Membranes

An anion exchange membrane obtainable by curing a curable composition comprising:

• (a) a monomer (a) of Formula (I)
• wherein:
• each n independently has a value of 1 or 2;
• L is a non-aromatic linking group;
• each X− independently is an anion;
• AR1 and AR2 each independently comprise an aromatic group;
• and
• (i) Ra, Rb, Rc and Rd are each independently an optionally substituted C1-3-alkyl group or an optionally substituted C2-3-alkenyl group;
• or
• (ii) Ra and Rb, together with the positively charged nitrogen atom to which they are attached, form an optionally substituted 5- or 6-membered ring and Rc and Rd are each independently an optionally substituted C1-3-alkyl group or an optionally substituted C2-3-alkenyl group;
• or
• (iii) Ra and Rb, together with the positively charged nitrogen atom to which they are attached, form an optionally substituted 5- or 6-membered ring and Rc and Rd, together with the positively charged nitrogen atom to which they are attached, form an optionally substituted 5- or 6-membered ring;
• or
• (iv) one of Ra and Rb is an optionally substituted C1-3-alkyl group or an optionally substituted C2-3-alkenyl group and the other of Ra and Rb, together with the group of formula AR1—(CH2)n—N+, forms an optionally substituted 5- or 6-membered ring, and Rc and Rd are each independently an optionally substituted C1-3-alkyl group or an optionally substituted C2-3-alkenyl group;
• or
• (v) one of Ra and Rb is an optionally substituted C1-3-alkyl group or an optionally substituted C2-3-alkenyl group and the other of Ra and Rb, together with the group of formula AR1—(CH2)n—N+, forms an optionally substituted 5- or 6-membered ring, and Rc and Rd, together with the positively charged nitrogen atom to which they are attached, form an optionally substituted 5- or 6-membered ring;
• or
• (vi) one of Ra and Rb and one of and Rc and Rd is an optionally substituted C1-3-alkyl group or an optionally substituted C2-3-alkenyl group and the other of Ra and Rb, together with the group of formula AR1—(CH2)n—N+, forms an optionally substituted 5- or 6-membered ring, and the other of Rc and Rd, together with the group of formula N+—(CH2)n-AR2, forms an optionally substituted 5- or 6-membered ring;
• or
• (vii) one of Ra and Rb is an optionally substituted C1-3-alkyl group, an optionally substituted C2-3-alkenyl group, and the other of Ra and Rb is connected to L, forming an optionally substituted ring, and Rc and Rd are each independently an optionally substituted C1-3-alkyl group or an optionally substituted C2-3-alkenyl group;
• or
• (viii) one of Ra and Rb is an optionally substituted C1-3-alkyl group, an optionally substituted C2-3-alkenyl group, and the other of Ra and Rb is connected to L, forming an optionally substituted ring, and one of Rc and Rd is an optionally substituted C1-3-alkyl group or an optionally substituted C2-3-alkenyl group and the other of Rc and Rd is connected to L, forming an optionally substituted ring;
• wherein:
• (I) at least one of AR1 and AR2 comprises a curable ethylenically unsaturated group;
• (II) the monomer (a) of Formula (I) comprises at least two curable ethylenically unsaturated groups;
• and
• (III) the molar fraction of component (a) in relation to all curable components of the curable composition is at least 0.90.