Synthesis of Photodegradable Surface Modifiers Based on Phosphonic Acid for Introducing Functional Groups onto a Substrate and Application for Patterned Deposition of Gold Nano-Particulate Ink

Abstract

Abstract Techniques for selective deposition of conductive inks, in particular metal nano-particulate inks, by using self-assembling monolayers (SAMs) mostly involve control of wettability with highly hydrophobic compounds. In this work, we focused on electrostatic interaction of metal nano-particles and investigated the influence of functional groups on the substrate upon selective deposition of metal nanoparticles. Surface modifiers bearing four kinds of functional groups (-OH, -NH2, -SH, -COOH) protected by a photodegradable 2-nitrobenzyl ester were synthesized and used to form SAMs on an indium tin oxide-coated glass substrate. UV-irradiation through a photomask generated the respective functional group in exposed regions. High-quality patterning of aqueous Au nano-particulate ink, which is negatively charged, was successfully achieved by spin coating onto amine-bearing SAMs. These results suggest the feasibility of micro-scale patterning based on electrostatic interaction between Au nano-particles and free amino groups introduced onto the substrate by photoirradiation-induced deprotection of surface-modifying agents.