Nanotechnology: A Brief Note 2024 | EKADEMY | Online Courses, Live Classes, Lessons & Quizzes

A brief note on Nanotechnology

Introduction

Nanotechnology is the understanding and control of matter at the nanoscale (1nm to 100nm).
Matter exhibits unique/unusual chemical, physical and biological properties at the nanoscale which are very different from the bulk materials (macro scale).
For example, nanomaterials

can have unique magnetic properties,
they can be a better conductor of electricity,
can be more chemically reactive, or
can change colour as their size or structure is altered.
At the nano-scale number of atoms/molecules is very low and hence they can be manipulated/altered.
If we can perform such manipulations at the nanoscale much different materials can be created with huge potentials and varying properties.
For example, Gold at the nanoscale will have different chemical and physical properties than that at the macro/bulk level.
Also, the properties of nanomaterials are a function of size itself, ie properties of nano-material change as their size changes.

For example, nano gold at 100 nm will show different properties than nano gold at 20 nm.
The properties may include magnetic properties, different conductivity, more chemically reactive, and better reflectors of light or colour.

Why is nanoscale so significant?

At nanoscales quantum effects dominate.
At such a scale surface behavior plays a very important role as nanomaterials have a very high surface area.
Much of the biology occurs at the nanoscale. For example, DNA molecules have a 2 nm diameter, similarly, Hemoglobin has a 5 nm diameter.

Nanomanufacturing

There are two ways to manufacture nanomaterials:

A. Top-Down Approach

It involves breaking down bulk materials into nano-sized particles.
Many lithographic techniques such as electron beam lithography, and high-energy milling use a top-down approach.

B. Bottom-Up Approach

Where nanomaterials are built atom by atom, molecule by molecule.
A few of these techniques are colloidal precipitation, hydrothermal synthesis, etc.

Generations of Nanotechnology

Nanotechnology is divided mainly into four generations which also gives a road map for the future of nanotechnology.

1. First-generation or Passive Nanomaterials.

These materials provide unique properties without altering the properties of the surroundings. e.g. nano-coating.

2. Second-generation or Active Nanomaterials.

These nanomaterials can induce changes in their surroundings thus they have huge applications, for example, targeted drug delivery.

3. Third generation or System of Nano-system

Here nanoparticles and nano-materials will work together to execute the task.
Complex systems such as guided assembling, nanorobotics, etc.

4. Fourth-generation or Molecular Nano-system

At this level, all the molecules that make up the nanomachine can be controlled and manipulated.
This is the potential of nanomaterial yet to be realized where nanostructure can be used to control the growth of artificial organs.
The 3^rd & 4^th generation nanotechnology is still in the exploratory stage.
A lot of work is happening in the 1^st & 2^nd generations of nanotechnology.

Applications of Nanotechnology

Nanotechnology has enormous applications in various fields like health care, environment, agriculture, electronics and others. We will try to explore some of its applications below:

A. In daily life:

Fabrics: nanoscale additives can help fabrics in resisting wrinkling, staining, and even bacterial growth.
Nano-sensors can be used in clothes they can help to measure the vitals of the body and help monitor health.
Glasses and displays: Nano-scale films are used in eyeglasses, computers, camera displays, and others making them water-repellent, self-cleaning, scratch-resistant, etc.
Lightweighting: Nano additives are being used in automobiles, aeroplanes, and spacecraft that reduce their weight without compromising the material’s properties. This leads to significant fuel savings.
Cosmetics: Nanoscale Titanium Dioxide is used in sunscreen lotions to protect from sun rays.

B. Medical & healthcare applications:

Cancer treatment: Gold nanoparticles are being investigated as potential treatments for cancer.
Targeted drug delivery: nanoparticles can help deliver medication directly to the diseased cells and minimize the risk of damage to healthy tissues.
Disease Diagnosis: better imaging and tools enabled by nanotechnology.
Tissue Engineering: Some nanomaterials have regenerative medicinal properties which can be used in tissue engineering.
Killing Superbugs: Nanotechnology may hold the key to ending/fighting antimicrobial resistance.

C. In electronics:

Transistors have gotten smaller and smaller through nanotechnology.
Quantum dots-based displays produce more vibrant colours than other display technologies.
Flexible & foldable displays are, memory chips for smartphones, etc also use nanotechnology.

D. Environmental Application:

Nanomembranes are used in water filtration.
Certain nanoparticles are being developed to clean industrial pollutants.
Magnetic water-repellent nanoparticles help remove oil from the water.

E. In Agriculture:

Nano formulations of agrochemicals for applying fertilizer and pesticides for crop improvement.
Nanodevices for the genetic engineering of plants.
Diagnosis of plant diseases using nanotechnology.
Management of animal health and animal breeding.
Precision farming techniques using nanotechnology to improve crop yields without damaging the soil.

Issues or challenges of nanotechnology

Some doctors worry that the nanoparticles can cross the blood-brain barrier because of their size.
Nanotechnology enables the development of powerful lethal weapons.
They can enter the food chain and can lead to bioaccumulation and biomagnification.
They can enter the human body and because of high chemical reactivity can produce toxins inside the body.
If not handled properly they can create significant damage to a larger area because of their boundary-crossing nature.

Nanotechnology in India

A dedicated Mission called Nano Mission also as National Mission on Nanotechnology was launched in the 11th FY Plan.
It was extended in the 12th FYP.
It was completed in the year 2020.
India stands third in research papers publication after the USA and China.
But the quality of these papers is not up to the mark.
Also, the Industry-Academia linkage is not adequate due to which we are not able to see the impacts of R&D on the ground.

Carbon Nanotube and Quantum Dots

Graphene is an allotrope of carbon which is a single layer of carbon atoms arranged in a hexagonal structure.
It is the same as a single layer of graphite.
It is a good conductor of electricity, has high tensile strength, is much lighter, and has other useful characteristics.

Carbon Nanotube

It is created by the folding of graphene sheets.
Based on folding patterns and orientation the carbon nanotubes have varying characteristics.
Apart from the characteristics of graphene, they have some other useful characteristics based on their folding patterns.
They are chemically very stable; they do not react to anything easily.
Their hollow can also be used to store other nanomaterials. Storage of Liquid Hydrogen in carbon nanotubes is being explored.
They can be used for targeted drug delivery.

Quantum Dots

These are nano-sized semiconductors.
Just by changing their size, the emitted light can be of different colours despite having the same materials and the same frequency/colour of incident light.
They are used in manufacturing QLED displays, which use less electrical energy.
They are used to harness solar energy in photovoltaic cells.
They are also used to kill superbugs (anti-microbial-resistant microbes).
The Nobel Prize in Chemistry 2023 was awarded to
- Moungi Bawendi, Louis Brus and Aleksey Yekimov
- for the discovery and synthesis of quantum dots.
Yekimov and Brus independently succeeded in creating quantum dots
Bawendi revolutionised the chemical production of Quantum Dots.