The authors would like to acknowledge useful conversations with Hudong Chen and Xiayio He. We thank Newell Washburn for his constructive remarks related to phase separation in asymmetric fluid mixtures. We also appreciate the assistance of John Hagedorn and Terry Griffin of the Information and Technology Laboratory at the National Institute of Standards and Technology in the flow visualization. Nicos S. Martys would like to acknowledge partial support from the National Institute of Standards and Technology Center for Theoretical and Computational Materials Science.