Enhanced Assembly of Ag Nanoparticles for Surface-Independent Fabrication of Conductive Patterns

Polymer stamping is a reliable and cost-effective method for producing charged patterned surfaces. However, charge stability is limited, and they discharge steadily while immersed in polar solvents. Here, we applied polyelectrolytes as the stamping medium to increase this stability. Charged line patterns were fabricated by pressing a polydimethylsiloxane (PDMS) stamp covered with a polyethylenimine (PEI) solution against silicon, glass, or polystyrene. Then, the substrate was immersed in a solution of oppositely charged silver nanoparticles. Finally, silver crystallization on the deposited nanoparticle agglomerates was performed to homogenize the conductive surface. Fabricated structures were characterized by conductive AFM, SEM, and electrical measurements. Simulations of the electric field above the pattern and electrostatic deposition of nanoparticles were performed. The presented method allows for the production of high-resolution microstructures composed of parallel 45 mm paths with a width of 10 μm and a thickness below 100 nm. A conductivity of 10⁴ S/m is high enough to keep a commercial LED on.