Materials that Move

Abstract

Kinetic materials range from well-known shape memory alloys to more “exotic” materials such as ferrogels and shape memory ceramics. The common characteristic of all these smart materials is their ability to undergo a predetermined shape change as a response to an external stimulus such as light, electricity, humidity, or heat. The shape change can be reversible or irreverbible. This chapter attempts to categorize kinetic materials according to two features: based on the material type (e.g. alloys, polymers, gels) and based on the stimulus they respond to (e.g. thermoresponsive, magnetostrictive, or electroactive). After explaining these categories, details of the most important kinetic materials are discussed. This chapter focuses mainly on the mechanismas that lead to a shape with an explanation of the underlying material science principles. Some key terms are defined and important properties of shape memory materials (alloys and polymers) are listed. A brief history on the discovery and development of certain kinetic materials is also presented.