仿生微纳结构

Contact Angle Meter
Water droplet contact angles of smooth-surface PMMA sheet
(a) without silane treatment: 70°±2°, (b) with silane treatment: 105°±2° (c) when the surface was turned upside down yet the water droplet remained attached to the surface.
Water droplet contact angles of hierarchical micro- and nanostructured PMMA sheet
(a) without silane treatment: 134°±2°, (b) with silane treatment: 159°±2°, and (c) when the water droplet remained attached to the surface and retained its sphericalshape even though the surface was turned upside down.
Bioinspired Science and Technology
(Artificial rose petal surface based on hierarchical micro- and nanostructures)
Article was from Thin Solid Films Accepted 6 July 2011 Available online 18 July asurement
In the paper .They prepared four different surfaces, namely, smooth nanostructured,microstructured, and hierarchically micro-nanostructured Surfaces. These four types of surfaces were also chemically treated to reduce the surface energy using silane.Silane was deposited by vacuum vapor deposition process in the desiccator .Then ,through the Contact Angle Meter to measured the water contact angles
SEM images of the surface and schematic representations of the geometric models: (a, c) lotus leaf and (b, d) red rose petal.
How to fabricate the micro-nano structure
Name: Sutudent ID :
Introduction
In this paper, it presents an artificial rose petal composed of hierarchical micro- and nanostructures on a polymethyl methacrylate surface. The petal effect implies that the surface has a high adhesion force in spite of being in a super-hydrophobic state, while the lotus effect implies that the surface has a low adhesion force when it is in a super-hydrophobic state
After removing the silicon nitride layer, we sputtered the aluminum on the micro-patterned substrate The target thickness of aluminum was 1 μm
An AAO process was performed on a sputtered aluminum layer to fabricate nanostructures on the microstructure
Many researchers are interested in biological micro- and nanostructured surfaces because these surfaces exhibit attractive properties
Micron structure of mountains
Conclusion
In summary, In the paper they present the fabrication of an artificial rose petal composed of hierarchical micro- and nanostructures on a PMMA surface. The concave mold of hierarchical micro- and nanostructures was fabricated by using a combination of silicon anisotropic wet etching and aluminum anodizing processes and the convex replica of hierarchical micro- and nanostructures was duplicated by using a hotembossing process Furthermore, the water droplet on the surface was steadily attached and retained its spherical shape even when the surface was turned upside down.so ,for this micro-nanostructures,it could be applied to nano-optics and nano-bio devices.
Water droplet contact angles of nanostructured PMMA sheet
(a) without silane treatment: 101°±2°, (b) with silane treatment: 112°±2°, and (c) when the surface was turned upside down yet the water droplet remained attached to the surface.
From the above examples .we may feel that nature is so wonderful. Especially. When we use electron micro-scope observe their microstructure, we found that most of them are complex micro-nanostructures
the lotus effect state
Branch of nanoscale structures
The butterfly's wing water rolling direction feature
water skipper legs structure
House lizard toes structure
In this paper, convex nanostructures on the pyramidal microstructures were duplicated from concave micro- and nanostructuremolds. First, a concave mold was fabricated, and then, the convex structure was replicated by using the convex mold. The concave molds were fabricated by silicon anisotropic wet etching and aluminum anodizing processes, and the convex replica was fabricated by a hotembossing process
Water droplet contact angles of microstructured PMMA sheet
(a) without silane treatment: 110°±2°, (b) with silane treatment: 138°±4°, and (c) when the surface was turned upside down yet the water droplet remained attached to the surface
From the pictures. We found that the approximate facet length and height of the pyramidal microstructurewere 15 μm–20 μm, and the nanofolds were approximately 700–800 nm in width
Process of wet etching
First, a concave pyramidal microstructure was fabricated by asilicon anisotropic wet etching process using 20-wt.% potassiumhydroxide (KOH). Silicon nitride (Si3N4) was used as the etching mask in the KOH etching process Etching process was performed for 20 min. Pyramidal microstructures were fabricated on the entire surface of a 4-in. silicon wafer
But
how can we fabricate this complex micro-nanostructures
Fabrication of artificial petal surfaces
The geometric shapes and sizes of artificial petal surfaces were designed on the basis of a biological rose petal. The surface structures of the biological rose petal consisted of microstructures, such as pyramids, and nanofolds on the surface of the microstructures