Assignment 2: Properties of Nanomaterials (NT-512) PDF

MAULANA AZAD NATIONAL INSTITUTE OF TECHNOLOGY BHOPAL (M. P.) Assignment 2 Properties of Nanomaterials (NT-512) SUBMITTED BY: ANUSHKA UMORYA (24205011101), M. TECH. (NANOTECHNOLOGY) A. Systematically make a record of the evidence...

MAULANA AZAD NATIONAL INSTITUTE OF TECHNOLOGY BHOPAL (M. P.) Assignment 2 Properties of Nanomaterials (NT-512) SUBMITTED BY: ANUSHKA UMORYA (24205011101), M. TECH. (NANOTECHNOLOGY) A. Systematically make a record of the evidence of nanomaterial used in ancient civilizations. Ans. Nanomaterials, defined as materials with structures at the nanoscale (1-100 nanometres), have been discovered in various ancient civilizations, showcasing advanced understanding and application of materials long before modern nanotechnology was formally recognized. Here is a systematic record of such evidence: 1. Ancient Rome: The Lycurgus Cup (4th Century AD) Description: The Lycurgus Cup, dating back to the 4th century AD, is a notable example of dichroic glass, which changes colour depending on the light source. It appears green in reflected light and red when illuminated from behind. Nanoparticle Composition: Analysis using transmission electron microscopy revealed that the cup contains silver-gold alloy nanoparticles (Ag-Au) with diameters between 50-100 nm. These particles are responsible for the cup's unique optical properties, demonstrating an early understanding of nanomaterials Manufacturing Insight: The production of such glass suggests intentional manipulation of materials at the nanoscale, indicating that Roman artisans possessed knowledge akin to modern nanotechnology 2. Ancient Egypt: Black Pigments Application: In ancient Egypt, soot from oil lamps was utilized to create black pigments for writing on papyrus. This soot contains carbon nanoparticles that provide high opacity and stability Significance: The use of these nanoparticles illustrates an early application of nanomaterials in art and documentation. 3. Ancient China: Glazed Pottery (Tang and Song Dynasties) Material: Metallic nanoparticles in glaze. Description: Pottery from these periods has been found with glazes that contain nanostructured metal oxides, giving the pottery a lustrous appearance. Nanotechnology Involvement: The glazes were produced by suspending nanoparticles in the glaze before firing. These nanoparticles produced iridescent effects and unique colour patterns. Significance: This nanomaterial use in pottery showcases the artistic sophistication and the use of metal oxides at the nanoscale. 4. Islamic World and Medieval Europe: Lustre Glazes (9th – 17th Century) Technique: Between the 9th and 17th centuries, artisans in the Islamic world developed iridescent ceramic glazes containing silver or copper nanoparticles. This technique later influenced European pottery during the Renaissance Visual Effects: These glazes produced shimmering effects due to the presence of metallic nanoparticles, showcasing an advanced understanding of materials that enhanced aesthetic qualities. 5. Damascus Steel (13th – 18th Century) Material Properties: During the 13th to 18th centuries, Damascus steel swords were crafted using techniques that involved cementite nanowires and carbon nanotubes. This resulted in blades noted for their exceptional sharpness and resilience. Cultural Impact: The ability to produce such strong materials demonstrates sophisticated metallurgical practices in ancient cultures.  6. Indian Civilization: Keeladi Archaeological Site (2500 years ago) Findings: Archaeological discoveries at Keeladi in India revealed pots dating back 2,500 years that exhibit evidence of manmade nanomaterials. These findings suggest advanced techniques in pottery that included manipulating material properties at the nanoscale. Applications: The application of these nanomaterials might have extended to various aspects of daily life and technology in ancient Indian society. 7. Maya Civilization: Maya Blue (8th -16th Century CE) Material: A vibrant, durable pigment made of indigo, palygorskite (a type of clay), and other minerals. Nanotechnology Involvement: The pigment’s unique durability and resistance to weathering come from the formation of a nanostructured hybrid material. The exact method of mixing and firing these components at low temperatures creates this stable nanomaterial. Significance: Maya Blue was used in murals, pottery, and even human sacrifices, showcasing its cultural and ritual importance. The evidence from these civilizations indicates not only an understanding of materials at a microscopic level but also a deliberate application of these techniques for practical and aesthetic purposes. This