Continuous coating of discrete areas of a flexible web

The use of surface energy (wettability) contrast to direct liquid into designated areas, so that flexible substrates can be coated with a discrete pattern in a continuous, roll‐to‐roll manner is described. The method makes use of a substrate prepatterned with lyophilic and lyophobic regions. When this substrate is over‐coated with the target liquid, the liquid withdraws from the lyophobic areas and collects on the lyophilic ones. The surface‐energy pattern and the liquid can be applied by a variety of different methods, but we have focused on printing the patterns by flexography and slide coating the target liquid. A benefit of the technique is that coatings of subsequent layers with the same pattern are self‐aligned with the previous layer, since they are directed by the same surface energy pattern. The capability is also demonstrated to perform simultaneous multi‐layer patterned coating in a single‐pass operation. © 2007 American Institute of Chemical Engineers AIChE J, 2007