Navid B. Saleh

The Daily Star

Publication Date : 14-01-2013

Since the inception of the new millennium, scientists have embarked on an exciting journey of developing novel materials with unique properties that are revolutionising the world around us. Chemical manipulation at the nano-scale -- that is at a linear scale equivalent to a billionth of a metre -- has allowed to alter, enhance and incorporate physical and chemical material-properties. Such innovations have generated new materials improving the products, devices, and processes of immense commercial and scientific importance; for example, transparent catalysts for touch-screen devices, high-efficiency semiconductors for solar cells, core-shell particles for deliverable and release-controlled drugs, heat-conductive materials for cancer therapy, reactive agents for environmental cleanup, etc. Such promises of nanotechnology emanate from its ability to crosscut disciplinary boundaries and its ability to be applied to any field, which desires improved material properties for better efficiency and performance. Thus, many developing countries, which are otherwise not heavily involved in technology development, are entering a phase of technological competitiveness using this interdisciplinary field of nano-scale science. Leaving Bangladesh, a leading nation in the "Next 11", out of this race seems to be unwise. This article will introduce fundamental and applied aspects of nanotechnology and will discuss the promises of this technology for Bangladesh.

Nanotechnology is founded on material manipulation at the nano-scale, where at least one dimension of the material is sized between 1 and 100 nanometres. Its scale aspect can be facilitated by comparing between the sizes of the earth, a soccer ball and a nanoparticle; that is, the ratio of the earth's diameter and the diameter of a soccer ball, roughly equals the ratio of the diameters of a soccer ball and a nanoparticle. In defining a nanomaterial, it is imperative to identify that the material of concern has uniquely different properties at the nano-scale compared to its larger scalar forms. Since nano-scale materials are sub-microscopic, that is, cannot be observed even with high powered optical microscope, the development of this field required advances in electron microscopy; which was introduced in 1981 via introduction of scanning tunneling microscopy (STM).Though the fundamental concepts of nanotechnology was discussed by Nobel laureate Richard Feynman in 1950s, the first nanomaterial development and identification occurred in mid 1980s through the all-carbon fullerene's discovery by Nobel laureates Harry Kroto, Richard Smalley, and Robert Curl. Later on, tubular fullerenes or carbon nanotubes' incidental discovery by Sumio Iijima in 1991 advanced the field of nanotechnology a bit further. Though the initial development of nanomaterials started with carbon-only structures, scientists have utilised many of the metals and other non-metals as core elements to engineer novel nanomaterials. The singular nanomaterial synthesis and characterisation has flourished since the latter half of the 1990's decade. These materials are used in various applications till today. However, the current focus in this field has shifted towards conjugation of multiple nanomaterials to form hierarchical structures with the intent to extract multi-functionality from a single engineered material. The field of nanoscience and nanotechnology has passed its infancy and is now gaining pace aided by the global economic turnaround. It is high time to ride this 'technological wave' before it is too late for us to join in as a competitive force in research, development, or application of nanotechnology.

It is probably well perceived by now that nanomaterials possess sub-microscopic size that gives added material-advantage. But, what are these advantages and why are these manifested at this scale? Here, the two most profound nano-scale effects are discussed in brief. As a material is sized down, the effective surface area of the material expands, providing more room to perform novel physics, chemistry, and biology. Consider a simple example: a loaf of bread has a total of six sides; if the loaf is sliced in half, the total volume of the bread remains the same, however, number of sides increases by two (along the length of the cut). If the loaf is sliced in four equal squares, eight new surfaces will emerge from the same volume of material. This is how, sizing down a material continues to increase exposed surfaces and allows scientists to incorporate more functional entities on the newly exposed planes. The second manifestation is known as "quantum effects". Gold nanomaterials demonstrate such unique effects at this scale: gold is commonly identified with shiny yellow colour at macroscopic level; however, at the nano-scale the colour of gold changes to red or purple, due to quantum confinement. The optical properties, for example, colour of a material originates from electronic vibration of molecules or collective phonons or lattice modes. The vibrational frequency of the electrons is identified with either a visible colour or remains undetected as invisible infrared or ultraviolet radiation. At macro-scale, electron movement on or through the gold lattices encounters more freedom yielding the yellow coloured appearance of the material; which is compromised at the nano-scale due to quantum confinement issues. The change in electron vibration is reflected via change in colour of the gold nanoparticles that are effectively utilised in medical imaging. Similarly, quantum effects alterreactive, electromagnetic, and biological properties of a material and can be effectively utilised for various applications.

Unique material attributes mentioned earlier are utilised in many applications that include: electronics, energy applications, sensors, drug delivery, therapeutics, etc. Can Bangladesh take advantage of this novel technology? The immediate reaction will likely be a loud and resounding "NO". General public perception in our country for advanced technologies is that these are too high-tech for a developing country like Bangladesh.

We cannot afford to spend time and resources on such endeavours when basic needs for many are not met. In presenting this argument we forget that our economy has traditionally relied on agriculture and recently on garment sector to drive the economic engine. We merely have any competitive advantage in industrial sector other than cheap labour. Other countries such as India, Sri Lanka, Vietnam and the Philippines are already trumping us on this argument. Many of the aforementioned countries realise that cheap labour advantage is going to be short-lived and have already begun a concerted and focused effort in nano-technological development. Why and how is that possible? It may appear that nanotechnology will require expensive equipment and ultra-clean facilities to pursue research and development. It is mostly true for nano-electronic sector and probably that is why none of these countries have chosen nano-electronics as their focus area. Many nanomaterials can easily be synthesised via wet-chemical processes which are simple to perform and can be pursued anywhere. Using such techniques and following the path showed by countries like India or the Philippines, we can pursue nano-scale research and development with a focused effort: may be on agricultural, pharmaceuticals, garment industry, or cement products. The research focus can utilise wet-chemistry, where the identification and characterisation of nanomaterials can be done using already existing imaging facilities at the Dhaka centre of our Atomic Energy Commission. The industrial wing on the other hand can pursue collaboration, where international patents can be used to manufacture products related to the focus industries. One of the first efforts, however, should be establishing academic training programmes that will develop a trained professional class, serving as a competitive advantage to attract international business.

This article has hopefully introduced fundamentals of nanotechnology and demonstrated its advantages. It is imperative that Bangladesh should begin to transform itself from a mere consumer to a product/device manufacturer; nanotechnology can provide this kick-start. The efforts should be focused and well planned and should utilise the existing infrastructure and strength that Bangladesh possesses. I believe that Bangladesh can curve a strong scientific mark in the international arena using nanotechnology and its brilliant younger generation as essential vehicles.

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Promises of nanotechnology for Bangladesh