1.1.2 Modern & Smart Materials
D&T 2026 — 1.1 Core Knowledge & Understanding
Modern and smart materials
Smart material — a material whose properties change in a controlled, usually reversible way in response to an external stimulus such as heat, light, pressure, moisture or electricity.
Modern material — a material developed through new or improved processes, designed to have properties that traditional materials cannot offer.
The difference matters. A modern material such as carbon fibre is impressive because of the properties it has; a smart material is useful because of the way its properties change.
Smart materials are developed as fibres, fabrics and plastics as well as metals, which is why they appear in every pathway — the same thermochromic pigment can be printed onto a mug, moulded into a spoon or dyed into a T-shirt.
How smart materials respond to stimuli
| Material | Stimulus | Response |
|---|---|---|
| Photochromic | Ultraviolet light | Changes colour, reversing in the dark |
| Thermochromic | Temperature | Changes colour, reversing on cooling |
| Shape memory alloy (SMA) | Heat | Returns to a pre-set shape |
| Polymorph | Heat (around 62°C) | Softens and becomes mouldable, then sets rigid |
| Micro-encapsulation | Pressure, friction or heat | Capsules burst and release their contents |
Photochromic materials
Photochromic materials change colour when exposed to ultraviolet light and return to their original colour when the UV source is removed.
- Transition spectacle lenses darken in sunlight and clear indoors.
- UV-reactive inks on banknotes, passports and event wristbands for security marking.
- UV indicator beads and wristbands that warn when sunlight is strong enough to burn skin.
- The change is reversible and can be repeated many times, though the pigment fades with long exposure.
Thermochromic materials
Thermochromic materials change colour in response to temperature.
- Baby spoons, bottles and bath thermometers that show when something is too hot to be safe.
- Kettles and mugs that display when the contents are at drinking temperature.
- Battery test strips, where resistance heats the strip and the colour shows the charge.
- Food packaging indicating whether a chilled product has been kept cold enough.
Shape memory alloys
Shape memory alloy — an SMA: a metal alloy that returns to a pre-set shape when heated, after being deformed while cool.
- Nitinol — an alloy of nickel and titanium — is the most widely used SMA.
- Spectacle frames made from nitinol spring back after being bent or sat on.
- Dental braces use nitinol wire, which applies a gentle constant force at body temperature as it tries to return to its original shape.
- Medical stents are inserted collapsed and expand to their proper shape inside the body.
- Thermal safety devices use an SMA element to shut a valve or release a catch when a set temperature is reached.
Polymorph
Polymorph is a thermoplastic supplied as small granules that become soft and mouldable at around 62°C — low enough to soften in hot water rather than an oven.
- Shaped by hand while warm, setting rigid and tough as it cools to room temperature.
- Can be reheated and reshaped repeatedly without losing its properties, so mistakes are recoverable.
- Used for custom handles and grips, ergonomic mock-ups, splints and prosthetic fittings.
- Especially useful in school workshops for quick modelling of shapes that would be slow to machine.
Micro-encapsulation
Micro-encapsulation encloses tiny droplets or particles inside a protective coating. The contents stay sealed until the capsule is broken by pressure, friction or heat.
- Scratch-and-sniff print, where rubbing bursts fragrance capsules.
- Fragranced and moisturising textiles, where capsules release their contents gradually as the garment is worn.
- Antibacterial fabrics used in sportswear and medical textiles.
- Phase changing materials in clothing and bedding, where capsules absorb heat as they melt and release it as they solidify, evening out temperature.
- Self-healing materials, where capsules of adhesive burst into a crack and seal it.
Biometrics
Biometrics — technology that identifies a person from a unique biological characteristic such as a fingerprint, face, iris or voice.
- Fingerprint sensors in phones, laptops, door locks and payment terminals.
- Facial recognition for unlocking devices and at automated passport control.
- Iris scanning in high-security buildings.
- Voice recognition in smart speakers and telephone banking.
Biometric data is convenient because it cannot be forgotten like a password, but it also cannot be changed if it is stolen. Designers using biometrics have to consider how the data is stored, who can access it, and whether the system works equally well for all users.
Smart fibres and fabrics
Smart properties can be built into textiles at fibre, yarn or finish stage.
- Conductive fibres woven into fabric carry electrical signals, allowing heated jackets, wearable health monitors and touch-sensitive garments.
- Thermochromic and photochromic dyes change the colour of a garment with temperature or sunlight.
- Shape memory fibres allow a fabric to tighten, loosen or change texture in response to heat or moisture.
- Micro-encapsulated finishes add fragrance, insect repellent or temperature regulation to an ordinary fabric.