Biomimetic Artificial PVDF Film Reproduce the Superhydrophobic Property of a Lotus Leaf

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 hierarchical micro- and nano-scale structures. Stimulated by “lotus effect”, the microreliefs of lotus leaf was mimicked using PVDF film and the nano-scale protrusions on the top of the microreliefs were implemented by the mixed solution of dimethyldichlorosilane (DDS) and methyltrichlorosilane (MTS). A lotus-leaf-like surface of the PVDF film was clearly observed by SEM. Elemental composition analysis by XPS revealed that the nanostructure materials of PVDF film were polymethylsiloxane and polydimethylsiloxane. 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 155°and 4°, respectively. In this case, water drops can easily move across the PVDF film surface, carrying dirt particles away, leaving no contamination.