Phragmites Communis Leaves with Anisotropy, Superhydrophobicity and Self-Cleaning Effect and Biomimetic Polydimethylsiloxane (PDMS) Replicas

Abstract

Phragmites communis leaf (PCL) is anisotropic, superhydrophobic and shows a self-cleaning effect. The water contact angle (WCA) values along the vertical and parallel vein directions on PCL are 153° ± 2° and 148° ± 2°, respectively. In contrast, the water sliding angle (WSA) values along the vertical and parallel vein directions for PCL are 12° ± 2° and 7° ± 2°, respectively. The epidermal wax makes the leaves intrinsically hydrophobic. The microstructure of the PCL surface shows sub-millimetre-, micron- and nanometre-scale structures. The sub-millimetre ridge structure is the main reason for the anisotropy of the leaves. The micron-scale papillae structure has a strong hydrophobic enhancement effect, and the nanoscale sheet structure is the key factor in achieving a stable Cassie state, as well as superhydrophobicity and self-cleaning activities. PCL-like polydimethylsiloxane (PDMS) samples fabricated by template transfer technology exhibited the sub-millimetre ridge structure and micron-scale papillae from the natural PCL; they also show obvious anisotropy and strong hydrophobicity and have a certain self-cleaning effect. The WCA and WSA values along the vertical and parallel vein directions on PCL are 146° ± 2°, 23° ± 2°, 142° ± 2° and 19° ± 2°, respectively. The preparation of a biomimetic PCL surface has broad application prospects in micro-fluidic control and the non-destructive transmission of liquids.

Study on the Drag Reduction Characteristics of the Surface Morphology of Paramisgurnus dabryanus Loach

“…The theory of bionic tribology has become popular in the field of drag reduction in recent decades. There are two main factors affecting the tribological characteristics of a surface: the composition of the material itself and the surface structure [2][3][4][5]. Hossein [6] used two different SiO 2 nanoparticle surfaces, modified with polydimethylsiloxane (PDMS) and beeswax.…”

From Extremely Water-Repellent Coatings to Passive Icing Protection—Principles, Limitations and Innovative Application Aspects

“…(see Figure 2), known in the scientific literature as superhydrophobic, superomniphobic or supernonwetting depending on the liquids involved [6][7][8][9][10], opens a broad range of potential practical relevance. It includes, but is not limited to self-cleaning surfaces [11][12][13], passive icephobic [14][15][16] and anti-bioadhesive coatings [17][18][19], systems for removal of oil contamination from water basins [20][21][22][23], anti-corrosive coatings [24][25][26], drag-reducing surfaces [27][28][29][30], pervaporation membranes [31,32], green engineering [33] or piezoresonance chemical and biological sensors [34][35][36][37][38]. [18,37,38].…”