Authors:
Lingna He
Dave F. Farson
Laboratory for Multiscale Processing and Characterization, The Ohio State University, 1248 Arthur E Adams Drive, Columbus, Ohio 43221 and Department of Materials Science and Engineering, The Ohio State University, 477 Watts Hall, 2041 College Road, Columbus, Ohio 43210

Jian Chen
Materials Science and Technology Division, Oak Ridge National Laboratory, One Bethel Road, P.O. Box 2008, MS-6095, Oak Ridge, Tennessee 37831-6095

John J. Lannutti
Department of Materials Science and Engineering, The Ohio State University, 477 Watts Hall, 2041 College Road, Columbus, Ohio 43210

Stan I. Rokhlin
Laboratory for Multiscale Processing and Characterization, The Ohio State University, 1248 Arthur E Adams Drive, Columbus, Ohio 43221 and Department of Materials Science and Engineering, The Ohio State University, 477 Watts Hall, 2041 College Road, Columbus, Ohio 43210

The effect of femtosecond laser irradiation on the wettability of electrospun poly(&eh;-caprolactone) fiber mesh substrates was studied. It was observed that water contact angles on treated substrates decreased as laser power increased. Nanometer-scale gold coating on the surfaces allowed the effect of change in morphology on wettability to be quantified independently from the effect of chemistry change. Morphology change and chemistry change were both found to have independent hydrophilic effects on the surface wettability change that increased with laser power. As laser power increased, the treated sample surface transitioned from a rough fibrous mesh to more as a porous flat film. A laser power of 4.5 mW was found to divide both the surface morphology change and morphology-induced wettability change into high-power and low-power regimes. The Cassie-Baxter model successfully predicted the wettability of gold-coated surfaces using measured characteristics of surfaces from both regimes. All the laser-treated and untreated surfaces investigated in this work exhibited robust hydrophobic behavior.