What are Nanomaterials?

Nanomaterials are materials that are composed of nanoparticles having a size ranging from 1 to 100 nm. The constituent particles are 100,000 times smaller than the thickness of a strand of human hair. The nanoparticles cannot be seen through naked eyes and require very high-resolution microscopes. Here, 'nm' stands for nanometer. These materials can occur naturally or can be artificially made. Artificially made nanomaterials are often called lab-engineered nanomaterials. Nanomaterials are extensively used in electronics, medical, aerospace, and other industries.

Applications

The study of nanomaterials and nanoparticles primarily falls under the branch of science known as nanotechnology. It deals with the study of science related to chemical, thermal, mechanical, and biological processes at the nanoscale level. For instance, Sir Richard Feynman is considered to be the father of nanotechnology. The idea of nanotechnology began from a talk presented by Sir Richard Feynman, who explained the possibility to control individual atoms, molecules governing many biological and chemical processes. A decade later, after the talk, Professor Norio Taniguchi named the area 'nanotechnology' while he was experimenting with ultra precession machining and its scope and applications.

To study different cutting edge and exciting researches based on nanomaterials, one can refer plethora of scientific articles on nano-research, and various peer-reviewed journals such as ACS Nano.

Occurrence of Nanomaterials

Nanomaterials can be naturally found in humans, living bodies, and many biological processes that constitute nanomaterials. The proteins found in blood are made up of nanomaterials, and body lipids are made up of nanomaterials. Ash produced by a volcanic eruption, fine sand, dust, and micro-organisms such as viruses constitutes nanoparticles. The use of silicon nanoparticles for the development of solar cells is currently under research. These solar cells would have the ability to trap solar energy by specially engineered nano-sized particles.

Apart from these lab-engineered nanomaterials can be found in day-to-day products such as cosmetic products, sports equipment, clothing that are stain-resistant, electronic gadgets, and so on.

Use of Nanomaterials

There are huge applications of nanoparticles in different sectors such as medical, automobiles, textile, and others. Some of them are discussed below.

Nano-particle based electronics devices

There are numerous uses of nanoparticles in the electronics industry. In the present era, all semiconductor chips are manufactured using single-walled carbon nanotubes. The primary use of these single-walled carbon nanotubes can be found in photovoltaic applications. A variety of nanomaterials are used in lighting technology such as light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs). A majority of laser implementing devices make up the quantum dot technology. A variety of lithium-ion batteries make use of nanoparticle-based compositions that are used by the majority of communication devices. Extensive nanotechnology-based research is underway to develop lead-free solders which could be potentially less dangerous to human health. Apart from these, many nanoparticles are used in making surface coatings in different electronic equipments.

Nanoparticles in medicine

The chemical behavior of bulk materials composed of nanoparticles is different from that of a material composed of ordinary micro-sized particles. The nanoparticles used in photodynamic therapy are used for safe imaging of internal organs. Moreover, photodynamic therapy can be used for imaging delicate living tissues, and infected tissues in human bodies. The medical sector has been into large-scale development of nanoparticle-based therapeutic agents that have been widely used in cancer therapy, asthma, and allergic treatments.

Nanoparticle-based biomedical applications

Recently, carbon-based nanoparticles in biomedical applications have attracted researchers from all around the globe. These materials have unique chemical, thermal, and mechanical properties. For instance, these materials have an extensive application in making biosensors, drug delivery systems, and cancer therapy. Carbon nanoparticle, such as graphene oxide, plays a major role in biomedical drug delivery systems.

Nano polymer technology

The use of this technology has helped in developing surface sealants, paints, adhesives, and coatings for different applications.

Properties of Nanomaterials

Self-assembling

Individual nanoparticles are combined in orderly orientations to form nano-structures or patterns. It is due to the physical attraction among the nanoparticles that imparts the property of self-assembling within nanoparticles. For instance, the formation of nanostructures such as micelles, vesicles, and hydrogels is due to the property of self-assembling.

Self-cleaning

Advancements in the development of self-cleaning glass are a major area of research. This kind of glass is generally used for outdoor purposes. During the glass manufacturing process, a UV-resistant titanium oxide film is coated to the glass surface. When sunlight falls on the glass surface, the UV radiation decomposes the organic dirt on the glass surface. This reduces the frequent cleaning of the glass surface. However, the cleaning is size-dependent. The UV treatment makes the glass hydrophilic that attracts water molecules. The more is the surface area of glass, the more cleaning is required for water droplets.

Context and Applications

The topic has extensive scope for research and development. The topic is taught in the subject of materials science in undergraduate and postgraduate curriculums. The topic finds its existence in

• Bachelor of Nano-science
• Bachelors in Nano-technology
• Masters in Nano-technology

Practice Problems

1. In which of the following medical applications, nanomaterials are widely used?

1. Cancer therapy
2. Biomedical applications
3. Organ imaging
4. All of these

Correct option- d

Explanation: Nanomaterials are primarily used in many applications such as cancer therapy, biomedical applications, and organic imaging of the interiors of a living body.

2. Which of the following nanoparticles is used in the drug delivery system?

1. Graphene oxide
2. Nanocrystalline materials
3. Silicon dioxide
4. Polymer-based substances

Correct option- a

Explanation: Graphene oxide is extensively used as a nanoparticle for drug delivery system

3. In which of the following medical applications, nanotechnology is used?

1. ACS Nano
2. Cancer therapy
3. Diabetes detection devices
4. Biological imaging applications

Correct option: Both b and c

Explanations: Nanotechnology has a wide area of applications in the medical area such as in cancer therapy, diabetes detection devices, in the biological imaging process, and so on.

4. Which of the following is a property of nanomaterial?

1. Self-cleaning
2. Self-assembling
3. Self-illuminating
4. None of these

Correct option: Both a and b

Explanation: Nanomaterial has the property of self-assembling and self-cleaning.

5. In which electronic applications are nanoparticles used?

1. OLED lights
2. Resistors
3. Capacitors
4. Thermistors

Correct options- a

Explanation: Nanoparticles are used in organic light-emitting diodes (OLED), which are used for lighting purposes.