Switchable materials, methods and uses thereof

A composite material that is reversibly switchable between a first form and a second form, said composite material comprising a solid and solid-supported switchable moiety attached to said solid via a linker, wherein the attachment to said solid does not comprise a Si—O—Si or S—Au bond, the switchable moiety comprising a functional group that is switchable between a neutral form associated with said first form of said composite material, and an ionized form associated with said second form of the composite material, wherein the linker is not a polyamine, and wherein the bulk properties of the solid are not modified when the composite material switches between the first form and second form, and which comprises:

• (i) the neutral form of the switchable moiety bound to a surface via a linker X as in the structure of formula 3a, or 3b, or 3c, or any rotational isomers thereof,
• wherein:
• N═CR3NR4R5, R3N═CNR4R5, R3NH═CR4NR5 are each switchable functional groups, wherein R3, R4, and R5 are independently H, a C1 to C10 aliphatic group that is linear, branched, or cyclic;
• a CkSim group where k and m are independently a number from 0 to 10 and k+m is a number from 1 to 10, a C5 to C10 aryl group, or a heteroaryl group having from 4 to 10 carbon atoms in the aromatic ring, each of which may be substituted;
• or, any combination of R3, R4, and R5, together with the atoms to which they are attached, are connected to form a cycle, or heterocycle, each of which may be substituted;
• n is an integer 1, 2 or 3;
• and
• X is bonded to the solid and the switchable functional group and is a monovalent or a divalent moiety, or, X is a monovalent or a divalent cycle, or heterocycle, each of which may be substituted;
• optionally, X and one or two of R3, R4, and R5, together with the atoms to which they are attached, are connected to form a cycle, or heterocycle, each of which may be substituted;
• and, wherein the alkylene, alkenylene and alkynylene moieties of X optionally comprise one or more amine, amide, ether, ester, thioether, thioester, silane, siloxane, or a combination thereof, within the hydrocarbon chain;
• or
• (ii) the ionized form of the switchable moiety bound to a surface via a spacer X as in the structure of formula 4a, or 4b, or 4c, or any rotational isomers thereof,
• wherein:
• (N═CR3NR4R5)+, (R3N═CNR4R5)+, (R3NH═CR4NR5)+ are each switchable functional groups, wherein R3, R4, and R5 are independently H, a C1 to C10 aliphatic group that is linear, branched, or cyclic;
• a CkSim group where k and m are independently a number from 0 to 10 and k+m is a number from 1 to 10, a C5 to C10 aryl group, or a heteroaryl group having from 4 to 10 carbon atoms in the aromatic ring, each of which may be substituted;
• or, any combination of R3, R4 and R5, together with the atoms to which they are attached, are connected to form a cycle, or heterocycle, each of which may be substituted;
• n is an integer 1, 2 or 3;
• and
• X is bonded to the solid and the switchable functional group and is a monovalent or a divalent moiety;
• or, X is a monovalent or a divalent cycle, or heterocycle, each of which may be substituted;
• optionally, X and one or two of R3, R4, and R5, together with the atoms to which they are attached, are connected to form a cycle, or heterocycle, each of which may be substituted;
• and, wherein the alkylene, alkenylene and alkynylene moieties of X optionally comprise one or more amine, amide, ether, ester, thioether, thioester, silane, siloxane, or a combination thereof, within the hydrocarbon chain.