Modern Materials and Smart Materials
Modern Materials and Smart Materials
AQA GCSE D&T requires you to understand materials that have been developed relatively recently or have unusual properties that make them useful in innovative products.
Modern Materials
Modern materials are those developed through the invention of new or improved processes. They offer enhanced properties compared to traditional alternatives.
| Material | Description | Properties | Example Uses |
|---|---|---|---|
| Graphene | Single layer of carbon atoms in a hexagonal lattice | Strongest known material, excellent conductor, flexible, transparent | Touchscreens, batteries, water filtration |
| Metal foams | Metals with gas-filled pores (typically aluminium) | Lightweight, good energy absorption, high stiffness-to-weight ratio | Car crash structures, aerospace, building panels |
| Titanium | Low-density metallic element | Very strong, corrosion resistant, biocompatible, lightweight | Medical implants, aircraft, sports equipment |
| Coated metals | Metals with a surface layer of another material | Enhanced corrosion resistance, improved aesthetics | Tin-plated steel (food cans), galvanised steel (outdoor structures) |
| Liquid crystal displays (LCD) | Layers of liquid crystals between polarising filters | Low power, thin profile, adjustable brightness | Screens, watches, calculators |
| Nanomaterials | Materials engineered at the atomic/molecular scale (1-100 nm) | Enhanced strength, conductivity, or reactivity | Self-cleaning glass (nano-TiO2), antibacterial coatings |
| Corn starch polymers (PLA) | Biodegradable thermoplastic from plant starch | Compostable, renewable source, food-safe | Disposable cutlery, food packaging, 3D printing filament |
Smart Materials
Smart materials change their properties in response to an external stimulus (e.g. temperature, light, pressure, voltage). The change is reversible — this distinguishes them from modern materials.
| Material | Stimulus | Response | Example Uses |
|---|---|---|---|
| Thermochromic pigments | Temperature change | Change colour | Baby spoons (warn if food is too hot), mood rings, mugs |
| Photochromic pigments | UV light intensity | Change colour (darken in sunlight) | Transition lenses in glasses, security printing |
| Shape memory alloys (SMA) | Temperature change | Return to a pre-set shape when heated | Dental braces (nitinol wire), fire sprinkler valves, stents |
| Piezoelectric materials | Mechanical stress / electrical voltage | Generate voltage when stressed, or deform when voltage applied | Lighters, sensors, energy-harvesting floor tiles |
| Quantum tunnelling composite (QTC) | Pressure | Changes from insulator to conductor when compressed | Touch-sensitive switches, pressure sensors in robotics |
| Electroluminescent materials | Electrical current | Emit light | Safety clothing, dashboard displays, decorative lighting |
Comparing Smart and Modern Materials
| Feature | Smart Materials | Modern Materials |
|---|---|---|
| Response to stimuli | Yes — reversible change | No — properties are fixed |
| Development | Often recent inventions | Developed through new processes or combinations |
| Key characteristic | React and return to original state | Improved performance over traditional materials |
| AQA focus | Know the stimulus and response | Know properties and applications |
Composite Materials
A composite is a material made from two or more constituent materials with different properties, combined to produce a material with superior characteristics. The components remain separate and distinct within the finished structure.
| Composite | Components | Properties | Uses |
|---|---|---|---|
| Glass Reinforced Plastic (GRP/fibreglass) | Glass fibres + polyester resin | Lightweight, strong, mouldable, corrosion resistant | Boat hulls, car body panels, storage tanks |
| Carbon Fibre Reinforced Polymer (CFRP) | Carbon fibres + epoxy resin | Extremely strong, very lightweight, stiff | F1 cars, bicycle frames, aircraft wings |
| Concrete | Cement + aggregate + sand + water | High compressive strength, versatile, cheap | Buildings, bridges, infrastructure |
| Plywood | Layers of wood veneer glued at 90° | Resists warping, strong in all directions, large sheets | Furniture, construction, flooring |
Technical Textiles
Technical textiles are engineered for performance rather than aesthetics:
- Gore-Tex — waterproof but breathable membrane (microporous PTFE)
- Kevlar — extremely strong aramid fibre used in body armour and cut-resistant gloves
- Nomex — heat and flame-resistant textile for firefighter uniforms
- Conductive fabrics — threads woven with metallic fibres for wearable electronics
Exam Tips
- The most common question type asks you to name a smart material, state its stimulus and response, and give a use — practise this as a quick-fire drill
- Always specify whether a material is smart (reversible response to stimulus) or modern (improved properties, no stimulus response)
- When discussing composites, explain why combining the materials gives better properties than either alone
- Be prepared to suggest suitable materials for a given design scenario — link properties to the product's function
- Do not confuse thermochromic (heat) with photochromic (light) — examiners test this regularly
Key Definitions
- Smart material: A material that reacts to changes in its environment in a useful, predictable and reversible way
- Composite: A material made from two or more different materials that, when combined, produce enhanced properties
- Stimulus: An external change (e.g. heat, light, pressure) that causes a smart material to respond
- Technical textile: A textile designed and engineered for functional performance rather than appearance