Amorphous blends of poly(zwitterions) and zwitterionomers of the ammonioalkoxydicyanoethenolate type with some alkali metal salts

Poly(zwitterions) and zwitterionomers of the ammonioethoxydicyanoethenolate type (functional dipolar unit R ₃N⁺–(CH ₂) ₂–O–CO–C^?–(CN) ₂, µ = 25.9 D) show the very specific property of solvation of some alkali metal salts to yield amorphous blends. For homopolymers in the (meth)acrylic series, solvation is observed up to a ratio r = salt]/zwitterion] of 1 for LiClO ₄ and NaSCN and of 0.5 for NaCF ₃SO ₃: it results in a significant plasticization (increasing order LiClO ₄ < NaSCN < NaCF ₃SO ₃) and in the development in some cases of a poorly defined (lamellar?) local order, as evidenced by the presence of a single broad peak in the small‐angle x‐ray scattering (SAXS) patterns (Bragg distances of about 15–20 Å). For the amorphous blend of a biphasic poly(tetramethyleneoxide) segmented zwitterionomer and NaCF ₃SO ₃ (r = 0.5), selective solvation of the salt in the hard zwitterionic domains induces a transition from a lamellar structure (zwitterionic sublayer of about 9 Å thickness) to an hexagonal packing of ionic‐zwitterionic cylinders (radius of about 15 Å). Ionic conductivity, measured in a narrow range of temperature just above the glass transition temperature, is characterized for most systems by an activation energy of about 1–1.8 eV; the drastic decrease of the conductivity by a factor of 10 ³, when going from the homopolymer to the zwitterionomer blends, is typical of the inhibition of the ionic percolation process by the lack of connectivity of the ionic‐zwitterionic domains. Copyright © 2001 John Wiley & Sons, Ltd.