Modern & Smart Materials

What are smart materials?

Smart materials have unique properties that change in response to an external stimulus — such as temperature, light, pressure or electrical current. They effectively sense and react to their environment, making them useful in a wide range of products.

Shape Memory Alloys (SMAs)

Shape Memory Alloys return to a pre-set shape when heated after being deformed.

• Nitinol (nickel + titanium) is the most common SMA.
• Used in spectacle frames — frames can be bent or twisted and returned to their original shape when warmed.
• Used in dental braces — Nitinol wire exerts a gentle, consistent force to move teeth into position as it tries to return to its original shape at body temperature.
• Used in medical stents — collapsed for insertion, then expand to their original shape inside the body.

Polymorph

Polymorph is a thermoplastic polymer that becomes soft and mouldable at around 62°C — low enough to soften in hot water.

• Can be shaped by hand when warm and sets rigid when cooled to room temperature.
• Can be reheated and reshaped many times without losing its properties.
• Used for creating custom handles, grips, small prototypes and prosthetic components.
• Useful in D&T for model-making and prototyping because of its ease of use.

Photochromic materials

Photochromic materials change colour when exposed to ultraviolet (UV) light, and return to their original colour when the UV source is removed.

• Used in transition spectacle lenses that automatically darken in sunlight and become clear indoors.
• Used in security printing on banknotes and documents.
• Used in UV-reactive inks for novelty products and safety marking.

Thermochromic materials

Thermochromic materials change colour in response to temperature.

• Used in baby products such as spoons, bottles and bath thermometers to indicate when a temperature is safe.
• Used in mood rings and novelty products.
• Used in food and drink packaging to show whether a product is at the correct serving temperature.
• The colour change is reversible — they return to their original colour when temperature returns to normal.

Micro-encapsulation

Micro-encapsulation is a process where tiny particles or droplets are enclosed in a coating (capsule) to protect them until needed. When the capsule is broken — by pressure, heat or friction — the contents are released.

• Used in scratch-and-sniff products where fragrance capsules are embedded in a surface.
• Used in phase-change materials in textiles — capsules absorb and release heat to regulate body temperature in sportswear and outdoor clothing.
• Used in antibacterial fabrics where capsules release antimicrobial agents gradually over time.
• Used in self-healing materials — capsules containing adhesive release their contents to fill cracks when broken.

Biometrics

Biometrics refers to technology that identifies or authenticates individuals using unique biological characteristics.

• Fingerprint sensors — used in smartphones, laptops and security systems to grant access.
• Facial recognition — used in phone unlocking, passport control and surveillance systems.
• Iris scanning — used in high-security environments.
• Voice recognition — used in smart speakers and banking security.

Biometric technology raises important social and ethical considerations — personal biological data is highly sensitive and its storage and use must be carefully regulated.

Smart fibres and technical textiles

Smart fibres are fibres or fabrics that incorporate smart material properties.

• Conductive fibres woven into fabric allow clothing to carry electrical signals — used in heated jackets, wearable technology and sports performance monitoring.
• Thermochromic dyes in fabric change the colour of clothing with temperature — used in fashion and sportswear.
• Photochromic dyes in fabric change colour in UV light.
• Shape memory fibres can be woven into garments that change shape or tighten in response to temperature or moisture.