Read the following text and fill in the gaps. Use the words given in boxes:
| temperature materials types magnetic properties
|
Smart materials are (1) __________ that have one or more (2) __________ that can be significantly changed in a controlled manner by external stimulation, such as stress, (3)__________, moisture, pH, electric or (4) __________ fields.
There are different (5) __________ of smart materials, some of which are already common. Some examples are as following:
| environment produce changes field from shape
|
- Piezoelectric materials are materials that (6) __________ a voltage when stress is applied. Suitably designed structures made (7) __________ these materials can bent, expand or contract when a voltage is applied.
- Shape memory alloys and shape memory polymers are thermo-responsive materials where deformation can be seen in case of temperature (8) __________.
- Magnetic shape memory alloys are materials that change their (9) __________ in response to a significant change in the magnetic (10) __________.
- pH-sensitive polymers are materials which collapse when the pH of the (11) __________ changes.
- Temperature-responsive polymers are materials which changes depend on temperature.
| pressure metal opacity colour sunlight response electrical
|
- Halochromic materials are commonly materials that change their colour as a result of changing acidity. One suggested application is for paints that can change (12) __________ to indicate corrosion in the (13) __________ underneath them.
- Chromogenic systems change colour in response to (14) __________, optical or thermal changes. These include electrochromic materials, which change their colour or (15) __________ on the application of a voltage (e.g. liquid crystal displays), thermochromic materials change in colour depending on their temperature, and photochromic materials, which change colour in response to light - for example, light sensitive sunglasses darken when used in bright (16) __________.
- Non-Newtonian fluid is a liquid which changes its viscosity in response to an applied shear rate (to shear = to become twisted or break under pressure). In other words the liquid will change its viscosity in (17) __________ to some sort of force or (18) __________.
- Ferrofluid
- Photomechanical Materials change shape under exposure to light.
