Section A - Developments in new materials Flashcards
Define modern materials
Modern material is a material that has recently been developed for specific applications
Give examples of some modern materials
Graphene
Metal foam
Titanium
Coated metals
Liquid crystal display
Nanomaterials
Teflon
Corn starch polymers
Properties of graphene
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
Uses of graphene
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.
What is graphene
A very thin two-dimensional material layer of carbon that was discovered and extracted from carbon in 2004
How can be metals be made into a foam
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
Properties of metal foam
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
Uses of metal foam
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.
Properties of titanium
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)
Uses of titanium
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.
What other metal can titanium be allowed with
Titanium can be alloyed with other metals such as aluminium and vanadium
Examples of coated metals
Anodised aluminium
Nickel-plated steels
Polymer-coated aluminium
What is anodised aluminium
Anodised aluminium is aluminium with a thick oxide layer created by passing a current through an electrolytic solution
Why does a current pass through an electrolytic solution for a thick oxide layer to be added with aluminium
This process increases resistance to corrosion and wear, and it makes it easier to paint and glue
What is nickel-plated steel
Nickel-plated steel uses the process of electrolysis to add the nickel to a steel object
Advantages of using nickel-plated steel
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
What is polymer-coated aluminium
Polymer-coated aluminium can be created by dip coating or powder coating the aluminium.
Uses of polymer-coated aluminium
This process is used for products suchas dishwasher racks and tool handles
Describe the two ways the polymer can be coated onto the aluminium
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
Products that have been polymer-coated (aluminium) by powder coating are more what than standard products
These products tend to be more expensive than standard ones as they are particularly hardwearing
What is the impact of both processes (dip coating/powder coating) on the product
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
Liquid Crystal Displays abbreviated to
LCDs
What is a liquid crystal display
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.
Uses of LCDs
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)
Properties of LCSs
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.
What are nanomaterials
Nanomaterials have tiny parts less than 100 nanometres in size
How many metres is a nanometre
A nanometre is one billionth of a metre
1 x 10^-9 of a metre
Uses of nanomaterials
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
Properties
Antibacterial properties
Oil repelant
Water repelant
What is a smart material
A smart material is a material that changes its properties in response to changes in its environment
Give examples of some external stimuli/influences that could stimulate change in a material
Stress
Temperature
Moisture
pH
What types of changes occur when a smart material changes its properties
These changes are often reversible when the environment changes again
Examples of smart materials
Shape memory alloys
Thermochromic pigments
Photochromic pigments
What are thermochromic pigments
Thermochromic materials are materials that change colour as specific temperatures
What are thermochromic pigments/materials available as
They are available as plastic, ink, and dyes for textiles and paint
Uses of thermochromic pigments
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
What is a shape memory alloy
If materials made from shape memory alloys (SMAs) are bent or deformed they will return to their original shape when heated.
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
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)
Shape memory alloy abbreviation
SMAs
What are photochromic pigments
Photochromic materials/pigments change colour if the level of light changes
When does the pigment colour usually change in photochromic pigmnts
The pigment colour usually changes when exposed to UV light where they lighten or darken once the light is taken away.
Examples of products that use photochromic pigments
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
What is a composite material
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
Examples of composite materials
Glass reinforced plastic (GRP)
Carbon-fibre reinforced plastic (CRP)
What is the composition Glass reinforced plastic
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
What is Glass reinforced Plastic used for
GRP is used to make hulls for yachts, and
car bodies
Instrument cases
Properties of GRP
Lightweight
Waterproof
Chemically resistant
Corrosion-resistant
Heat resistant
Good strength-to-weight ratio
Tough
Not brittle
(can be expensive)
Properties of Carbon-fibre reinforced plastic (CRP)
High strength-to-weight ratio (better than GRP)
It gives a high-quality finish
Waterproof
Expensive
Chemically resistant
Corrosion-resistant
Heat resistant
What is Carbon-fibre reinforced plastic made from
Carbon fibre and resin
Uses of carbon fibre reinforced plastic
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
What are technical textiles
Technical textiles are textile materials and products that are manufactured for their technical and performance properties (rather than their aesthetic characteristics)
Examples of technical textiles
Conductive fabrics
Fire resistant fabrics
Kevlar
Microfibres (incorporating Micro encapsulation)
What are conductive fabrics
Conductive fabrics are fabrics that have either conductive fibres woven into them or conductive powders impregnated into them
Properties/characteristics of conductive fabrics
These fabrics allow a small electrical current to pass safely through them
Uses and applications of conductive fabrics
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
What are fire resistant fabrics
Fire resistant fabrics are a textile material that is resistant to fire
Properties and characteristics of fire resistant fabrics
Fabrics that are more resistant to fire than others, through chemical treatment or manufactured fireproof fibres
Uses and applications of fire resistant fibres
Used in fire blankets, firefighters safety clothing, gloves, aprons, racing car driving protection, children’s nightwear and cotton/viscose furnishings
Properties and characteristics of kevlar
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
Uses and applications of kevlar
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)
What is a microfibre
A microfibre is a very thin synthetic fibre
Properties and characteristics of microfibres
Breathable
Durable
Crease resistant
Easy to care for
Can be coiled to provide a very warm, soft or absorbent material
Absorbent
Fast drying
Uses and applications of microfibres
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
What type of fibre incorporates microencapsulation
Some microfibres incorporate microencapsulation
What is microencapsulation
Microencapsulation is a process in which very tiny fibres hold chemicals in tiny capsules, which break open releasing the chemicals
Properties and characteristics of micro-encapsulatoin
The capsules gradually break releasing chemicals like perfumes, insecticides or antisepctics
Advantages of micro-encapsulation
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.
Uses and application of micro-encapsulation
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.
