Tailoring ink-substrate interactions via thin polymeric layers for high-resolution printing

TL;DR

This paper demonstrates that depositing nanometer-thin polymeric layers, especially PMMA, can precisely tailor surface properties to improve inkjet printing resolution and pattern stability on various substrates.

Contribution

It introduces a simple method using thermal decomposition of PMMA layers to control surface energy and wetting, enabling high-resolution printing of complex structures.

Findings

Wetting can be tuned by adjusting PMMA layer thickness.

High-resolution printing achieved on diverse substrate-ink systems.

Surface energy transition occurs near zero PMMA thickness.

Abstract

The surface properties of a substrate are among the most important parameters in the printing technology of functional materials, determining not only the printing resolution but also the stability of the printed features. This paper addresses the wetting difficulties encountered during inkjet printing on homogeneous substrates as a result of improper surface properties. We show that the wetting of a substrate and, consequently, the quality of the printed pattern, can be mediated through the deposition of polymeric layers that are a few nanometers thick. The chemical nature of the polymers determines the surface energy and polarity of the thin layer. Some applications, however, require a rigorous adjustment of the surface properties. We propose a simple and precise method of surface-energy tailoring based on the thermal decomposition of poly(methyl methacrylate) (PMMA) layers. A smooth transition in the wetting occurs when the thickness of the PMMA layer approaches zero, probably due to percolating the underlying surface of the substrate, which enables the inkjet printing of complex structures with a high resolution. In particular, the wetting of three substrate-ink systems was successfully adjusted using the thin polymeric layer: (i) a tantalum-oxide-based ink on indium-tin-oxide-coated glass, (ii) a ferroelectric lead zirconate titanate ink on a platinized silicon substrate, and (iii) a silver nanoparticle ink on an alumina substrate.