Catalyst ink for three-dimensional conductive constructs
View Patent ↗A method of constructing conductive material in arbitrary three-dimensional (3D) geometries, such as 3D printing. The method may include selective application of an aerosol-based colloidal solution containing a catalytic palladium nanoparticle material onto a substrate and then immersion of the coated substrate into an electro-less plating bath for deposition of conductive copper material. The above steps may be repeated to create arbitrary 3D geometric constructs containing conductive metallic patterns.
1. An arbitrary three-dimensional construct prepared by
i. preparing a catalyst ink comprising a colloidal solution comprising a solvent and palladium nanoparticles; and
ii. depositing the catalyst ink from step (i) onto a surface of a substrate using aerosol jet printing;
iii. subjecting the substrate to electro-less plating to plate the palladium nanoparticles with copper; and
iv. repeating steps ii and iii until the three-dimensional construct is formed.
2. The construct of claim 1 further comprising sonicating the solvent in step i to disperse the palladium nanoparticles and to reduce aggregation of the palladium nanoparticles.
3. The construct of claim 1 wherein the solvent is selected from toluene, dimethylformamide, tetrahydrofuran, xylenes, and combinations thereof.
4. The construct of claim 1 wherein the catalyst ink further comprises a binder selected from poly-vinyl alcohol and carboxy-methyl cellulose or combinations thereof.
5. The construct of claim 1 wherein the palladium nanoparticles have an average particle size of from about 15 to about 400 nm.
6. The construct of claim 1 wherein the palladium nanoparticles are present in the catalyst ink in an amount of from 0.1 to 2.2 wt. %.
7. The construct of claim 1 wherein the substrate is selected from glass, plastic, ceramic, or metal.
8. The construct of claim 1 further comprising
v. applying a non-conductive layer prior to or after repeating steps ii and iii.
9. The construct of claim 8 wherein the catalyst ink further comprises a binder selected from poly-vinyl alcohol and carboxy-methyl cellulose or combinations thereof.
10. The construct of claim 8 wherein the palladium nanoparticles have an average particle size of from about 15 to about 400 nm.
11. The construct of claim 1 which construct is microelectronic circuitry.