Abstract
The effect of femtosecond laser irradiation on the wettability of electrospun poly(ε-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.
| Original language | English |
|---|---|
| Article number | 012002 |
| Journal | Journal of Laser Applications |
| Volume | 25 |
| Issue number | 1 |
| DOIs | |
| State | Published - Feb 2013 |
Funding
This work is partially supported by the National Science Foundation under Grant Nos. EEC-0425626, EEC-0914790, and CMMI-0928315. Also, the authors are grateful for assistance from Mr. Mark Andio and Professor Patricia Morris for water apparent contact angle measurements, Mr. Peng He, Mr. Likai Li, and Professor Allen Yi for surface roughness measurements, and Mr. Houyin Zhang at Northwestern University for discussions on curve fitting using Gnuplot.
Keywords
- femtosecond laser ablation
- fiber
- morphology
- poly(ε-caprolactone)
- wettability