Modern, Smart & Composite Materials
Modern, Smart & Composite Materials
Designers increasingly reach for materials that go beyond traditional metals, woods, polymers and textiles. Modern and smart materials react to their environment, composite materials combine two or more materials to get the best of each, and technical textiles are engineered purely for performance. This lesson covers the material types set out in the specification’s coverage of modern, smart, composite and technical textile materials.
Modern and Smart Materials
A shape-memory alloy (SMA) can be bent out of shape, but when it is heated past a set temperature it snaps back to its original form. This reversible behaviour makes SMAs useful anywhere a product needs to change shape automatically, such as self-adjusting fittings or components that respond to a temperature change without any motor or switch.
A nanomaterial is engineered at a tiny, nanometre scale. Working at this scale can give a material properties it would not otherwise have — for example, a coating built from nanomaterials might repel water, resist scratching or stop bacteria growing on a surface, all without changing how the product looks.
Reactive glass changes a property such as tint or opacity when conditions around it change, for example darkening in bright light. A piezoelectric material generates a tiny electrical charge when it is squeezed or placed under pressure — useful for sensors that detect force or vibration, or for turning a mechanical knock into a usable electrical signal.
A temperature-responsive polymer changes its shape or texture as the temperature around it rises or falls, which is useful for products that need to respond automatically to heat without any electronics. Conductive ink contains particles that conduct electricity, so it can be printed straight onto paper, card or fabric to create a flexible circuit rather than using traditional wires.
Shape-memory alloys, nanomaterials, reactive glass, piezoelectric materials, temperature-responsive polymers and conductive inks all react to a stimulus — heat, light, an electrical signal or pressure — rather than staying fixed like traditional materials.
Shape-memory alloys are chosen where a product needs to change shape reliably without a motor, such as a fitting that tightens itself once warmed. Piezoelectric materials are chosen for sensors that must detect force, pressure or vibration, or for tiny actuators that need to move slightly when a small voltage is applied. Conductive inks let designers print circuits directly onto flexible, lightweight surfaces instead of using bulky wiring.
Composite Materials
A composite material is made by combining two or more materials so the finished material performs better than either ingredient alone. Concrete is a composite of cement, aggregate and water, giving a material with high compressive strength for construction. Plywood is a composite too — thin layers of wood veneer are glued together with the grain of each layer rotated, which spreads strength in more than one direction and stops the wood splitting easily.
A reinforced polymer is made by embedding fibres — glass, carbon or another fibre — inside a polymer resin. The fibres carry the load and the resin holds them in shape, giving a material that is both very strong and very light. This combination is why fibre-reinforced polymers turn up in products where weight matters as much as strength, from sports equipment to vehicle panels.
The specification also identifies robotic materials — composites developed so that a structure can sense its surroundings or respond automatically, rather than simply providing strength. Combining materials this way lets designers build responsiveness into the structure of a product itself, instead of adding a separate electronic system.
In a fibre-reinforced polymer, the fibres (glass or carbon) carry the structural load while the polymer resin binds them together, producing a material with a very high strength-to-weight ratio.
Technical Textiles
A technical textile is chosen for what it does, not how it looks. Agro-textiles protect crops and improve growing conditions, for example by covering plants against frost or pests. Construction textiles are used within buildings, such as membranes that keep water out of a roof while still letting it breathe. A geo-textile reinforces soil and stabilises the ground on projects such as road building or riverbank protection, stopping the earth from shifting or eroding.
Domestic textiles bring technical performance into the home, such as flame-resistant curtains. Environmentally friendly textiles are engineered specifically to reduce environmental impact, for example by being made from recycled or biodegradable fibres. A protective textile guards the wearer against a hazard like heat, sharp edges or impact, which is why they appear in workwear and safety clothing. Sports textiles are engineered to support performance during exercise, for example by moving moisture away from the skin or allowing the body to breathe.
A company is designing a knee support for athletes. A sports textile gives breathability and stretch against the skin, while a rigid section moulded from a fibre-reinforced polymer runs along the side of the joint to resist bending sideways. If the support also needed to loosen automatically once the knee had cooled after exercise, a shape-memory alloy strip could be built in to change shape with temperature. Combining several material types like this lets a single product meet several different performance requirements at once.