A poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fibrous surface with various bead-on-string structures was fabricated by electrospinning. PHBV was electrospun at various concentrations and then CF4 plasma treatment was employed to further improve the hydrophobicity of the PHBV fiber surfaces. The surface morphology of the electrospun PHBV mats was observed by scanning electron microscopy (SEM). The surface properties were characterized by water contact angle (WCA) measurements and X-ray photoelectron spectroscopy (XPS). The surface morphology of the electrospun PHBV fibrous mats with the bead-son-string structure varied with the solution concentration. The WCA of all of the electrospun PHBV mats was higher than that of the PHBV film. In particular, a very rough fiber surface including porous beads was observed when PHBV was electrospun from the solution with a concentration of 26 wt%. Also, its WCA further increased from 141 degrees to 158 degrees after CF4 plasma treatment for 150 s. PHBV can be rendered superhydrophobic by controlling the surface morphology and surface energy, which can be achieved by adjusting the electrospinning and plasma treatment conditions. (C) 2008 Elsevier Inc. All rights reserved.