Anti-adhesion Mechanisms of Nepenthes Waxy Slippery Zone Surface

doi:10.3901/JME.2015.23.103

Abstract

Abstract: The micro-topography and geometrical parameters of the surface of nepenthes waxy slippery zone are characterized by atomic force microscope (AFM) and environment scanning electron microscope (ESEM). An individual domain of the waxy slippery zone surface is scanned by AFM with different normal forces applied, showing no difference in the topography and without pollutant adhering to the probe tip after scanning. Colloidal probe, which is made by gluing a 15 μm silica sphere onto the probe cantilever equipped with no tips, is employed to behave as a single seta contacting with the surface of nepenthes waxy slippery zone. Adhesion and friction forces of the waxy zone surface are measured and compared with those of polishing papers. Considering the effect of surface physicochemical properties on its adhesion ability, contact angles of polar (water) and non-polar (diiodomethane) liquids on the waxy zone surface and polishing papers with a similar roughness are measured by contact angle measuring device. The results show that a single crystal of waxy zone is of the mechanical stability, thus disclaiming the contamination hypothesis. The contact area at the interface can be reduced efficiently by the surface roughness of waxy zone, which, to some extent, decreases its adhesion and friction forces. The super-hydrophobic property and low surface energy of the waxy zone, combined with each other to form an anti-adhesion effect on the nepenthes waxy slippery zone, are another factor in reducing the surface adhesion and friction forces.

Key words: anti-adhesion, low surface energy, nepenthes, roughness, super-hydrophobic

BI Kedong, SONG Xiaochuang, WANG Yujuan, YANG Juekuan, CHEN Yunfei. Anti-adhesion Mechanisms of Nepenthes Waxy Slippery Zone Surface[J]. Journal of Mechanical Engineering, 2015, 51(23): 103-109.

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