Nanotechnology: a mini world

INTRODUCTION

Nanotechnology refers to science and technology whose unifying theme is the control of matter on the atomic and molecular scale, normally 1 to 100 nanometres, and the fabrication of devices with critical dimensions that lie within that size range. A basic definition of nanotechnology is the engineering of functional systems at the molecular state. This covers both current work and concepts that are more advanced. In its original sense, ‘nanotechnology’ refers to the projected ability to construct items from the bottom up, using techniques and tools being developed today to make complete, high performance products. Nanotechnology is the science of building machines at a subatomic level.

Manufactured products are made from atoms. The properties of those products depend on how those atoms are arranged. If we rearrange the atoms in coal, we get diamonds. If we rearrange the atoms in sand (and add a pinch of impurities) we get computer chips. If we rearrange the atoms in dirt, water and air, we get grass. Since we first made stone tools and flint knives we have been arranging atoms in thundering statistical heards by casting, milling, grinding, chipping and the like. We’ve gotten even better at it: we can make more things at lower cost and greater precision than ever before. But at the molecular scale we’re still making great ungainly heaps and untidy piles of atoms.

Thus one of the basic principles of nanotechnology is positional control. The ability of chemists to synthesize what they want by stirring things together is truly remarkable. Imagine building a radio by putting all the parts in a bag, shaking, and pulling out a radio – fully assembled and ready to work! Self assembly – the art and science of arranging conditions so that the parts themselves spontaneously assemble into the desired structure is a well established and powerful method of synthesizing complex molecular structures. A basic principle in self-assembly is selective stickiness: if two molecular parts have complementary shapes and charge patterns – one part has a hollow where the other part has a bump, and one part has a positive charge where the other part has a negative charge. Then they will tend to stick together in one particular way. By shaking these parts around, something which thermal noise does for us quite naturally if the parts are floating in a solution, the parts will eventually be, purely by chance, brought together in just the right way and combine together into a bigger part. This bigger part can combine in the same way with other parts, letting us gradually build a complex whole from molecular pieces by stirring them together and shaking.

General-Purpose Technology

Nanotechnology is sometimes referred to as general-purpose technology. That’s because, in its advanced form it will have significant impact on almost all industries and all areas of society. It will offer better built, longer lasting, cleaner, safer and smarter products for the home, for communications, for medicine, for transportation, for agriculture, and for industry in general.

Dual-Use Technology

Like electricity or computers before it, nanotechnology will offer greatly improved efficiency in almost every facet of life. But as general-purpose technology, it will be dual-use, meaning it will have many commercial uses and it will also have many military uses – making far more powerful weapons and tools of surveillance. Thus, it represents not only wonderful benefits for humanity, but also grave risks.

Products with Nanotechnology

When light hits the glass, nanoparticles become energized and begin to break down and loosen organic molecules on the glass (in other words, dirt). Hydrophilic substance means that when water makes contact with the substance’s surface, it spreads on it, like glass. You might be surprised to find out how many products in the market are already benefiting from nanotechnology.

• Sunscreen – Many sunscreens contain nanoparticles of zinc oxide or titanium oxide. Older sunscreen formulae used larger particles, which is what gives most sunscreens their whitish colour. Smaller particles are less visible, meaning that when you rub the sunscreen into your skin, it doesn’t give you a whitish tinge.
• Self-Cleaning Glass – A company called Pilkington offers a product they call Activ Glass, which uses nanoparticles to make the glass photo-catalytic and hydrophilic. The photo-catalytic effect means that when UV radiation crosses the glass evenly, which helps wash the glass clean.
• Clothing – Scientists are using nanoparticles to enhance your clothing. By coating fabrics with a thin layer of Zinc Oxide nanoparticles, manufacturers can create clothes that give better protection from UV radiation. Some clothes have nanoparticles in the form of little hairs or whiskers that help repel water and other materials, making the cloth stain-resistant.
• Scratch-Resistant – Engineers discovered that adding Aluminium Silicate nanoparticles to scratch-resistant polymer coatings made the coating more effective, increasing resistance to chipping and scratching. Scratch-resistant coatings are common on everything from cars to eye-glass lenses.
• Anti-microbial Bandages – Scientist Robert Burrell created a process to manufacture antibacterial bandages using nanoparticles of Silver. Silver ions block microbes’ cellular respiration. In other words, Silver smothers harmful cells, killing them.
• Swimming pool cleaners / Disinfectants – EnviroSystems, Inc. developed a mixture (called Nano-emulsion) of nano-sized oil drops mixed with a bactericide. The oil particles adhere to bacteria, making the delivery of the bactericide more efficient and effective.

Conclusion

Here’s an unprecedented multidisciplinary convergence of scientists dedicated to the study of a world so small, we can’t see it – even with a light microscope. That world is the field of nanotechnology, the realm of atoms and nanostructures. Is nanotechnology the impetus for the next Industrial Revolution?

 

I want to build a billion tiny factories, models of each other, which are manufacturing simultaneously… The principles of Physics, as far as I can see, do not speak against the possibility of manoeuvring things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done, but in practice, it has not been done because we are too big. – Richard Feynman, Nobel Prize winner in Physics

Imagine a medical device that travels through the human body to seek out and destroy small clusters of cancerous cells before they can spread; or a box no larger than a sugar cube that contains the entire contents of The Library of Congress; or a material much lighter than steel that possess ten times as much the strength. – U.S. National Science Foundation