Modern materials and nanotechnology

This page covers one Form 5 content standard from the Consumer and Industrial Chemistry chapter: modern materials and nanotechnology. The exam expects you to name modern materials with their special property and a use, to explain what nanotechnology is and why nanoparticles behave differently, and to give the benefits and concerns of using them. Treat this like the other applied standards: material → property → use, plus a balanced evaluation.

Modern materials and their uses

Modern materials are substances developed for special properties. Learn each as material → property → use:

• Superconductors, have zero (or almost zero) electrical resistance below a certain low temperature, so they carry current with no energy loss. Uses: powerful electromagnets in MRI scanners and magnetic-levitation (maglev) trains.
• Fibre optics, thin glass fibres that carry information as pulses of light. Uses: high-speed telecommunications and internet cables, and in medical instruments to see inside the body.
• Liquid crystals, substances that change how they reflect or transmit light when conditions change. Uses: LCD screens in calculators, watches, phones and televisions.
• Semiconductors, conduct electricity better than insulators but less than metals, and their conduction can be controlled. Uses: the transistors and microchips in every electronic device.
• Advanced (fine) ceramics, hard, heat-resistant and chemically stable. Uses: cutting tools, engine parts and electronic components.
• Photochromic glass, darkens in bright light and clears in dim light. Uses: light-sensitive spectacle lenses.

What nanotechnology is

Nanotechnology is the science and technology of making and using materials at the nanoscale, structures roughly 1 to 100 nanometres (nm) in size, where 1 nm = 1 × 10⁻⁹ m. At this scale a material can behave very differently from the same material in bulk.

The key reason is the surface-area-to-volume ratio. As particles get smaller, a much larger fraction of their atoms sit on the surface, so the surface-area-to-volume ratio becomes very large. This makes nanoparticles more reactive and can give them new optical, electrical and mechanical properties.

Uses of nanotechnology

• Nanoparticles in sunscreen, titanium dioxide and zinc oxide nanoparticles block ultraviolet light while looking transparent on the skin.
• Carbon nanotubes, extremely strong yet light and able to conduct electricity; used to strengthen sports equipment and in electronics.
• Self-cleaning and stain-resistant surfaces, nanocoatings on glass and fabrics repel water and dirt.
• Targeted drug delivery, nanoparticles can carry a medicine to a specific part of the body.
• Smaller, faster electronics, nanoscale components allow more powerful, compact devices.

Concerns about nanotechnology

A balanced answer also gives the concerns. The health and environmental effects of nanoparticles are not yet fully understood, because they are so small, they may enter the body or the environment in ways larger particles cannot. So nanomaterials should be researched, tested and regulated carefully. Avoid saying nanotechnology is simply “good” or “bad”; the marks are in giving a benefit and a concern.

Worked example

Question. A nanoparticle is modelled as a cube of side 10 nm. (a) Express this side length in metres. (b) Calculate its surface-area-to-volume ratio, and compare it with a larger cube of side 1000 nm of the same material.

Step 1, Convert the side to metres. 10 nm = 10 × 10⁻⁹ m = 1 × 10⁻⁸ m.

Step 2, Write the ratio for a cube. A cube of side a has surface area 6a² and volume a³, so surface-area-to-volume ratio = 6a² ÷ a³ = 6 ÷ a.

Step 3, Calculate for each cube. For the nanoparticle: 6 ÷ 10 nm = 0.6 nm⁻¹. For the larger cube: 6 ÷ 1000 nm = 0.006 nm⁻¹.

Step 4, Compare. 0.6 ÷ 0.006 = 100, so the nanoparticle has a surface-area-to-volume ratio 100 times larger than the larger cube.

Answer. (a) The side is 1 × 10⁻⁸ m. (b) The nanoparticle’s ratio is 0.6 nm⁻¹, one hundred times greater than the larger cube’s 0.006 nm⁻¹, which is why nanoparticles are so much more reactive.

Practice question

Question. (a) Name one modern material used in fast telecommunications and state the property that makes it suitable. (b) State what is meant by nanotechnology, including the size range involved. (c) Give one benefit and one concern of using nanoparticles.

Answer. (a) Fibre optics (optical fibres) are used; they carry information as pulses of light with little loss, so they transmit data quickly over long distances. (b) Nanotechnology is the making and use of materials at the nanoscale, with structures about 1 to 100 nm in size, where the large surface-area-to-volume ratio gives new properties. (c) Benefit: for example stronger, lighter materials, better sunscreens or targeted drug delivery. Concern: the health and environmental effects of nanoparticles are not yet fully known, so they must be used and regulated carefully.

Exam tip

For modern materials, always give property + use, not just a name, “superconductor: zero resistance, used in MRI magnets”. For nanotechnology, remember the size scale (1–100 nm, 1 nm = 10⁻⁹ m) and the reason for the special behaviour: large surface-area-to-volume ratio. When asked to evaluate, give a benefit and a concern and finish with careful, responsible use. Do not invent statistics about how much stronger or smaller a material is; describe the effect in words unless the numbers are given.

Where this fits

This is content standard 13.6 of the Consumer and Industrial Chemistry chapter, and it closes the chapter by looking at cutting-edge materials. Reinforce it with the chapter revision notes and practise the material-and-use and evaluation questions in the worked examples. In our online 1-to-1 SPM Chemistry lessons, taught in English, from RM50/hr, with a paid one-hour trial, a one-to-one teacher can make sure your surface-area-to-volume explanation and your material-property-use lists are exam-ready, because those are the reliable marks in this part of 4541.

Quick recap

• Modern materials: superconductors (zero resistance, MRI/maglev), fibre optics (light signals, telecoms), liquid crystals (LCD screens), semiconductors (microchips), advanced ceramics and photochromic glass.
• Nanotechnology works at 1–100 nm (1 nm = 10⁻⁹ m).
• Nanoparticles behave differently because of their large surface-area-to-volume ratio, making them more reactive.
• Uses include sunscreens, carbon nanotubes, self-cleaning surfaces, drug delivery and electronics; give a benefit and a concern when evaluating.