Section A - Developments in new materials

Question 1

Define modern materials

Answer 1

Modern material is a material that has recently been developed for specific applications

Question 2

Give examples of some modern materials

Answer 2

Graphene
Metal foam
Titanium
Coated metals
Liquid crystal display
Nanomaterials
Teflon
Corn starch polymers

Question 3

Properties of graphene

Answer 3

Very strong and very light material
Harder than diamond
about 300 times stronger than steel
Transparent
Conducts electricity and heat even better than copper
Stretchable
Extremely flexible (which is unusual for such a strong, tough metal) .
Impermeable to all known substances

Question 4

Uses of graphene

Answer 4

Due to its strength, graphene is being developed for use in protective clothing, vehicles and buildings

Conductive ink is made by mixing tiny graphene flakes with ink (this enable you to print onto paper and use this print to conduct electricity)

Used in solar cells. These cells need conductive materials that allow light to get through them.
Graphene is a suitable material due to its high conductivity and transparency.
Unfortunately it is not very goof at collecting the electrical current produced inside the solar cell (so further developments need to be made) - use of graphene oxide - less conductive but more transparent and a better collector of charge.

Graphene - has been used in paint to act as a barrier between materials and the corroding effects of oxygen and water.
In the future, vehicles could be made corrosion resistant with such paint.

Electronic companies are investigating the use of graphene in touchscreens - since it is able to transfer electrons at much faster speeds than silicon.
This paired with its flexibility, could lead to foldable televisions or computers, and due to its transparency - could lead to virtual windows.

These materials are being developed for use in mobile technology, biomedicine, composites, material coatings and energy storage.

Question 5

What is graphene

Answer 5

A very thin two-dimensional material layer of carbon that was discovered and extracted from carbon in 2004

Question 6

How can be metals be made into a foam

Answer 6

Metals such as aluminium (and sometimes steel or titanium) can be made into a foam by injecting gas into the metal when it is a liquid state.
This creates a foam

Question 7

Properties of metal foam

Answer 7

The foam is very lightweight
Has high compressive strength
Electrically and thermally conductive
Good sound absorption
A very porous material
It can absorb energy well

Question 8

Uses of metal foam

Answer 8

Used as soundproofing Used for crash protection in vehicles as it is light enough to be carried in cars without reducing their speed

It is also being developed in the use of body arm, because it is lightweight and strong

Used in filtration due to its porosity.
Currently being developed for use in prosthetics (artificial body parts) for animals
With the aim of creating prosthetics that are lighter and more comfortable for the user

These materials are commonly used in aircraft, car parts, impact absorption and medical implants.

Question 9

Properties of titanium

Answer 9

High corrosion resistance (even to salt water and chlorine)
High strength-to-density ratio
Strength
Low density

when exposed to the elements it doesn’t go rusty (it can resist the effects of the rain and moisture in the air by reacting with oxygen to produce titanium oxide, which keeps out water and air)

Question 10

Uses of titanium

Answer 10

Its high strength-to-density to ratio, makes it suitable for use in applications such as knee replacements

Its strength and low density makes it a good choice of material for aircrafts

It is also frequently used as titanium oxide.
In this form it is used as a white pigment in plastic and paint and as a sunscreen in cosmetic products

Commonly used for joint and dental implants as the material does not react with the human body making it hypoallergenic.

Also used in jewellery, watches, aircraft and sports cars due to its high strength to weight ratio.

Question 11

What other metal can titanium be allowed with

Answer 11

Titanium can be alloyed with other metals such as aluminium and vanadium

Question 12

Examples of coated metals

Answer 12

Anodised aluminium
Nickel-plated steels
Polymer-coated aluminium

Question 13

What is anodised aluminium

Answer 13

Anodised aluminium is aluminium with a thick oxide layer created by passing a current through an electrolytic solution

Question 14

Why does a current pass through an electrolytic solution for a thick oxide layer to be added with aluminium

Answer 14

This process increases resistance to corrosion and wear, and it makes it easier to paint and glue

Question 15

What is nickel-plated steel

Answer 15

Nickel-plated steel uses the process of electrolysis to add the nickel to a steel object

Question 16

Advantages of using nickel-plated steel

Answer 16

This allows us to use a strong and relatively cheap material such as steel and coat it in a thin later of more expensive nickel which is corrosion resistant and can add an attractive finish to a product

Question 17

What is polymer-coated aluminium

Answer 17

Polymer-coated aluminium can be created by dip coating or powder coating the aluminium.

Question 18

Uses of polymer-coated aluminium

Answer 18

This process is used for products suchas dishwasher racks and tool handles

Question 19

Describe the two ways the polymer can be coated onto the aluminium

Answer 19

Polymer-coated aluminium can be created by dip coating or powder coating the aluminium.

Polythene is often used in powder form for dip coating, whereby the metal is dipped into a liquid polymer.

