Superhydrophobic fabrics produced by electrospinning and chemical vapor deposition

A versatile method to produce superhydrophobic fabrics by combining electrospinning and initiated chemical vapor deposition (iCVD) is reported. In this study, poly(caprolactone) (PCL) was first electrospun and then coated with a thin layer of hydrophobic polymerized perfluoroalkyl ethyl methacrylate (PPFEMA) by iCVD. The hierarchical surface roughness inherent in the PCL electrospun mats and the extremely low surface free energy of the coating layer obtained by iCVD yields stable superhydrophobicity with a contact angle of 175 degrees and a threshold sliding angle less than 2.5 degrees for a 20 mg droplet. This PPFEMA-coated PCL mat was also shown to exhibit at least grade 8 oleophobicity. Hydrophobicity was demonstrated to increase monotonically with a reduction in diameter among bead-free fibers and with the introduction of a high density of relatively small diameter beads. The systematic effect of fiber morphology on superhydrophobicity was also investigated theoretically and experimentally using both beaded and bead-free fibers with diameters ranging from 600 to 2200 nm.