Figure - available from: Advanced Materials Interfaces
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The observation of the SP distribution on lotus leaf. a) The lotus leaf. There is an ellipse in the middle of the leaf. In the area of ellipse, the SP show a sharp decrease in density. b) The sketch of the lotus and the distribution of SP. The inset is the SEM image of SP. The scale is 50 μm. c) The magnified view of SP distribution. The space between two neighbor SP is ranging from 400 to 1000 μm.
Source publication
The surface topographies of natural surfaces play significant roles for improving the ability to adapt to the environment. The micropapilla of lotus leaf is always used to enhance its self‐cleaning performance. However, the function of the submillimeter papilla of lotus has not been well studied. In this study, it is found that the optimal distribu...
Citations
The robust self-cleaning of a lotus leaf is the most classic and powerful phenomenon in nature, whose hybrid papillae and biological wax guarantee its functions. The stability of the lotus leaf surface function is determined by its overall structural design, and is also the fundamental reason for its long-term survival in the natural environment. In fact, the durability of lotus leaf surface function is facilitated by the coordination of many factors which is why it is challenging to be investigated using bionic technology. In this review, we comprehensively examined the synergistic effects of flexible characteristics, surface topography, hollow interlayers, leaf shape, and bent petioles on the structural stability of the lotus leaf surface. The key significance of these factors is in transferring the stress and strain on the surface downwards, reducing the load on the surface, improving the durability of the self-cleaning function, and ultimately ensuring respiration and photosynthesis of leaves in the natural environment. This comprehensive scrutiny offers a novel classical bionic scheme for enhancing the structural stability of a surface, which has potential for applications in deepwater self-cleaning, anti-drag, anti-icing, thermal insulation, and mechanical enhancement of membranes and buildings.
Superhydrophobic surfaces (SHS) for underwater drag reduction draw more and more attention owing to its promising and wide applications such as underwater vehicles, pipeline oil transportation, and aquaculture. However, the drag reduction properties are inextricably linked to the stability of air layer on SHS. This review highlights recent advances regarding SHS for underwater drag reduction in the past three years. First, the fundamental theories are briefly described. Next, the crucial influencing factors, which include dimension and arrangement of particles, layout, and shape of the microstructures, Reynolds number, and attack angle on underwater drag reducing performance of SHS are thoroughly listed. Furthermore, the superior or inferior of these manufacturing techniques is also individually illustrated. After that, the solutions of enhancing stability of the air layer are explicitly classified. Then, the practical applications and its potential value in ships and underwater vehicles, microchannels, as well as fabrics are briefly discussed. Finally, the remaining challenges and promising breakthroughs in the field of SHS for underwater drag reduction are clarified in depth.
A flexible porous interlayer is vital for stress transfer and energy storage; thus, it is widely used in the packaging field. The pomelo peel as a representative gradient porous topography is necessary for the protection of the seed and pulp. On subjecting the surface to an external force, the gradient porous interlayer of the pomelo peel not only generates a large deformation inside the peel for decreasing the stress on the pulp, but also decreases the deformation and stress at the upper surface for enhancing the stability of the surface topography. Combined with the surface structure design of the lotus leaf and gradient porosity interlayer of the pomelo peel, a sample with flexible multilevel topography surface and gradient porosity interlayer is successfully prepared herein for improving the impact resistance and extending the superhydrophobic/icephobic functions. This novel binary design has potential applications in rapid energy absorption, packaging, and thermal isolation.
