Examples of Smart Materials and their Uses

Cambridge Design & Technology students have to be familiar with smart materials and their common applications and uses. This article includes illustrated examples of smart materials and provides sample examination questions to help you revise this topic.

Smart materials in Design & Technology

What are smart materials? (A definition)

Smart materials are those that respond to a change in the environment or to a new input – for example, materials that change in response to electricity, temperature, pressure, or light. Smart materials change in a reversible way, so when the external stimuli is removed, they return to their original form.

Note: Some students get confused and think this topic might be related to ‘smart’ phones or advancements in technology. However, ‘smart’ in this context relates to the material’s ability to change its form in response to an external stimuli.

Examples of smart materials

Phosphorescent pigments

Properties

Uses

Absorb light energy (usually UV or visible light) and then slowly release it
Glow-in-the-dark” effect
Exit signs
Emergency pathway markers
Toys

Photochromic pigments

Properties

Uses

Change colour when exposed to light of specific wavelengths (usually UV)
Return to their original colour when the light source is removed
Sunglasses that are clear inside by darken when you go outside
Windows that darken to prevent overheating

Thermochromic pigments

Properties

Uses

Change colour in response to heat
Can be mixed with paints or polymers to give them the same properties
Colour-changing mugs that change when filled with a hot drink
Kettle that changes colour when boils
Bath items for children

Nickel-titanium

Properties

Uses

Contracts when heated (most metals expand)
Superelastic – can undergo large deformations and return to original shape
Safe for human body
Corrosion resistant
10 – 50x more expensive than stainless steel
Braces that get ‘tighter’ in mouth, pulling on the teeth
Medical devices
Surgical instruments
Eyewear – unbreakable glasses frames
Temperature activated switches and connectors

Copper-aluminium-nickel

Properties

Uses

Has a similar shape memory effect to nickel-titanium but less precise
More affordable – much cheaper than nickel-titanium (budget option)
Good electrical conductivity
Temperature controlled switches and valves

Shape memory means it ‘remembers’ its prior shape and returns to that shape when heated to a specific temperature.

Hydrogels

Properties

Uses

Polymer mixture suspended in water – can absorb 10-1,000x their weight in water while maintaining its structure
Absorption capacity alters in response to temperature, light, or chemical changes
Wound dressings
Diapers
Female hygiene products
Edible films

Shape memory polymers

Properties

Uses

Soft rubbery consistency
Can increase in size a lot more than shape memory alloys
PLA is one example
Many uses
Can be used to make smart fabrics

Shape Memory Polymers: Plastic with a Brain, and Some Muscle

Modern and smart materials are constantly being engineered, so it’s good to try to keep up to date with the latest developments. They can often be incorporated into new consumer products without people noticing.

Smart materials are a type of modern materials (although not all modern materials are smart).