JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B. Pharmacy IV NANO TECHNOLOGY Previous Question Paper (July/August-2022 - R17)

Nanotechnology is the branch of science and engineering that involves the design, production, and manipulation of materials, structures, and devices at the nanoscale, typically ranging from 1 to 100 nanometers. At this scale, materials exhibit novel physical, chemical, and biological properties that differ significantly from their bulk counterparts due to increased surface area and quantum confinement effects.

The unique properties of nanomaterials arise primarily from two factors: the surface-to-volume ratio and quantum effects. Key properties include:

1. Surface Properties: As particle size decreases, the percentage of atoms located on the surface increases dramatically. This leads to higher surface energy and increased chemical reactivity, making nanomaterials excellent catalysts and sensors.
2. Optical Properties: Nanomaterials often exhibit size-dependent optical behavior. For example, gold nanoparticles change color from red to blue depending on their size and shape due to surface plasmon resonance, which is not observed in bulk gold.
3. Mechanical Properties: Many nanomaterials demonstrate superior strength and hardness compared to bulk materials. Carbon nanotubes, for instance, possess an exceptionally high strength-to-weight ratio due to their unique atomic bonding and structural integrity.
4. Electrical and Magnetic Properties: At the nanoscale, materials can transition from insulators to conductors or exhibit superparamagnetism. Quantum confinement restricts the movement of electrons, leading to discrete energy levels that allow for the development of quantum dots and specialized electronic components.
5. Thermal Properties: Nanomaterials often show altered thermal conductivity. While some exhibit enhanced heat transfer capabilities, others act as thermal insulators due to phonon scattering at grain boundaries.

The concept of nanotechnology originated from the visionary lecture titled There's Plenty of Room at the Bottom, delivered by physicist Richard Feynman at the American Physical Society meeting in 1959. Feynman proposed the possibility of manipulating individual atoms and molecules to create materials and devices with unprecedented properties, effectively laying the theoretical foundation for the field.

The term nanotechnology was later coined by Norio Taniguchi in 1974, who defined it as the processing, separation, consolidation, and deformation of materials by one atom or one molecule. This provided a formal nomenclature for the field that was previously only conceptual.

The field gained significant momentum in the 1980s through several key milestones:

• 1981: The invention of the Scanning Tunneling Microscope (STM) by Gerd Binnig and Heinrich Rohrer at IBM allowed scientists to visualize and manipulate individual atoms for the first time.
• 1985: The discovery of fullerenes (C60 or buckyballs) by Harold Kroto, Robert Curl, and Richard Smalley opened a new era in carbon-based nanomaterials.
• 1986: K. Eric Drexler published Engines of Creation, which popularized the concept of molecular nanotechnology and self-replicating nanomachines, bringing the field into the public consciousness.

In the 1990s, the discovery of carbon nanotubes by Sumio Iijima further accelerated research into high-strength, conductive nanomaterials. By the early 2000s, nanotechnology transitioned from purely academic research to industrial application, marked by the establishment of the National Nanotechnology Initiative (NNI) in the United States in 2000, which catalyzed global investment and interdisciplinary collaboration.

Today, the history of nanotechnology is defined by its evolution from a theoretical curiosity into a multidisciplinary science integrating chemistry, physics, biology, and engineering to revolutionize sectors such as medicine, electronics, energy, and environmental remediation.