Smart materials

Abstract

Building hardware that fit within the philosophy of Ambient Intelligence often requires access to responsive materials. For this purpose responsive materials are defined as materials that change appearance or shape as a function of an external stimulus. That may be as much as the way a person experiences the look of a material in its interaction with light related to addressable properties such as absorption (colour, brightness, transmission) and scattering (velvet tones, metallic, transmission). But it can also be related to other properties to trigger a person's perception of its ambient, such as surface roughness, odour release, acoustic reflection, etc. The driving force for the change in the material's property can be an electrical voltage or current as a response to a stimulus from a sensor. In that case the sensor picks up a signal from the environment it is in. Examples are the presence of a person, change in conditions such as temperature, humidity, ambient light, the use of audio-visual equipment, etc. But the response of the materials can also be more autonomous where it changes properties as a result of the dynamically changing environmental conditions without the intervention of an additional sensor.When integrated in commodities as furniture and electronic equipment or even in the walls of a building or in the interior or exterior of vehicles, one can speak of so-called smart-skins or electronic skins which draw much attention in the world of military equipment and in programs such as Ambient Intelligence.