FABRICATION OF SELF-CLEANING POLYVINYLIDENE FLUORIDE FILM

Self-cleaning surfaces have received a great deal of attention recently, both in theoretical studies and commercial applications. Lotus flower is a symbol of purity in Asian cultures, when growing from muddy waters it stays clean and uncontaminated. The "self-cleaning" surface of lotus leaf is hydrophobic and rough, showing a micro- and nona-scale morphology. The micro-reliefs of lotus leaf was mimicked using PVDF (Polyvinylidene Fluoride) film and the nano-scale peaks on top of the micro-reliefs was implemented by the reaction between CH3SiCl3 and the reactive groups of PVDF film treated by oxygen plasma. A lotus-leaf-like surface of the PVDF film was clearly observed by SEM (Scanning Electronic Microscopy) and AFM (Atomic Force Microscope). Elemental composition analysis by XPS (X-ray Photoelectron Spectroscopy) revealed that the material of the nanostructure of PVDF film was polymethylsiloxanes. The superhydrophobic property of the mimicked self-cleaning surface was validated by the water contact angle and sliding angle on the lotus-leaf-like PVDF film, which are 165 degrees and 4 degrees, respectively. In this case, water drops can easily move across the PVDF surface, carrying dirt particles away, leaving no contamination.