Smart Materials and Structure
Smart materials are designed materials that have one or more properties that can be significantly changed in a controlled fashion by external stimuli, such as stress, temperature, moisture, pH, electric or magnetic fields.
Other keywords related to smart material are such as shape memory material (SMM) and shape memory technology (SMT).
There are a number of types of smart material, some of which are already common. Some examples are as follows:
This are materials that produce a voltage when stress is applied. Since this effect also applies in a reverse manner, a voltage across the sample will produce stress within the sample. Suitably designed structures made from these materials can, therefore, be made that bend, expand or contract when a voltage is applied.
Shape-memory alloys and shape-memory polymers
Shape-memory alloys and shape-memory polymers are materials in which large deformation can be induced and recovered through temperature changes or stress changes (pseudoelasticity). The large deformation results due to martensitic phase change.
Magnetostrictive materials exhibit a change in shape under the influence of a magnetic field and also exhibit a change in their magnetization under the influence of mechanical stress.
Magnetic shape memory alloys
Magnetic shape memory alloys are materials that change their shape in response to a significant change in the magnetic field.
pH-sensitive polymers are materials that change in volume when the pH of the surrounding medium changes.
- Temperature-responsive polymers are materials which undergo changes upon temperature.
- Halochromic materials are commonly used materials that change their color as a result of changing acidity. One suggested application is for paints that can change color to indicate corrosion in the metal underneath them.
Photomechanical materials change shape under exposure to light.