Powder coating is where the powder is sprayed on to the metal and then cured in an oven

Question 20

Products that have been polymer-coated (aluminium) by powder coating are more what than standard products

Answer 20

These products tend to be more expensive than standard ones as they are particularly hardwearing

Question 21

What is the impact of both processes (dip coating/powder coating) on the product

Answer 21

Both processes create a layer of plastic around the metal which reduces the impact of exposure to air and moisture and provides and attractive and potentially colourful finish to the product

Question 22

Liquid Crystal Displays abbreviated to

Answer 22

LCDs

Question 23

What is a liquid crystal display

Answer 23

A liquid crystal display is a laminated material of two layers of glass with a liquid crystal core.

It is a thin flat panel that lets light go through when a voltage is applied, or blocks the light when the voltage is switched off.

Question 24

Uses of LCDs

Answer 24

LCDs are often used in electronic items such as digital watches and flat-screen televisions, clocks, microwaves, computer monitors, satellite navigation systems

Many LCDs work well by themselves when there is other light around but others need a back light(such as for smartphones, computer monitors and televisions)

Question 25

Properties of LCSs

Answer 25

These displays have low power consumption, create sharp images, and are compact and flat. Liquid crystal displays are found in a monochrome or colour display format. Numbers or letters are displayed when a voltage is applied to create a symbol or image.

Question 26

What are nanomaterials

Answer 26

Nanomaterials have tiny parts less than 100 nanometres in size

Question 27

How many metres is a nanometre

Answer 27

A nanometre is one billionth of a metre 1 x 10^-9 of a metre

Question 28

Uses of nanomaterials

Answer 28

Nanomaterials are used as surface coating or thin films, such as on computer chips Used in sports equipment such as tennis rackets and golf shoes (where nanoparticles are added to materials to make them stronger while not substantially increasing the weight) Nanoparticles are also used in clothing such as socks due to their antibacterial properties, to reduce the absorption of sweat

Question 29

Properties

Answer 29

Antibacterial properties Oil repelant Water repelant

Question 30

What is a smart material

Answer 30

A smart material is a material that changes its properties in response to changes in its environment

Question 31

Give examples of some external stimuli/influences that could stimulate change in a material

Answer 31

Stress Temperature Moisture pH

Question 32

What types of changes occur when a smart material changes its properties

Answer 32

These changes are often reversible when the environment changes again

Question 33

Examples of smart materials

Answer 33

Shape memory alloys Thermochromic pigments Photochromic pigments

Question 34

What are thermochromic pigments

Answer 34

Thermochromic materials are materials that change colour as specific temperatures

Question 35

What are thermochromic pigments/materials available as

Answer 35

They are available as plastic, ink, and dyes for textiles and paint

Question 36

Uses of thermochromic pigments

Answer 36

Test strips on batteries (when the strip is pressed at each end and if the battery is in good condition, current flows through a printed resistor under thermochromic film, this heats the resistor producing a colour change) Plastic strips used as thermometers that are applied to children's foreheads Colour indicators on drinks cans to show whether the contents are cold enough Mugs that change colour when hot water is added Baby spoons that change colour when the food is too hot - these are a safety feature to ensure the child's food is a safe temperature T-shirts that change colour

Question 37

What is a shape memory alloy

Answer 37

If materials made from shape memory alloys (SMAs) are bent or deformed they will return to their original shape when heated.

Question 38

When is it a useful property that a product can return to its original shape, when heated (after its been bent/deformed)/is a Shape memory alloy

Answer 38

It is a useful property when: a response to a change in temperature is needed (for example, in fire alarm systems or controllers for hot water valves in showers) Movement is needed from an electrical current (in electric door locks, rotary movement and artificial muscles in robot arms) - the temperature change can be achieved by passing an electrical current through the thin product or wire A damaged product needs to be repaired (for example, if someone bends a glasses frame, it can be returned to its original shape by being heated)

Question 39

Shape memory alloy abbreviation

Answer 39

SMAs

Question 40

What are photochromic pigments

Answer 40

Photochromic materials/pigments change colour if the level of light changes

Question 41

When does the pigment colour usually change in photochromic pigmnts

Answer 41

The pigment colour usually changes when exposed to UV light where they lighten or darken once the light is taken away.

Question 42

Examples of products that use photochromic pigments

Answer 42

Lenses in sunglasses that become lighter or darker depending on the light conditions Security markers that can only be seen in ultraviolet light Photochromic windows that change their transparency according to how much light there is; these reduce glare and help prevent cooling systems in buildings from overloading Bracelets that change colour to tell you if you are getting too much sun - these can be an indicator to tell you to reapply sun cream

Question 43

What is a composite material

Answer 43

Composite materials are produced by combining two or more different materials and the properties of the materials they are made from to create an enhanced material

Question 44

Examples of composite materials

Answer 44

Glass reinforced plastic (GRP) Carbon-fibre reinforced plastic (CRP)

Question 45

What is the composition Glass reinforced plastic

Answer 45

Glass reinforced plastic combines strands of glass fibres which are strong but brittle, with a flexible polymer resin This makes a composite material that is tough but not brittle

