Written by Grant England AP225, Fall 2011
Responsive materials are materials which change in response to environmental stimuli. Examples include hydrogels or other polymer gels (which can change size upon response to a stimulus), photochromic or thermochromic materials (which change color or opacity),piezoelectric or piezoresistive materials (which incur a voltage or resistivity change when stressed), light-emitting materials, and thermoelectric materials. They differ from active materials in that they cannot be changed programmably, but change only with response to environmental stimuli and usually require a finite amount of time to undergo the phase transition from one state to the other.
Responsive Material Applications
Responsive materials have applications that affect most of our everyday lives. Digital weight scales use piezoelectric strain gauges to determine weight. Transition (c) lenses use photochromic material to tint in response to UV light.
This powerpoint shows several examples of responsive "smart" materials.
By using materials which change shape or conformation upon environmental stimuli, self-cleaning surfaces can be created by using bio-inspired microfloret design which opens and closes to prevent biofouling.
Dow Corning has created a new fabric material which is pliable under normal conditions, but becomes rigid when applied to a stress.