Abstract: Compositions and cation exchange membranes having low brittleness, low ER, good pH stability and good PS obtainable by curing a composition comprising: (a) a first crosslinking agent comprising an anionic group and at least two polymerisable groups; (b) a second crosslinking agent comprising at least 5 vinyl groups and being free from ionic groups; and (c) a third crosslinking agent comprising 2, 3 or 4 polymerisable groups and being free from ionic groups.

Abstract: A bipolar membrane comprising an anion exchange layer and a cation exchange layer, wherein the cation exchange layer is obtainable by curing a composition comprising: (a1) a first crosslinking agent comprising an anionic group and at least two polymerisable groups; (b1) a second crosslinking agent comprising at least two polymerisable groups being free from anionic groups; wherein the molar ratio of component (a1) to component (b1) is at least 1.

Abstract: A bipolar membrane comprising an anion exchange layer and a cation exchange layer, wherein the cation exchange layer is obtainable by curing a composition comprising: (a) a first crosslinking agent comprising an anionic group and at least two polymerisable groups; (b) a second crosslinking agent comprising at least 5 vinyl groups and being free from ionic groups; (c) a third crosslinking agent comprising 2, 3 or 4 polymerisable groups and being free from ionic groups.

Abstract: Cationically charged membranes obtainable from curing a composition comprising an aromatic heterocyclic compound, wherein the aromatic heterocyclic compound comprises: a) an aromatic heterocyclic ring: b) at least two polymerisable groups: and c) a cationically charged nitrogen atom. The membranes are mechanically strong, have a high charge density and maintain good permselectivity even after exposure to harsh conditions such as extremes of pH.

Abstract: A polymer film obtainable from curing a composition comprising: (a) a curable ionic compound comprising a bis(sulfonyl)imide group; and (b) a curable non-ionic compound comprising at least 4 vinyl groups.

Abstract: A polymer film comprising anionic groups and 0.008 to 25 mg/g of each of components (a) and (b): (a) a crosslinking agent which is free from fluoro groups and comprises a group of Formula (I); and (b) a non-ionic crosslinking agent; Formula (I) wherein M+ is a cation and * indicates the attachment points to other elements of the crosslinking agent.

Abstract: A polymer film obtainable by polymerising a composition comprising: (a) a compound Formula (I); wherein: R is C1-4-alkyl, NH2 or C6-12-aryl; and M+ is a cation; (b) a monomer comprising at least two polymerisable groups; and (c) a solvent. Also claimed are compositions and processes for making the polymer films.

Abstract: A membrane comprising an anion exchange layer (AEL) and a cation exchange layer (CEL) wherein the CEL is obtainable by a process comprising curing a curable composition comprising a compound of Formula (I): Formula (I) wherein: X is is of the formula —OCnH2n+1 or —OCqH2q?1, wherein n has a value of of 1 to 6 and q has a value of 5 or 6; and m has a value of 1 or 2.

Abstract: A membrane comprising: a) a first layer comprising a first polymer or a fourth polymer having ionic groups of polarity opposite to the polarity of the ionic groups of the third polymer; b) a second layer comprising a second polymer having ionic groups of polarity the same as the polarity of the ionic groups of the third polymer; and c) a third layer comprising a co-continuous polymeric network of (i) a third polymer having ionic groups and a network of pores; and (ii) a fourth polymer having ionic groups of polarity opposite to the polarity of the ionic groups of the third polymer; wherein layer c) is interposed between layer a) and layer b) and the third polymer is obtainable by a process comprising phase separation of the third polymer from a curable composition used to prepare the third polymer.

Abstract: A composite membrane comprising: a) a first layer comprising a first porous support and a first ionic polymer present in the pores of the first porous support; b) a second layer comprising a second porous support and a second ionic polymer present in the pores of the second porous support; c) a third layer comprising a third porous support, a third ionic polymer and a fourth ionic polymer, wherein the third ionic polymer is present in the pores of the third porous support; wherein: (i) one of the first ionic polymer and the second ionic polymer is a cationic polymer and the other is an anionic polymer; (ii) the third layer c) is interposed between the first layer a) and the second layer b); (iii) the third ionic polymer comprises a network of pores and the fourth ionic polymer is present within the pores of the third ionic polymer; and (iv) one of the third ionic polymer and the fourth ionic polymer is a cationic polymer and the other is an anionic polymer.

Abstract: A polymer film obtainable by curing a composition comprising a compound of Formula (I) wherein: R? is vinyl, epoxy C1-3_alkylenethiol: n has a value of 1 or 2; m has a value of 1, 2 or 3; M?+ is a cation; wherein X is as defined in the claims; and wherein the molar fraction of the compound of Formula (I) in relation to all curable compounds in the composition is greater than 0.25. Also claimed are compositions, processes membranes and their uses.

