The largest increase of hydrophobicity was achieved for the UVNIL printed lotus surfaces using the acrylate formulation with lowest viscosity.
By disturbing crystallization during one-step coating-curing process, bionic lotus surfaces with controllable polymer nano-spheres/papules, nano-wires/fibers were firstly fabricated.
These nanocomposite lotus surfaces were, in addition, very hard with a microhardness above 400 MPa and particularly wear-resistant, and were self-cleaning with respect to hydrophobic contamination.
Starting with the discovery of hierarchically structured superhydrophobic lotus-surfaces [2, 15, 16] and the drag-reducing shark skin [17, 18], biomimetic surface technologies (e.g., lotus-, shark-, gecko-, moth eye-, and salvinia-effect) became a most important field [1, 19, 20].
The drag-reducing riblets of the shark skin were analyzed in the 1980s [17] and together with the self-cleaning lotus-surfaces [2, 15] ushered in a new era of biomimetic applications including the swimming competition in Olympic games (see Sect. 7.6).
the replicated surfaces were more durable than their nano-scale counterparts (nano-patterns, Figure 2C [13]), at microscale. Figure 7 (A) Real lotus leaf surface and (B - D) replicated surfaces of real leaves of lotus, colocasia and colocasia (dry), respectively [ [25], [26] ].
Such super-hydrophobicity of the natural lotus leaf surface enables self-cleaning of the leaf surface as the roll-off water droplets collect dusts in the path.
In this review, we provide basic information on lotus leaf surface and present recent advances in micro- and nanoscale engineering platforms inspired by the surface topographies of lotus leaves for various applications.
This study firstly reveals the existence of the discrete liquid-solid contact electrification phenomenon and concomitant net electrical charge generation on the natural lotus leaf surface.
The SEM micrographs (d f) show the lotus leaf surface in different magnifications: (d) The papilla epidermis, (e) single cell papilla, and (f) the epicuticular nonacosan-10-ol tubules on the cell surface.
