Conductive ink for a rollerball pen and conductive trace formed on a substrate

A conductive trace formed by:

• providing a conductive ink in a rollerball pen, the conductive ink comprising:
• an aqueous solvent;
• conductive particles dispersed in the aqueous solvent at a concentration of at least about 30 wt. %, the conductive particles comprising conductive silver flakes and conductive silver nanoparticles, wherein a weight ratio of the conductive silver flakes to the conductive silver nanoparticles is at least about 1:1;
• and
• a dispersant coating the conductive particles at a loading level of from about 0.1 mg/m2 to about 0.8 mg/m2;
• moving the rollerball pen over a surface to deposit the conductive ink on the surface;
• and
• drying the conductive ink at room temperature, thereby forming a conductive trace.

A method of forming a conductive trace, the method comprising:

• providing a conductive ink in a rollerball pen, the conductive ink comprising:
• an aqueous solvent;
• conductive particles dispersed in the aqueous solvent at a concentration of at least about 30 wt. %, the conductive particles comprising conductive silver flakes and conductive silver nanoparticles, wherein a weight ratio of the conductive silver flakes to the conductive silver nanoparticles is at least about 1:1;
• and
• a dispersant coating the conductive particles at a loading level of from about 0.1 mg/m2 to about 0.8 mg/m2;
• moving the rollerball pen over a surface to deposit the conductive ink on the surface;
• and
• drying the conductive ink at room temperature, thereby forming the conductive trace.