Process Windows for Patterned Particulate Coatings

A variety of coated products require patches or patterns of coating to be formed during the coating process. Flexible electronic devices, for example, are composed of patterns of functional materials on a flexible substrate. The continuous processing of these devices in a “reel-to-reel ” fashion is frequently stated as a goal1. While there are several processing routes currently under exploration, this research concerns the use of chemically functionalized substrates (e.g., hydrophobic, hydrophilic) as a platform for simultaneous coating and patterning. Past research in on this topic has focused mainly on the dropping liquids onto patterns2; the few attempts at coating onto these surfaces have involved either ultralow coating speeds designed for assembly of monodisperse particles3 or unspecified speeds4. The primary goal of this research is to find process conditions for creating uniform patterned coatings on chemically functionalized substrates using a dip coating process. Silicon substrates with a pattern of hydrophilic lines and hydrophobic spacings were prepared using photolithography and treatment with a self assembled monolayer. The methods for substrate preparation were similar to those described by Fustin and coworkers3. These chemically patterned substrates were then dip-coated with an aqueous dispersion of silic