1.3 - Development in New Materials

Question 1

What are some examples of modern materials?

Answer 1

• Graphene
• Metal foam
• Liquid crystal display
• Coated metals
• Titanium
• Nanomaterials

Question 2

What is Graphene? (Modern material)

Answer 2

• Graphene is a single layer of carbon atoms, tightly bound in a hexagonal lattice.
• It is the thinnest known material to date, extremely strong, light and conductive to heat and electricity.
• Used in sports equipment, cooling technology in mobile phones, batteries, solar applications, aerospace and more.

Question 3

What is metal foam? (Modern material)

Answer 3

• Metal foams are a cellular structure made up from metal containing gas filled pores.
• With good stiffness to weight ratio, they are strong, resist deformation and can be made into complex geometrical forms.
• Foams have good heat resistance and sound absorption.
• Used for weight saving and impact absorbing structures in vehicles.

Question 4

What is liquid crystal display (LCD)? (Modern material)

Answer 4

• Low-power LCD displays such as televisions, contain a matrix of pixels that display an image on the screen.
• A backlight provides light to the individual pixels.
• By varying the levels of red, green and blue light, millions of colour combinations are created and displayed.

Question 5

What are coated metals? (Modern material)

Answer 5

• Metal coatings help protect metal, make it more durable and reduce wear and tear.
• An unprotected ferrous metal is liable to rust and corrosion due to exposure to the environment.
• Examples include galvanised steel, plastic coatings such as Teflon, anodising, thermoplastic dip coating and painting.

Question 6

What is Titanium? (Modern material)

Answer 6

• Found in the earth’s crust, Titanium is used in the form of an alloy.
• It has high strength, is lightweight and resists corrosion.
• These properties make it suitable for use in missiles, space and aircraft. It does not react with human tissue so is used in medicine for artificial joints.

Question 7

What are nanomaterials? (Modern material)

Answer 7

• Nanomaterials are materials or substances made at a very small scale.
• These natural or manufactured materials contain particles less than 100 nanometres in size.
• Nanotechnology adds properties to products, such as lightness, tensile strength and rigidity.
• These are being used in electronics and the world of medicine.
• Nanotechnology is able to incorporate useful properties into textiles which can make them resistant to bacteria, super hydrophobic (water repellent), repel dirt and neutralise bad odours.

Question 8

What are smart materials?

Answer 8

• Smart materials are responsive materials that are designed to react to external stimuli.
• They can alter the functional or aesthetic properties in response to a changing environment.

Question 9

What is a modern material?

Answer 9

A modern material is a material that has been engineered to have improved properties.

Question 10

What are some examples of external stimuli?

Answer 10

• Stress
• Temperature
• Moisture, pH levels
• Electric or magnetic fields
• UV Light

Question 11

What are some examples of smart materials?

Answer 11

• Polymorph
• Shape memory alloy (SMA)
• Quantum tunnelling composite (QTC)
• Thermochromic materials
• Photochromic materials
• Phosphorescent materials
• Piezoelectric materials
• Ferrofluids
• Self-healing materials

Question 12

What is Polymorph? (Smart materials)

Answer 12

• Polymorph is a polymer that can be shaped and reshaped many times.
• When warmed to 62°C, the polymorph becomes flexible and easy to mould into the desired shape.
• It sets as it cools and becomes stiff and strong.
• It can be used for making bespoke shapes such as ergonomic handles, is useful for making prototype mechanical parts and for making mouldings.

Question 13

What is shape memory alloy (SMA)? (Smart material)

Answer 13

• SMAs are a group of materias that revert back to their original shape after being deformed by heat or another external stimulus.
• Nitinol is an SMA with thermal shape memory properties.
• It is used in dentistry for braces, for activating a variable resistor or switch when there is a fluctuation in temperature, frames for spectacles and self-bending spoons in magic shows.
• It is also super-elastic, Nitinol mesh is used for expandable stents in vascular surgery.

Question 14

What is Quantum Tunnelling Composite (QTC)

Answer 14

• QTC is a flexible polymer with tiny metal particles embedded into it.
• It is an insulator when resting and a conductor when pressure is applied.
• It is used in microswitches, outdoor items that may be affected by water and touch sensitive pads.

Question 15

What are thermochromic materials? (Smart material)

Answer 15

• Thermochromic pigments are temperature sensitive.
• They change colour at certain ranges of temperature, be it cold activations, rub and reveal or hot applications.
• They can be incorporated into inks and printed onto plastic in the form of temperature indicators.

Question 16

What are photochromic materials? (Smart material)

Answer 16

• Photochromic pigments change colour when exposed to different UV levels.
• In the example of glasses, the lens may darken when exposed to bright sunlight and reverse to colourless once removed from the UV source.
• They are also used in textile printing inks and novelty toys.
• Over time the pigments degrade from over exposure to UV light.

Question 17

What are phosphorescent materials? (Smart material)

Answer 17

• Phosphorescence is a process whereby energy from the sun is absorbed by a material and it is released slowly over a long time, in the form of light.
• The light emitted is at a low intensity and this can last for many hours.
• Used in glow-in-the-dark toys, stickers, paint, wrist watch and clock dials.