historical perspective enriches our understanding of how ancient cultures utilized principles that are now recognized under the umbrella of nanotechnology. B. Prepare a collection and scrapbook with a systematic detail of existence of Nanomaterials in nature. Ans. Nanomaterials abound in the living systems of nature and nanoscientists are examining the properties and potential uses of these natural nanostructures in an area of research called biomimicry. What types of nanostructures are found in nature? They include inorganic materials such as clays, carbonaceous soot (think carbon black), and natural inorganic thin films to a variety of organic nanostructures such as proteins and chitin (insect and crustacean shells) to organic structures such as wing ribs and epidermal projections. These structures lead to a variety of behaviours in nature including the wettability of surfaces, the iridescence of butterfly wings, and the adhesive properties of the gecko foot. Let’s examine a few examples of these biomimetic structures. 1. The Lotus Leaf The Lotus leaf is an example of a surface, which due to the physical and chemical conditions at the micro- and nanometer scale, is able to produce a self-cleaning effect. Wilhelm Barthlott, a German botanist, is considered the discoverer of the Lotus Effect as he applied for its patent in 1994. This effect is the combination of the chemical make-up of the surface and the micro- and nano-projections on the surface. The protrusions are ~10 μm high with each protrusion covered in bumps of a hydrophobic, waxy material that are roughly 100 nm in height. The chitin polymer and epicuticular wax projections allow the leaf to trap air. The water droplets ride on the tips of the projections and resulting bed of air to create a super-hydrophobic surface. Scientists engineered this behaviour with the product Lotusan® - a self- cleaning paint. This paint mimics the microstructure of the surface of a lotus leaf once it dries and cures in the environment. Tiny peaks and valleys on the surface minimize the contact area for water and dirt keeping the surface walls clean. Numerous products are now available that mimic this hydrophobic property including clothing, spray coatings, plungers, bathroom fixtures, automotive parts, etc. 2. The Nepenthes Pitcher Plant: The walls of the Nepenthes pitcher plants are so slick that insects slide down and are digested by juices at the bottom of the bloom. The rim of the plant is completely wettable due to its hydrophilic surface chemistry and surface roughness. These features prevent the insect’s adhesive pads from making contact with the surface causing it to slip down the plant. Think of a car hydroplaning on a wet road or you slipping on an icy surface. Researchers at Harvard University have created similar omniphobic (it is “afraid of” or repels everything) materials that can be used as surfaces for biomedical fluid handling, fuel transport, or as a surface that repels ice thereby reducing energy needs in refrigeration. This Slippery Liquid- Infused Porous Surface (SLIPS) is made of a porous network of Teflon nanofibers that are infused with an oil- and water repelling fluid. 3. Nacre: Nature has evolved complex bottom-up methods for fabricating nanostructured materials that have great mechanical strength and toughness. One of nature’s toughest materials is nacre which is the iridescent mother-of–pearl produced by mollusks. Mollusks create nacre by depositing amorphous calcium carbonate (CaCO3) onto porous layers of polysaccharide chitin. The mineral then crystallizes, producing stacks of CaCO3 that are separated by layers of organic material. Its strength is due to the brick-like assembly (interlocked) of the molecules. Researchers at many universities are synthesizing biomimetic nanocomposites to create strong materials for use in light-weight armour systems, structures in transportation systems, durable electronics, and aerospace applications, among others. 4. Wings of the Morpho butterfly: We all learn that pigments cause the colours that we see but nature has another way of creating colour which we call structural colour. Some insect wings have ordered hexagonal-packed array structures made of chitin. The variety of spacing (from 200 to 1000 nm) between these structures allow wings to serve as antireflective and self-cleaning coatings, provide mechanical strength, improve aerodynamics, and act as a diffraction grating that produces iridescence. Iridescence is the result of the interaction of light with the physical structure of the surface. In the Morpho butterfly, the spaces between the ribs of the wing form natural photonic crystals resulting in the brilliant blue colour. No pigment involved! Researchers are exploring these nanostructures as a means for controlling and manipulating the flow of light - very important in optical communication. In addition, researchers have found that when they coat the Morpho wings with a layer of heat-absorbing carbon nanotubes the shift in reflected wavelength of light can indicate very small temperature changes. These sensors could one day be used to detect inflamed areas in people or points of friction in machines. 