0.17 Chapter 5_introduction-nanomaterials.  (Page 2/3)

1. Ya = years ago.
2. Hand – grip = hand curves to grip the tool and stiffens at the base of the thumb and in the mid-hands to stabilize the hand and dissipate the force. This complex of traits gives dexterity in tool making and tool handling.
3. “When Early Hominines got a Grip”, Meeting Briefs, American Association of Physical Anthropologists, 9-13 April, 2013, Knoxville Tennese, Science, Vol. 340, 26 ^th April 2013, pp 426-427.

What is Nano-materials ?

Nanoscience = Study of nanoscale materials, properties and phenomena.

Nanoscale Materials = Specifically: ≤ A material 100 nm along one dimension (Out of three dimention.

Nanotechnology = Applications of nanoscience to industry and commerce.

"Wet" nanotechnology, which is the study of biological systems that exist primarily in a water environment.

"Dry" nanotechnology, which derives from surface science and physical chemistry, focuses on fabrication of structures in carbon (for example, fullerenes and nanotubes), silicon, and other inorganic materials.

Computational nanotechnology, which permits the modeling and simulation of complex nanometer-scale structures.

5.1. Examples of Nanoscience.

The blue color of the butterfly shown in Figure 5.2 is due to Nature’s remarkable nanotechnology — the blue color is known as “structural color” (i.e. no pigment) that originates from the nanostructure in the dorsal wing. The structure interferes with certain wavelengths of light to produce an beautiful . The underside of the wing , on the other hand is brown. Why?

Figure 5.2. Butterfly Morpho peleides limpida is an example of nanoscience.

Figure 5.3. Nanostructure in Butterfly’s wings produces the interference fringes.

Figure 5.4.The layered structure in Butterfly’s Wings, through alternate constructive and destructive interference, gives rise to coloured fringes.

In early morning , dew drops curl up to form pearl beads on the lotus leaf in a pond. This is an example of nanoscience. The micro-nanostructure of the lotus leaf exhibits super-hydrophobicity. Superhydrophobicity means repulsion of Lotus Leaf towards Water Dew Drops. Hence dew drops early in the morning curl up as pearl beads.

Figure 5.5. The water beads formation on lotus leaf is a beautiful example of superhyrophobicity.

5.1.1.Self cleaning in Morpho Aega.

Figure 5.6. The attraction to water is higher than the static friction force between the dirty particle( marked in red) and the pointy surface, the dirty particle will be absorbed by the droplet.

Morpho Aega, a species of Butterfly, has the ability to self clean its wings based on nano-sceience. In Figure 5.6, water-droplets are shown in blue. These water drops roll-off the wing in a “radial out” direction from the central axis of the butterfly body due to directional adhesion of the super-hydrophobic wing. The direction of rolling is tuned by controlling the air-flow by the posture of the wings. The water droplets adsorb the dirt particles by electro-static attraction and these droplets carry away the dirt as the droplets roll off.