Question 18

What are piezoelectric materials? (Smart material)

Answer 18

• Generates a small electric charge when sensors are compressed.
• Can also generate movement when an electric charge is applied (actuator).
• Used to generate energy, sensors, burglar alarms, keyless car entry, seat belt sensors, actuators, digital cameras.

Question 19

What are self-healing materials? (Smart material)

Answer 19

• Self-healing materials have the ability to repair themselves, which can extend the lifespan of the products that use them.
• These include polymers that can heal knife cuts in themselves, metals that resist corrosion and concrete that can heal when cracked.

Question 20

What are ferrofulids? (Smart materials)

Answer 20

• Ferrofluids can be formed by a magnetic field and are being used in hydraulic suspension pistons, with the strength of the magnetic field allowing the suspension to be hard or soft depending on what is necessary.
• They also have friction reducing properties allowing magnetic objects to glide across the surface.

Question 21

Exam Style Question:
A motorcycle helmet manufacturer is considering the use of photochromic pigments on its visors.

Explain one disadvantage of using photochromic particles with helmet visors.
[2]

Answer 21

• They take up to two minutes to darken or lighter.
• This can cause issues when entering dark tunnels or going straight out into bright sunlight.
• They can lose their ability to turn back to clear over time.
• This means they become less effective in different light levels.

Question 22

What is a composite material?

Answer 22

• A composite material is composed of at least two materials.
• When combined, the properties are superior to those of the individual components.

Question 23

What are the three main categories of composite materials?

Answer 23

• Fibre-based composites
• Particle-based composites
• Sheet-based composites

Question 24

What are fibre-based composites? List some examples.

Answer 24

By mixing resin or concrete with fibres we get the ability to mould complex shapes, but reinforcing them with the fibres makes them very strong.

• Glass-reinforced plastic (GRP)
• Carbon-reinforced plastic (CRP)
• Glass-reinforced concrete (GRC)

Question 25

What are particle-based composites? List some examples.

Answer 25

By mixing smaller particles of sand with larger particles of cement and aggregate, such as stones, we get a very strong and dense material suitable for building large structures.

• Concrete
• Cermet

Question 26

What are sheet-based composites? List some examples.

Answer 26

By mixing wood fibres or thin slices of wood veneers with resin it is possible to form large and stable sheets for furniture panels and interior construction.

• Medium-density fibreboard (MDF)
• Plywood
• Chipboard

Question 27

What is glass reinforced plastic (GRP)? (Composite material)

Answer 27

• GRP is a polyester material reinforced with the addition of glass fibre.
• It is produced by combining thermosetting polyester resin and glass fibre matting making a strong and lightweight composite.
• GRP is used in the manufacture of circuit boards, in the marine industry for boat hulls and in the custom kit car market.

Question 28

What is Carbon fibre reinforced plastic (CRP)? (Composite material)

Answer 28

• CRP is a thermoplastic reinforced with carbon fibres.
• It has a high strength to weight ratio and is very rigid.
• It is used in aerospace engineering for fuselage components, Formula One vehicle chassis and many items of sports equipment including running blades used by para-athletes.

Question 29

What are technical textiles?

Answer 29

• Technical textiles are manufactured for their function and performance.
• They can be made from a combination of natural and synthetic fibres or filaments, and be coated, laminated or implanted to improve the properties and performance of the finished item.
• Technical textiles are used in automotive and aerospace applications, for geotextiles and for agrotextiles.

Question 30

What is Gore-Tex? (Technical textile)

Answer 30

• Gore-Tex is a fabric with breathable yet waterproof properties.
• It allows vapour produced by the wearer to escape, yet repels water making it an effective waterproof fabric commonly used for outdoor clothing.

Question 31

What is Kelvar? (Technical textile)

Answer 31

• Kevlar is a tightly woven fabric that has great impact resistance.
• It is used in racing tyres, racing sails, gardening gloves and bulletproof vests.

Question 32

What are microfibres and micro-encapsulation? (Technical textile)

Answer 32

• Microfibres are synthetic fibres, less than one denier thick which can be micro-encapsulated.
• Micro-encapsulation is a process of adding a coating to tiny particles or droplets.
• The particles improve the properties of microfibre as they can hold anti-microbial agents, insecticides, moisturisers and medicines to be released under control.

Question 33

What are fire resistant fabrics? (Technical textile)

Answer 33

• Fire resistant fabrics are designed to withstand heat and resist burning.
• They are primarily used for protective clothing for fire fighters.

Question 34

What is Nomex? (Technical fibre)

Answer 34

• Nomex® is an example of a fire resistant fabric when Nomex is exposed to heat, its fibres thicken and absorb heat energy.
• As it is lightweight and durable, it is also used in racing driver and pit crew apparel.

Question 35

What are conductive fabrics? (Technical fibres)

Answer 35

• Conductive fabrics are made from, coated or blended with, conductive metals.
• They can be used for thermal heating or allowing an electrical signal to pass through them with very little resistance.
• These e-textiles can also have batteries, small lights and electronics embedded into them, and are often fitted into sportswear to monitor vital statistics.