Wet chemical noble metal coating

Abstract

The invention relates to a method for coating a substrate with a noble metal layer, which comprises the following steps: (i) providing a substrate; (ii) applying a liquid noble metal ink to the substrate, wherein the noble metal ink contains less than 10 percent by weight of noble metal, based on the total weight of the noble metal ink; and (iii) heating the liquid noble metal ink, and thereby forming a noble metal layer on the substrate.

What is claimed is: 
     
         1 . A method for coating a substrate with a noble metal layer, comprising the steps of:
 (i) providing a substrate,   (ii) applying a liquid noble metal ink to the substrate, wherein the noble metal ink contains less than 10 percent by weight of noble metal, preferably less than 9, 8, 7, 6 or less than 5 percent by weight of noble metal, based on the total weight of the noble metal ink,   (iii) heating the liquid noble metal ink and thereby forming a noble metal layer on the substrate.   
     
     
         2 . The method according to  claim 1 , wherein in step (iii) a noble metal layer is formed which has a layer thickness of less than 100 nm, preferably less than 50 nm or less than 30 nm. 
     
     
         3 . The method according to  claim 1 , wherein in step (iii) a noble metal layer is formed which is completely closed. 
     
     
         4 . The method according to  claim 1 , wherein in step (iii) a noble metal layer is formed which has a roughness Ra of less than 100 nm. 
     
     
         5 . The method according to  claim 1 , wherein the noble metal ink is particle-free. 
     
     
         6 . The method according to  claim 1 , wherein in step (iii) 50 to 500 µg, preferably 50 to 200 µg, of noble metal per cm 2  of substrate surface are applied to the substrate. 
     
     
         7 . The method according to  claim 1 , wherein the noble metal layer obtained in step (iii) makes up less than 10 percent by volume, preferably less than 5 or less than 1 percent by volume, of the entire substrate-noble metal layer composite. 
     
     
         8 . The method according to  claim 1 , wherein the liquid noble metal ink is applied by means of inkjet printing, screen printing, stamp printing, application by means of felt, dispensing, dip coating, spray coating, die coating or spin coating. 
     
     
         9 . The method according to  claim 1 , wherein the substrate provided with the noble metal layer is suitable for implantation in the animal or human body. 
     
     
         10 . The method according to  claim 1 , wherein the substrate provided with the noble metal layer is a belt, a cylinder, a tube, a sphere, a wire, or preferably a catheter, a stent, an electrode, a sensor or a stylet. 
     
     
         11 . The method according to  claim 1 , wherein the substrate provided with the noble metal layer comprises a noble metal, a base metal or a non-metal. 
     
     
         12 . The method according to  claim 1 , wherein the noble metal ink comprises platinum, silver or gold. 
     
     
         13 . The method according to  claim 1 , wherein the noble metal ink comprises an organic noble metal complex having diolefin and C6-C18 monocarboxylate ligands of the type [(L1L2)Pt[O(CO)R 1 ] 2 ] n , [LPd[O(CO)R1]X] n , [LRh[O(CO)Rl]] m  or [LIr[O(CO)R1]] m , wherein L denotes a compound acting as a diolefin ligand, wherein X is selected from bromide, chloride, iodide and -O(CO)R2, wherein -O(CO)R1 and -O(CO)R2 denote identical or different non-aromatic C6-C18 monocarboxylic acid groups, and wherein n is a whole number ≥ 1 and m is a whole number ≥ 2. 
     
     
         14 . The method according to  claim 13 , wherein the organic noble metal complex is a compound with the formula [(L1L2)Pt[O(CO)R 1 ] 2 ] n , wherein n is equal to 1 or 2, L1L2 is cyclooctadiene or norbornadiene, and wherein R 1  represents a non-aromatic C7-C17 hydrocarbon group. 
     
     
         15 . The method according to  claim 13 , wherein the noble metal complex is a compound with the formula (COD)Pt[O(CO)C(CH 3 ) 2 C 6 H 13 ] 2 . 
     
     
         16 . The method according to  claim 12 , wherein the noble metal ink comprises a solvent which preferably comprises propylene glycol n-propyl ether and/or ethanol. 
     
     
         17 . A substrate having a noble metal layer obtainable by a method according to  claim 1 . 
     
     
         18 . A noble metal ink comprising less than 10 percent by weight of noble metal, preferably less than 9, 8, 7, 6 or less than 5 percent by weight of noble metal, based on the total weight of the noble metal ink, and a solvent, wherein the noble metal is present as an organic noble metal complex dissolved in the solvent. 
     
     
         19 . The noble metal ink according to  claim 18 , wherein the noble metal complex comprises diolefin and C6-C18 monocarboxylate ligands of the type [(L1L2)Pt[O(CO)R 1 ] 2 ] n , [LPd[O(CO)R1]X] n , [LRh[O(CO)R1]] m  or [LIr[O(CO)R1]] m , wherein L denotes a compound acting as a diolefin ligand, wherein X is selected from bromide, chloride, iodide and -O(CO)R2, wherein -O(CO)R1 and -O(CO)R2 denote identical or different non-aromatic C6-C18 monocarboxylic acid groups, and wherein n is a whole number ≥ 1 and m is a whole number ≥ 2. 
     
     
         20 . The noble metal ink according to  claim 18 , wherein the noble metal complex is a compound with the formula [(L1L2)Pt[O(CO)R 1 ] 2 ] n , wherein n is equal to 1 or 2, L1L2 is cyclooctadiene or norbornadiene, and wherein R 1  represents a non-aromatic C7-C17 hydrocarbon group. 
     
     
         21 . The noble metal ink according to  claim 18 , wherein the noble metal complex is a compound with the formula (COD)Pt[O(CO)C(CH 3 ) 2 C 6 H 13 ] 2 .