In this work, we report a means of lithographically fabricating hydrophilic domains in an adhesive hydrophobic background. Because our hydrophobic layer is adhesive, it can be applied to a variety of substrate materials with a simple mechanical polish. This makes our technique easier and more flexible than covalent-bonding techniques which require chemical modifications, and must be tailored to particular material systems. We then discuss the characteristics of organic microlenses fabricated on these substrates using a dip-coating technique. The technique we use to fabricate microlens arrays is shown in Figure 1.
Process flow for hydrophobic patterning.
In the first step, an adhesive hydrophobic layer is mechanically applied to the substrate. An advantage of using adhesion, rather than covalent bonding as a means of depositing a hydrophobic layer is that the same hydrophobic material can be used with a variety of substrate material systems. Regardless of what material is used, the substrate can then be lithographically patterned and the hydrophobic layer selectively etched away from the exposed regions. After a UV-cure the lenses become hard and stable. Our fabrication technique can easily be modified to achieve double-sided convex lenses.