A brief foray into the world of

Nanomaterials

Dr. Sarbari BhattacharyaDept. of Physics

Bangalore University

kilo = 103 = 10001 kilogram = 1000 gramsmilli = 10-3 = 1/10001 millilitre = one thousandth of a litrenano = 10-9 = 1/10000000001 nanometer = 1 billionth of a metre

What does the term ‘nano’ denote ?

Nanomaterial => at least one dimension < 100nm

Categorization of nanomaterials 1d 2d 3d confinedEg: Quantum Wells Nanowires Nanoparticles Bucky Balls

What are the reasons behind the difference in properties of nanomaterials and bulk materials ?

• Energy considerations

Why is a dedicated study of such materials warranted ?

Schematic energy band structure of a bulk semiconductorH atom energy levels

An analogy:The water tank – material large tank – bulk material confined tank – nanomaterialWater – energy of the system

Eg : the colour of Gold Nanoparticles

•Change in surface to volume ratio

Analogy: alveoli in the lungs

Magnetic Nanoparticles

Bulk ferromagnetic domain structure

Bulk FerromagnetSuperparamagne

ticNanoparticle

Some Application Potentials: • Information data storage

Possible with self assembled nanomagnets eg: FePt

Binary information storedin terms of direction of magnetization of the nanomagnets

1 0 0 1 0 1

•Targeted Drug Delivery1. Size close to that of most biological entities of interest2. Can be controlled by an external magnetic field

Superparamagnetic nanoparticles being delivered in aerosols (green). A localized magnetic field causes large numbers of nanoparticles to accumulate in a specific region, shown here in red.

Novel approach for the local treatment ofarthritis or osteoarthritis using magnetically retainable drug delivery systems

Conclusion : Unique properties of nanomaterials have lend themselves to an enormous range of applications. The set keeps on increasing day to day. In fact, one has probably only just started … !!!

From the following articleNanomedicine: Magnetic nanoparticles hit the target

Alidad AmirfazliNature Nanotechnology 2, 467 - 468 (2007) Published online: 22 July 2007doi:10.1038/nnano.2007.234BACK TO ARTICLESuperparamagnetic nanoparticles are placed in microdroplet aerosols (green) and delivered along the airways (brown) toward the lungs (grey). A localized magnetic field causes large numbers of nanoparticles to accumulate in a specific region, shown here in red.Figures and tables index BACK TO ARTICLE

Bohr atomic model