Design and preparation of biomimetic polydimethylsiloxane (PDMS) films with superhydrophobic, self-healing and drag reduction properties via replication of shark skin and SI-ATRP

Nature has provided a lot of important inspirations for human beings to create artificial methods to mimic the excellent performance of biological systems. Based on the shark skin pattern microstructure, the low surface energy and stimuli-responsive behavior of the poly(2-perfluorooctylethyl methacrylate) (PFMA) brush, a biomimetic PDMS film with superhydrophobic, self-healing and drag reduction properties was prepared by first replication of shark skin surface on PDMS film, followed by treatment with surface-initiated atom transfer radical polymerization (SI-ATRP) of FMA. The PFMA brushes can self-assemble into different hierarchical structures in ethanol or DMF, which make the biomimetic PDMS films show different contact angles. Having been damaged by finger-wipe with and without water respectively, the water repellency of the biomimetic PDMS films decreased. However, the surfaces recovered superhydrophobic property just by immersing the destroyed PDMS films into DMF which is good solvent for PFMA. The SEM images and XPS results demonstrated the changes of structure and chemical compositions of the biomimetic PDMS films surface in damage and self-healing processes. Rotational viscometer result showed the drag reduction rate of the biomimetic PDMS films surface can reach up to 21.7%. This research is expected to supply a novel method of controlling polymer brushes' self-assembly to prepare superhydrophobic and self-healing films.