Polymer relief microstructures by inkjet etching

Abstract

Inkjet etching can create a variety of structures in polymer films, such as (arrays of) holes or grooves. These form by dissolution where a solvent droplet hits the film, followed by droplet evaporation and polymer redeposition at its pinned contact line. The hole radius, R, scales with the total number of droplets printed at a spot, N_dr, as R ∝ (N_drV_dr)^0.34. The width of a groove, D, scales with the total number of drops per unit length N_dr/L as D ∝ (N_dr/L)^0.56. Theory predicts an exponent of ⅓ and ½, respectively. Possible applications of inkjet etching are in the field of rapid prototyping. Proof of principle for possible electronic applications is given by creating a patterned Cr/Au-bilayer. Printing a dispersion creates polymer composite structures with encapsulated nanoparticles, as shown by SFM.