Curable composition and film

A curable composition comprising:

• at least one polyfunctional compound selected from the group consisting of a compound represented by General Formula (I) and a compound represented by General Formula (II);
• and
• an ionic polymer including a repeating unit represented by General Formula (IV),
• in General Formula (I), R's each independently represent a hydrogen atom or a methyl group, and L's each independently represent —O—, an alkylene group having 2 to 4 carbon atoms, or a divalent linking group formed by combination thereof,
• in General Formula (II), R1's each independently represent a hydrogen atom or a methyl group, R2 and R4 each independently represent —O—, an alkylene group having 1 to 4 carbon atoms, or a divalent linking group formed by combination thereof, R3 represents —O—, an alkylene group having 1 to 4 carbon atoms, a group represented by General Formula (III), or a divalent linking group formed by combination thereof, and L1 and L2 each independently represent a single bond or a group represented by General Formula (III),
• in General Formula (III), R1 represents a hydrogen atom or a methyl group, and * represents a bonding position, and
• in General Formula (IV), M1 represents a hydrogen atom or a methyl group, M2 represents a hydrogen atom, or a substituted or unsubstituted hydrocarbon group having 4 to 25 carbon atoms, A represents a substituted or unsubstituted alkylene group having 2 to 5 carbon atoms, and n represents an integer of 3 to 50.