Abstract: A membrane stack comprising the following components: (a) a first ion diluting compartment (D1); (b) a second ion diluting compartment (D2); (c) a first ion concentrating compartment (C1); (d) a second ion concentrating compartment (C2); and (e) a membrane wall (CEM1, mAEM, mCEM, AEM, CEM2) between each compartment and on the outside of the first and last compartment of the stack; wherein: (i) each membrane wall comprises a cation exchange membrane (CEM1, mCEM, CEM2) or an anion exchange membrane (mAEM, AEM) and the order of the cation and anion exchange membranes alternates from each wall to the next; (ii) the membrane walls (mAEM, mCEM) on each side of compartment (a) both have a higher monovalent ion selectivity than the corresponding membrane walls (AEM, CEM2) on each side of compartment (b); and (iii) the stack further comprises a means for communicating fluid between compartments (a) and (b).

Abstract: A redox flow battery system (10) comprises an electrochemical cell (11) divided into first and second compartments (11a, 11b) by a porous membrane (13). Each of the first and second compartment (11a, 11b) houses an electrode. An electrolyte storage tank (14) has a first volume (14a) and a second volume (14b) separated from the first volume by a movable separator (15). The first volume (14a) of the storage tank (14) is in fluid communication with the first compartment (11a) and the second volume (14b) of the storage tank (14) is in fluid communication with the second compartment (11b). The system (10) also includes a flow control system configured to move fluid between the first volume (14a) of the storage tank and the second volume (14b) of the storage tank through the first and second compartments (11a, 11b) of the electrochemical cell (11). An associated method is also described.

Abstract: A composite ion exchange membrane obtainable by a process comprising reacting an ionically-charged membrane with a composition comprising: (a) a monofunctional ethylenically unsaturated monomer having an ionic charge opposite to the charge of the ionically-charged membrane; and (b) a crosslinking agent comprising two or more ethylenically unsaturated groups; wherein the molar ratio of (b):(a) is lower than 0.04 or is zero.

Abstract: A composite ion exchange membrane comprising a cationically-charged membrane and an oppositely charged compound covalently bound thereto, the composite ion exchange membrane having: (i) a zeta-potential lower than ?8 mV; and (ii) an effective charge lower than 20 ?mol/m2.

Abstract: A membrane obtainable from curing a composition comprising: (i) a curable compound comprising at least two (meth)acrylic groups and a sulphonic acid group and having a molecular weight which satisfies the equation: MW<(300+300n) wherein: MW is the molecular weight of the said curable compound; and n has a value of 1, 2, 3 or 4 and is the number of sulphonic acid groups present in the said curable compound; and optionally (ii) a curable compound having one ethylenically unsaturated group; wherein the molar fraction of curable compounds comprising at least two (meth)acrylic groups, relative to the total number of moles of curable compounds present in the composition, is at least 0.25.

Abstract: A membrane stack comprising the following components: (a) a first ion diluting compartment (D1); (b) a second ion diluting compartment (D2); (c) a first ion concentrating compartment (C1); (d) a second ion concentrating compartment (C2); and (e) a membrane wall (CEM1, mAEM, mCEM, AEM, CEM2) between each compartment and on the outside of the first and last compartment of the stack; wherein: (i) each membrane wall comprises a cation exchange membrane (CEM1, mCEM, CEM2) or an anion exchange membrane (mAEM, AEM) and the order of the cation and anion exchange membranes alternates from each wall to the next; (ii) the membrane walls (mAEM, mCEM) on each side of compartment (a) both have a higher monovalent ion selectivity than the corresponding membrane walls (AEM, CEM2) on each side of compartment (b); and (iii) the stack further comprises a means for communicating fluid between compartments (a) and (b).

Abstract: A composite ion exchange membrane comprising a cationically-charged membrane and an oppositely charged compound covalently bound thereto, the composite ion exchange membrane having: (i) a zeta-potential lower than ?8 mV; and (ii) an effective charge lower than 20 ?mol/m2.

Abstract: A composite ion exchange membrane obtainable by a process comprising reacting an ionically-charged membrane with a composition comprising: (a) a monofunctional ethylenically unsaturated monomer having an ionic charge opposite to the charge of the ionically-charged membrane; and (b) a crosslinking agent comprising two or more ethylenically unsaturated groups; wherein the molar ratio of (b):(a) is lower than 0.04 or is zero.

Abstract: A membrane obtainable from curing a composition comprising: (i) a curable compound comprising at least two (meth)acrylic groups and a sulphonic acid group and having a molecular weight which satisfies the equation: MW<(300+300n) wherein: MW is the molecular weight of the said curable compound; and n has a value of 1, 2, 3 or 4 and is the number of sulphonic acid groups present in the said curable compound; and optionally (ii) a curable compound having one ethylenically unsaturated group; wherein the molar fraction of curable compounds comprising at least two (meth)acrylic groups, relative to the total number of moles of curable compounds present in the composition, is at least 0.25.