Electroless copper plating polydopamine nanoparticles

A substrate having electrically interconnecting conductive traces, comprising:

• a surface wettable with an aqueous solution;
• a plurality of catalytic nanoparticles deposited on the wettable surface by inkjet printing a suspension of the plurality of catalytic nanoparticles in a volatile liquid in a pattern to form a line having edges, and evaporating the volatile liquid to form an inhomogeneous pattern of catalytic nanoparticles within the bounds of the inkjet printed pattern to redistribute the plurality of catalytic nanoparticles according to the coffee ring effect, the inhomogeneous pattern of catalytic nanoparticles having a single catalytic nanoparticle thick pattern of parallel lines comprising a higher concentration of catalytic nanoparticles at edges of the inkjet printed line spaced by a region of sparse catalytic nanoparticle deposition between the edges of the inkjet printed line;
• and
• an electrolessly plated conductive metal pattern, formed on and corresponding to the inhomogeneous pattern of catalytic nanoparticles, selectively forming conductive traces over the parallel lines of catalytic nanoparticles, and being insulating between the respective parallel lines.

A device, comprising:

• a substrate having a surface with at least one hydrophilic portion;
• a parallel line pattern of deposited catalytic nanoparticles on the surface formed by inkjet printing a suspension of the catalytic nanoparticles in a pattern to form a line having edges, and evaporating the suspension to form an inhomogeneous pattern of the catalytic nanoparticles within the bounds of the inkjet printed pattern, to redistribute the plurality of nanoparticles according to the coffee ring effect, the inhomogeneous pattern of catalytic nanoparticles having a single catalytic nanoparticle thick region, wherein the parallel line pattern comprises dense linear catalytic nanoparticle deposition regions within the hydrophilic portion, and a sparse catalytic nanoparticle deposition region between a respective pair of dense linear nanoparticle deposition regions in the hydrophilic portion;
• and
• an electrolessly plated metal selectively formed proximate to the catalytic nanoparticles, forming conductive traces in a pattern corresponding to the inhomogeneous pattern of catalytic nanoparticles in the dense linear catalytic nanoparticle deposition regions, and being electrically insulating between the respective pair of dense linear catalytic nanoparticle deposition regions.