Question 46

What is Glass reinforced Plastic used for

Answer 46

GRP is used to make hulls for yachts, and car bodies Instrument cases

Question 47

Properties of GRP

Answer 47

Lightweight Waterproof Chemically resistant Corrosion-resistant Heat resistant Good strength-to-weight ratio Tough Not brittle (can be expensive)

Question 48

Properties of Carbon-fibre reinforced plastic (CRP)

Answer 48

High strength-to-weight ratio (better than GRP) It gives a high-quality finish Waterproof Expensive Chemically resistant Corrosion-resistant Heat resistant

Question 49

What is Carbon-fibre reinforced plastic made from

Answer 49

Carbon fibre and resin

Question 50

Uses of carbon fibre reinforced plastic

Answer 50

Formula 1 car bodies Crash helmets Sports equipment Boats Prosthetics Sports cars/super car Musical instuments High strength-to-weight ration makes it popular in products which take very harsh loading and need to be lightweight e.g. those used in the aerospace industry and motor racing

Question 51

What are technical textiles

Answer 51

Technical textiles are textile materials and products that are manufactured for their technical and performance properties (rather than their aesthetic characteristics)

Question 52

Examples of technical textiles

Answer 52

Conductive fabrics Fire resistant fabrics Kevlar Microfibres (incorporating Micro encapsulation)

Question 53

What are conductive fabrics

Answer 53

Conductive fabrics are fabrics that have either conductive fibres woven into them or conductive powders impregnated into them

Question 54

Properties/characteristics of conductive fabrics

Answer 54

These fabrics allow a small electrical current to pass safely through them

Question 55

Uses and applications of conductive fabrics

Answer 55

Conductive thread is useful for use in circuits that power LEDs Conductive materials have been built in to competitors jackets for fencing contests to help with scoring systems These materials are useful in touch-screen gloves, which allow a small amount of charge to flow through the glove to connect to the screen Can be used to dissipate static charge Children's electronic toys Anti-static clothing Used in connection of wearable technology/blue tooth connectivity and speakers in clothing

Question 56

What are fire resistant fabrics

Answer 56

Fire resistant fabrics are a textile material that is resistant to fire

Question 57

Properties and characteristics of fire resistant fabrics

Answer 57

Fabrics that are more resistant to fire than others, through chemical treatment or manufactured fireproof fibres

Question 58

Uses and applications of fire resistant fibres

Answer 58

Used in fire blankets, firefighters safety clothing, gloves, aprons, racing car driving protection, children's nightwear and cotton/viscose furnishings

Question 59

Properties and characteristics of kevlar

Answer 59

When combined with layers of resin, the result is a very light material that has high tensile strength (it has a stretching or pulling strength over eight times greater than that of steel wire) high tensile strength- to-weight ratio Does not melt - can withstand extreme temperatures (temperatures up to 450 degrees celcius and temperatures up to -196 degrees celcius) Cam resist attacks from many different chemicals Hard wearing Cut and tear- resistant Non-flammable Strong

Question 60

Uses and applications of kevlar

Answer 60

Used in the production of personal armour such as bullet proof vests, helmets, face masks, motorcycle safety clothing Used in sports equipment, such as inner linings for bicycle tyres and table tennis bats (due to its high strength-to-weight ratio)

Question 61

What is a microfibre

Answer 61

A microfibre is a very thin synthetic fibre

Question 62

Properties and characteristics of microfibres

Answer 62

Breathable Durable Crease resistant Easy to care for Can be coiled to provide a very warm, soft or absorbent material Absorbent Fast drying

Question 63

Uses and applications of microfibres

Answer 63

Used for outdoor clothing and sportswear because they are breathable, durable, crease resistant and easy to care for Very fine polyamide and polyester microfibres are used for sportswear and lingerie garments Tencel microfibre is used for shirts Microfibres can be coiled to provide a very warm, soft or absorbent material that can be used in winter clothes or products such as cleaning cloths Can be statically charged to pick up dust, filter particles

Question 64

What type of fibre incorporates microencapsulation

Answer 64

Some microfibres incorporate microencapsulation

Question 65

What is microencapsulation

Answer 65

Microencapsulation is a process in which very tiny fibres hold chemicals in tiny capsules, which break open releasing the chemicals

Question 66

Properties and characteristics of micro-encapsulatoin

Answer 66

The capsules gradually break releasing chemicals like perfumes, insecticides or antisepctics

Question 67

Advantages of micro-encapsulation

Answer 67

Due to the fact the capsules gradually break releasing chemicals like perfumes, insecticides or antiseptics. It means that the wearer can benefit from these functions throughout their time of use This can bring benefits such as smelling good to cover body odours in sports clothing.

Question 68

Uses and application of micro-encapsulation

Answer 68

This technology has been used in the manufacture of outdoor clothing that repels mosquitos and other biting and stinging insects Used to add scent to fabrics Used in clothing which holds a perfume released over time Used in soft furnishings e.g. curtains for children's bedrooms that smell of sweets / bedsheets that smell of lavender to encourage a good night's sleep These materials are commonly used in medical textiles, fabrics, cloths, towels, high tech clothing which can be anti-bacterial and insect repelling.