Smart materials

Materials with adaptive capabilities that react to external stimuli such as load, heat, and vibrations. Examples of smart materials include self-healing concrete which releases reserves of a strong adhesive when under stress, mending cracks; shape-memory alloys and polymers which can undergo and reverse deformation by heat or stress thanks to pseudoelasticity; or chromogenic systems which change their color, such as sun glasses that darken when exposed to bright sunlight.