Dt Gcse Revision: Smart Materials
A SMART material is a material that is affected by outside influence.
* Type of thermoplastic (can be reshaped many times). * Normally supplied in form of granules or small plastic beads. * Low fusing temperature of around 60°C. This means it can be reduced to a mouldable condition by immersion in hot water. * Once fused turns from opaque to clear. * Heating above 65°C is dangerous as it will become a sticky-adherent mass, similar to hot-melt glue. * Polymorph has high molecular weight and great tensile strength, and therefore suited for applications where mechanical strength is important. * Some uses are: Mould-making (i.e Gum-shields), general DIY materials, making a polymorph skeleton to support other materials, trainer/shoe components.
QTC (Quantum Tunnelling Composite) * QTC is a composite material made from conductive filler particles combined with an elastomeric binder, typically silicone rubber. * QTC Material has the unique ability to smoothly change from an electrical insulator to a metal-like conductor when placed under pressure. * While in an unstressed state the QTC Material is a near-perfect insulator; with any form of deformation the material starts to conduct and with sufficient pressure metallic conductivity levels can be achieved. * QTC™ Material can be formed or moulded into virtually any size, thickness or shape. * QTC™ Material is mechanically strong. * QTC™ Material can be made to withstand extreme temperatures limits. * Used for switches and keyboards.
Thermochromic Ink * These materials change colour when there is a change in temperature. * Thermochromic ink comes in two forms: Liquid crystals and Leuco dyes. * Leuco dyes are easier to work with and allow for a greater range of applications. * Applications of thermochromic ink include: flat thermometers, battery testers, clothing.