms in R 7 are optionally substituted with a fluorine atom; X 1 , X 2 , X 3 , X 4 , X 6 , and X 7 each independently represent any of a single bond, a phenylene group, a naphthylene group, an ether group, an ester group, and an amide group; X 5 represents any of a single bond, an ether group, and an ester group; Y represents an oxygen atom or a —NR 19 — group; R 19 represents any of a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, and phenyl group, optionally comprise one or more group selected from the group consisting of ether group, carbonyl group, ester group, and amide group; and Y forms a ring together with R 4 ; Rf 1 ′ and Rf 5 ′ each represent a fluorine atom, a trifluoromethyl group, or a linear or branched alkyl group having 1 to 4 carbon atoms, and have at least one fluorine atom; “m” represents an integer of 1 to 4; a1, a2, a3, a4, a5, a6, and a7 satisfy 0≤a1≤1.0, 0≤a2≤1.0, 0≤a3≤1.0, 0≤a4≤1.0, 0≤a5≤1.0, 0≤a6≤1.0, 0≤a7≤1.0, and 0<a1+a2+a3+a4+a5+a6+a7≤1.0; and M + represents an ion selected from the group consisting of an ammonium ion, a sodium ion, and a potassium ion.
9 . The bio-electrode according to claim 8 , wherein the repeating unit-a comprises an ammonium ion shown by the following general formula (3) as an ammonium ion for forming an ammonium salt,
wherein, R 101d , R 101e , R 101f , and R 101g each represent a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 15 carbon atoms, a linear, branched, or cyclic alkenyl group or alkynyl group having 2 to 12 carbon atoms, or an aromatic group having 4 to 20 carbon atoms, and optionally have one or more selected from the group consisting of an ether group, a carbonyl group, an ester group, a hydroxy group, a carboxy group, an amino group, a nitro group, a sulfonyl group, a sulfinyl group, a halogen atom, and a sulfur atom; and R 101d and R 101e , or R 101d , R 101e , and R 101f , are optionally bonded to each other together with a nitrogen atom bonded therewith to form a ring in which R 101d and R 101e , or R 101d , R 101e , and R 101f , represent an alkylene group having 3 to 10 carbon atoms, or to form a heteroaromatic ring having the nitrogen atom in the general formula (3) within the ring.
10 . The bio-electrode according to claim 1 , further comprising one or more resin (C) selected from the group consisting of (meth)acrylate resin, (meth)acrylamide resin, urethane resin, polyurethane (meth)acrylate, polyvinyl alcohol, polyvinylpyrrolidone, polyoxazoline, polyglycerin, polyglycerin-modified silicone, polyglycerin(meth)acrylate, cellulose, polyethylene glycol, and polypropylene glycol, as a component of the layer (B).
11 . A method for manufacturing the bio-electrode according to claim 1 , the method comprising forming the layer (A) on the opposite side of the substrate from the side having the anti-reflective structure, by applying a solution comprising metal nanowires, or by printing an electro-conductive paste containing conductive particles thereon.