Perfluorovinyl ionic compounds and their use in conductive materials

A membrane comprised of a crosslinked copolymer of at least two ionic compounds in which the negative charge is highly delocalized, corresponding to the formula [CF2═CF—A−]mMm+ in which:

• Mm+ is a proton or a metal cation having the valency m chosen from the alkali metal, alkaline earth metal, transition metal or rare earth metal ions or an organic onium cation or an organometallic cation, 1≦m≦3;
• A is an anionic group having one of the formulae (I) [—(CF2)n—SO2Z]−, (II) [—(O)n′—Φ—SO2Z]− or (III)
• n and n′ represent 0 or 1;
• Φ represents a condensed or noncondensed aromatic group, which may or may not carry one or more substituents and which may or may not comprise heteroatoms, or a polyharlongenated group —C6H(4−x−y)FxCly— (1≦x+y≦4);
• Z represents —O or one of the —NC≡N, —C(C≡N)2, —NSO2R or —C[SO2R]2 groups, Z being other than —O when n or n′ are zero;
• D represents a single bond, an oxygen atom, a sulfur atom, a —CO— carbonyl group or an —SO2— sulfonyl group;
• the groups X1 to X4,, hereinafter denoted by Xi, represent N, C—C≡N, CR, CCOR or CSO2R, it being understood that, in a pentacyclic group, the xi groups can be identical or different;
• R represents Y, YO—, YS—, Y2N—, F, RF═CqF2q+1 (preferably 0≦q≦12), CF2═CF—, CF2═CFCF2— or CF2═CF—O—, it being understood that, if 2 R substituents are present on the same group, they can be identical or different;
• Y represents H or a monovalent organic radical having from 1 to 16 carbon atoms chosen from alkyl, alkenyl, oxaalkyl, oxaalkenyl, azaalkyl, azaalkenyl, aryl or alkylaryl radicals or from the radicals obtained from the abovementioned radicals by substitution, in the chains and/or the aromatic part, by heteroatoms, such as halogens, oxygen, nitrogen, sulfur or phosphorus, it being understood that, if sulfur or phosphorus are present, they can optionally be bonded to substituted nitrogen or oxygen atoms, or else Y is a repeat unit of a polymeric backbone;
• and
• at least one of the said at least two ionic compounds has all R substituents selected from Y, YO—, YS—, Y2N—, F, or CqF2q+1, and at least one of the said at least two ionic compounds has at least one substituent R selected from CF2═CF—, CF2═CFCF2— or CF2═CF—O—.

A method for preparing a membrane, comprising the step of copolymerizing at least two ionic compounds in which the negative charge is highly delocalized, corresponding to the formula [CF2═CF—A−]mMm+ in which:

• Mm+ is a proton or a metal cation having the valency m chosen from the alkali metal, alkaline earth metal, transition metal or rare earth metal ions or an organic onium cation or an organometallic cation, 1≦m≦3;
• A is an anionic group having one of the formulae (I) [—(CF2)n—SO2Z]−, (II) [—(O)n′—Φ—SO2Z]− or (III)
• n and n′ represent 0 or 1;
• Φ represents a condensed or noncondensed aromatic group, which may or may not carry one or more substituents and which may or may not comprise heteroatoms, or a polyhalogenated group —C6H(4−x−y)FxCly— (1≦x+y≦4);
• Z represents —O or one of the —NC≡N, —C(C≡N)2, —NSO2R or —C[SO2R]2 groups, Z being other than —O when n or n′ are zero;
• D represents a single bond, an oxygen atom, a sulfur atom, a —CO— carbonyl group or an —SO2— sulfonyl group;
• the groups X1 to X4, hereinafter denoted by Xi, represent N, C—C≡N, CR, CCOR or CSO2R, it being understood that, in a pentacyclic group, the Xi groups can be identical or different;
• R represents Y, YO—, YS—, Y2N—, F, RF═CqF2q+1 (preferably 0≦q≦12), CF2═CF—, CF2═CFCF2— or CF2═CF—O—, it being understood that, if 2 R substituents are present on the same group, they can be identical or different;
• Y represents H or a monovalent organic radical having from 1 to 16 carbon atoms chosen from alkyl, alkenyl, oxaalkyl, oxaalkenyl, azaalkyl, azaalkenyl, aryl or alkylaryl radicals or from the radicals obtained from the abovementioned radicals by substitution, in the chains and/or the aromatic part, by heteroatoms, such as halogens, oxygen, nitrogen, sulfur or phosphorus, it being understood that, if sulfur or phosphorus are present, they can optionally be bonded to substituted nitrogen or oxygen atoms, or else Y is a repeat unit of a polymeric backbone;
• at least one of the ionic compounds carries only one CF2═CF— group and at least one of the ionic compounds carries at least two CF2═CF— groups, and
• forming a membrane with the copolymer.