5. The Tokay Gecko: The Tokay gecko has interested researchers for a long time because of its ability to cling to smooth surfaces. The gecko foot can adhere to a surface and also release from a surface with ease. Keller Autumn’s study of the foot has shown that it is covered with micro long projections called setae and each setae is covered with thousands of 200 nm long protections. The ability of the gecko to climb along walls and ceilings is due to a combination of these very small nano projections finding minute spaces in the surface in which to adhere due to physical electrostatic forces such as van de Waal forces (intermolecular forces) between the foot and the surface. No glue involved! This study of the gecko foot has led to advancements in adhesives that can be applied and reused. 6. A Moth’s Eye: A moth’s eye has very small bumps on its surface. They have a hexagonal shape and are a few hundred nanometers tall and apart. Because these patterns are smaller than the wavelength of visible light (350- 800nm), the eye surface has a very low reflectance for the visible light so the moth’s eye can absorb more light. The moth can see much better than humans in dim or dark conditions because these nanostructures absorb light very efficiently. In the lab, scientists have used similar man-made nanostructures to enhance the absorption of infra-red light (heat) in a type of power source (a thermo-voltaic cell) to make them more efficient! 7. Spider Webs: Spider webs often appear in the corners of rooms that have not been cleaned for a long time. For ordinary people, cobwebs are not a big deal. With a slight flick, the spider webs are swept away. But spider silk itself is indeed a miracle of nature. Spider silk in nature is about 100 nanometres in diameter, which is a truly pure natural nanofiber. If you use spider silk to make a rope as thick as an ordinary wire rope, it can lift thousands of tons of objects, and its strength is comparable to steel cables. In addition to catching flying insects, almost all spiders also use spider silk as a direction, safety rope, and gliding rope. Spiders usually have several glands on their abdomen, called spinnerets. Various glands produce different types of spider silk. There is a spinneret at the top of the gland, which has thousands of small holes, and the sprayed liquid will condense into cohesive, high-tension spider silk upon encountering air. Spider silk consists of spidroin proteins. Usually, a thousand strands of spider silk are still thinner than 1/10 of a human hair. 8. Serpent Starfish The serpent sea star is a dish-shaped shellfish. It has five tentacles and no eyes. Nevertheless, it can accurately sense potential natural enemies in the distance and retract the tentacles into the shell in time. This sensitive feeling of serpent sea star has long puzzled biologists. Recently, this question has finally found the answer on its carapace: the serpent sea star body is actually covered with “eyes”, that is, tens of thousands of perfect miniature lenses. In this way, the entire furry body constitutes the starfish’s eyes. Studies also show that the number of such lenses on a serpent sea star is about 50,000 to 100,000, and they are composed of calcium carbonate nanocrystals; this perfect light-sensitive micro-lens system is the result of nano-crystallization on the surface of the starfish’s body growth. In order to prevent unnecessary color  fringing, a proper amount of magnesium is also absorbed in the lens during crystallization, which can not only help starfish filter the light more effectively but also correct the “spherical aberration” of the lens. This improves the efficiency of finding natural enemies. We know that nature can produce many complex nanoscale structures and now researchers are exploring the natural world to learn its nanoscale secrets. They are using nature as a model for manufacturing these same complex structures. Nanotechnology can and will be used to enhance hundreds of products many of which we interact with in our daily lives. As this research using nature continues, there will be many more breakthroughs that will lead to new devices and materials that will impact many aspects of society.