Formation of solid layers on substrates
Disclosed is a method of forming on the surface of a substrate a first solid layer which is suitable for activating a chemical reaction to form a second layer thereon, the method comprising the steps of: applying to the surface of the substrate a first liquid comprising a curable composition and an activator for the second layer-forming chemical reaction; and curing the curable composition, thereby forming a first solid layer adhered to the surface of the substrate, capable of activating the second layer-forming chemical reaction. A second layer can then be formed on the substrate by bringing into contact with the first solid layer a second fluid comprising components of a second layer-forming chemical reaction, activated by the activator, thereby causing a second layer to be formed on the first solid layer.
1. A method of forming, on the surface of a substrate, a first solid layer which is capable of activating a chemical reaction to form a second layer thereon, the method comprising
applying a first liquid to the substrate surface, the first liquid comprising
a curable composition and
an activator for said second layer-forming chemical reaction, wherein the activator comprises a metal or metal-containing material and the weight ratio of the curable composition to the metal portion of the activator is greater than about 25:1;
wherein the curable composition comprises
a mixture of acrylate or methacrylate monomers and/or oligomers which polymerise and/or cross-link on curing, thereby hardening and forming a solid layer, including a proportion of acrylate or methacrylate monomers and/or oligomers having at least 3 cross-linkable functional groups, the curable composition further comprising
an initiator which generates free radicals in response to a stimulus to start a curing reaction; and
exposing the curable composition to said stimulus to cause free radical curing of the curable composition by polymerization and/or cross-linking to increase adhesion of the composition to the surface of the substrate, thereby forming a first solid layer having a thickness greater than 500 nm, capable of activating said second layer-forming chemical reaction after contact with a second fluid;
wherein the first liquid is such that the first solid layer includes a first chemical compound that is at least partially insoluble in the second fluid, and wherein the first solid layer includes a second chemical compound which is at least partially soluble, miscible or swellable in the second fluid.
2. A method according to claim 1 , further comprising bringing into contact the first solid layer and the second fluid that comprises metal ions and a reducing agent for chemical reaction, activated by the activator, to form the second layer.
3. A method according to claim 2 , wherein the second layer comprises a conductive metal layer.
4. A method according to claim 3 , wherein the second layer-forming chemical reaction is a reaction between the metal ions and the reducing agent to form the conductive metal layer.
5. A method according to claim 1 , wherein the weight ratio of the first chemical compound to the second chemical compound is greater than about 5:1.
6. A method according to claim 1 , wherein the first solid layer is formed on the substrate surface according to a pattern.
7. A method according to claim 6 , wherein the curable liquid is applied extensively to the substrate surface and selectively cured according to a pattern.
8. A method according to claim 1 , wherein the second fluid is deposited on the first solid layer by inkjet printing.
9. A method according to claim 1 , wherein the metal or the metal-containing material in the activator is a catalyst metal or a catalyst metal-containing material.
10. A method of fabricating an electrical item comprising the method of claim 1 .
11. A method of producing a battery comprising the method of claim 1 .
12. A method of producing an electrical connection between two components of a circuit comprising the method of claim 1 .
13. A method of producing a decorative feature comprising the method of claim 1 .
14. A method according to claim 1 wherein not more than 75% by weight of the total monomer/oligomer content of the first liquid comprises materials having 3 cross-linkable functional groups.
15. A method according to claim 1 wherein not more than 35% by weight of the total monomer/oligomer content of the first liquid comprises materials having 4 cross-linkable functional groups.
16. A method according to claim 1 wherein not more than 10% by weight of the total monomer/oligomer content of the first liquid comprises materials having 5 cross-linkable functional groups.
17. A method according to claim 1 wherein the stimulus is electromagnetic radiation.
18. A method according to claim 17 wherein the electromagnetic radiation is ultraviolet radiation.
19. A method according to claim 6 , wherein the first liquid is deposited onto the substrate surface according to a pattern by digital inkjet printing.
20. A method according to claim 1 , wherein the activator further comprises a reducing agent or a pH-altering reagent.