What is Graphene?

  • Graphene is an allotrope of carbon, alongside diamond and graphite.
  • It consists of a single layer of carbon atoms arranged in a honeycomb pattern.

Known for its exceptional properties:

  • Thinnest compound (one atom thick)
  • Lightest material
  • Strongest compound discovered (between 100-300 times stronger than steel)
  • Best conductor of heat at room temperature
  • Best conductor of electricity known
  • Almost perfectly transparent as it absorbs only 2% of light.
  • Impermeable to gases, even those as light as hydrogen and helium.
  • Stronger than diamond.
  • More conductive than silver.
  • More elastic than rubber.
  • Lighter than aluminium.

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  • Flexible Electronics: Graphene’s flexibility and transparency make it suitable for flexible electronic devices. It can be used in wearable electronics, flexible displays, electronic textiles, and bendable sensors. 
  • Energy Storage: Graphene-based materials can enhance the performance and capacity of energy storage systems while reducing charging time. Ideal to create supercapacitors and high-performance batteries.
  • Water purification: Graphene oxide membranes have nanometer-sized pores that enable selective permeability, which allows passage of water molecules while blocking the passage of ions, salts, and larger molecules. This property makes them suitable for water filtration systems and desalination systems. E.g., Removing pesticides from water. 
  • Biosensors: Graphene can be used to sense chemical and biological agents, explosives, radiation, and other hazardous substances. E.g., Graphene-based sensors can detect CO2 and volatile organic compounds inside buildings with significantly low power usage. 
  • Aerospace and Defense: Graphene’s remarkable strength-to-weight ratio makes it an attractive material in the Aerospace sector for developing lightweight and high-strength armour and ballistic protection. E.g., Create lighter impact-resistant helicopter and aircraft structures. Graphene has the potential to absorb and dissipate electromagnetic waves, making it valuable for developing stealth coatings and materials that reduce radar signatures and electromagnetic interference. 
  • Medical Applications: Biomedical applications of graphene-based nanomaterials include biosensing, bioimaging, targeted drug delivery, tissue engineering, phototherapy and cancer treatment. 
  • Other industrial usages: Used as waterproof coatings for industrial machinery, ocean liners, and aircraft. Graphene oxide-based wrappers loaded with preservatives can increase the shelf life of fruits and vegetables. Strengthening car tires, replacing silicon in smartphone chips. Enhancing concrete strength by 25% and reducing carbon intensity.

Unusual Properties:

  • In 2019, for example, physicists found that when one sheet of graphene is placed above another and rotated by 1.1 degrees relative to the bottom layer, the stack becomes a superconductor at low temperature.

Practice question:

Q. With reference to graphene, consider the following statements:

1. It is a single carbon allotrope organised in a honeycomb pattern.

2. It has the potential to become a superconductor at high temperatures.

3. It is more elastic than rubber.

How many of the statements given above are correct?

(a) Only one

(b) Only two

(c) All three

(d) None of the above

Ans: (b) 

Previous year question (2020)

Q. With reference to carbon nanotubes, consider the following statement:

1. They can be used as earners of drugs and antigens in the human body.

2. They can be made into artificial blood capillaries for an injured part of the human body.

3. They can be used in biochemical sensors.

4. Carbon nanotubes are biodegradable.

Which of the statements given above are correct?

(a) 1 and 2 only

(b) 2, 3 and 4 only

(c) 1, 3 and 4 only

(d) 1, 2, 3 and 4

Ans: (c)

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