(515b) Superhydrophobic Surfaces Through Micromolding Surface-Initiated Polymerization

Nature provides a vast and highly optimized array of surface architectures that have given plants and animals unique advantages in their environments.  In particular, hundreds of plant species are equipped with superhydrophobic leaves, which minimize disease threat and effectively channel rainwater near the roots for rapid uptake.  This research presentation introduces a new method to prepare superhydrophobic coatings that replicate the architectures of superhydrphobic leaves but have diverse surface and polymer chemistries that are not confined by nature’s building blocks.  Termed micromolding surface-initiated polymerization, we first form the mold of a superhydrophobic leaf, fill that mold with a liquid monomer, and press the monomer-filled mold against a surface that has been initiated for polymerization.  The growing polymer chains are confined by the mold and the surface features become positive replicas of the original leaf.  We will demonstrate the use of this method to replicate both natural and artificial surfaces with a partially fluorinated polymer that exhibits ultralow critical surface tensions and is prepared by surface-initiated ring-opening metathesis polymerization to exhibit robust attachment to the underlying surface.  The strengths and limitations of this technique to prepare superhydrophobic coatings from source plants such as Aristolochia esperanzae and Trifolium repens will be described, as well as the relation of surface topography to the wetting and barrier properties of the coating.  The presentation will also describe strategies to boost the yield and thickness of the polymerization so that larger scale topographies can be accurately reproduced.