Stable tin free catalysts for electroless metallization

A method comprising:

• a) providing a substrate;
• b) applying an aqueous catalyst solution to the substrate, the aqueous catalyst solution comprises one or more antioxidants, nanoparticles of palladium metal and one or more compounds chosen from polymers having a formula:
• wherein R1, R2, R3, R4, R5, R6 and R7 are the same or different and chosen from —H, —CH2COOX, —C(O)—CH3, —C(O)—(CH2)z—CH3 and
• wherein n is an integer of at least 2, z is an integer of at least 1 and X is —H or a counter cation, and a reaction product of a polymer having a formula:
• wherein R9, R10, R11, R12, R13, R14, and R15 are the same or different and are chosen from —H, —CH3, —CH2CH3, —CH2OH, —[CH2CHR8]x—OH, —CH2CH(OH)CH3, —(CH2CHR8O)y—H, with the proviso that at least one of R9, R10, R11, R12, R13, R14, and R15 is —CH2OH, —[CH2CHR8]x—OH, —CH2CH(OH)CH3 or —(CH2CHR8O)y—H, wherein R8 is —H or —CH3, x and y are an integer of at least 1 and n and z are as described above, and a quaternary compound having a formula:
• wherein m is an integer from 1 to 16, Y is halogen, Z− is a counter anion, R16, R17 and R18 are the same or different and are —H, —CH3 or —(CH2)p—CH3, and R19 is —H or —CH3 and p is an integer of 1 to 9, and one or more cross-linking agents, the aqueous catalyst solution is free of tin;
• and
• c) electrolessly depositing metal onto the substrate using an electroless metal plating bath.