Smart and modern materials – thermochromic, photochromic, shape-memory alloy, graphene, metal foam, titanium, carbon fibre
Design & TechnologyMechanical EngineeringAges 16–17
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Sign in to playA virtual lab: heat or cool a thermochromic pigment, a thermochromic liquid crystal and a nitinol wire, and shine UV light on a photochromic lens; follow a time graph and record results in a table. Compare the density, strength, stiffness, electrical and thermal conductivity and cost of graphene, carbon nanotubes, carbon fibre composite, titanium alloy, aluminium foam and nitinol with aluminium and steel. Solve six design briefs by choosing a material and a component, with feedback on every requirement.
Lesson: Modern and smart materials: smart materials, nanomaterials and composites
What it shows
Smart materials change a property in response to a change in their surroundings and change back when it is removed. Thermochromic pigments change colour at a set temperature; photochromic pigments darken in ultraviolet light; a shape-memory alloy such as nitinol is bent when cool and returns to its remembered shape when heated above its transition temperature. Modern materials have been developed for high performance: graphene and carbon nanotubes are extremely strong and conductive at the nanoscale, carbon fibre composites and titanium alloys are strong for their weight, and metal foams are very light and absorb impacts.
How to use
On Lab, choose a Sample, set Plate temperature and UV lamp, and move Colour-change temperature or Transition temperature Af. Press Bend wire, then heat it. Press Record result to add a row to the table. On Compare materials, choose a Property and tap a bar. On Design brief, choose a Brief, a Main material and an Extra component.
Parameters you can change
- Screen Lab, Compare materials, Design brief
- Sample Thermochromic pigment, Thermochromic liquid crystal, Photochromic pigment, Shape-memory alloy wire (nitinol)
- Hot/cold plate temperature -10–100 °C
- UV lamp intensity 0–100 %
- Colour-change temperature of the pigment 15–45 °C
- Nitinol transition temperature Af 20–90 °C
- Simulation speed ×1 (real time), ×5, ×20
- Property to compare Density, Tensile strength, Stiffness (Young's modulus), Specific strength, Electrical conductivity, Thermal conductivity, Relative cost
- Design brief Bath-temperature duck, Light-adaptive glasses, Greenhouse vent opener, Racing bike frame, Car crash box, Foldable screen electrode
- Main material Thermochromic pigment in plastic, Photochromic pigment in clear plastic, Nitinol (shape-memory alloy), Graphene, Carbon nanotubes, Carbon fibre composite (CFRP), Titanium alloy, Aluminium foam, Aluminium alloy, Mild steel, Polycarbonate (plain plastic)
- Extra component None, Thermistor + LED + battery, Light sensor + LCD tint + battery, Thermistor + motor + battery, Steel return (bias) spring
Questions to explore
- Why does a nitinol greenhouse vent opener need a return spring to close the window again?
- Why do photochromic glasses darken less inside a car and on a hot day?
- Graphene is extremely strong, so why are bicycle frames not made from graphene?
