Fabrication of Self-Cleaning Polyvinylidene Fluoride Film

Abstract

Self-cleaning surfaces have received a great deal of attention recently, both in theoretical studies and commercial applications. Lotus flowers are a symbol of purity in Asian cultures; even though they grow in muddy waters, they remain clean and uncontaminated. The “self-cleaning” surface of their leaves is hydrophobic and rough, showing a micro- and nano-scale morphology. The micro-reliefs of lotus leaves are mimicked by using polyvinylidene fluoride (PVDF) film and the nano-scale peaks on top of the micro-reliefs are implemented by a reaction between CH3SiCl3 and the reactive groups of the PVDF film treated by oxygen plasma. A lotus leaf-like surface of the PVDF film is clearly observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Elemental composition analysis by x-ray photoelectron spectroscopy (XPS) reveals that the material of the nanostructure of the PVDF film is polymethylsiloxane. The superhydrophobic property of the mimicked self-cleaning surface is validated by the water contact and sliding angles on the lotus leaf-like PVDF film, which are 165°and 4°, respectively. In this case, water drops can easily move off the PVDF surface, carrying dust away and leaving a clean surface