An A-to-Z guide to smart materials ...
Smart Materials: Emerging Markets for Intelligent Gels, Ceramics, Alloys, and Polymers is your guide to the world of smart materials. In one handy volume it will give you a hard-headed assessment of new applications and markets ... And brief you on important develop-ments related to dozens of materials in a wide range of categories, including:
· Piezoelectric materials - These ceramics or polymers are character-ized by a swift, linear shape change in response to an electric field. The electricity makes the material expand or contract almost instantly. The materials have potential uses in actuators that control chatter in precision machine tools, improved robotic parts that move faster and with greater accuracy, smaller microelectronic circuits in machines ranging from computers to photolithography printers, and health-monitoring fibers for bridges, buildings, and wood utility poles.
· Electrostrictive and magnetostrictive materials - This refers to the material quality of changing size in response to either an electric or magnetic field, and conversely, producing a voltage when stretched. These materials show promise in applications ranging from pumps and valves, to aerospace wind tunnel and shock tube instrumentation and landing gear hydraulics, to biomechanics force measurement for ortho-pedic gait and posturography, sports, ergonomics, neurology, cardiology, and rehabilitation.
· Rheological materials - Smart materials encompass not only solids but also fluids, electrorheological and magnetorheological fluids that can change state instantly through the application of an electric or magnetic charge. These fluids show promise in shock absorbers, dampers for vehicle seats and exercise equipment, and optical finishing.
· Thermoresponsive materials - Shape memory alloys, the dominant smart material, change shape in response to heat or cold. They are most commonly Nitinol, or nickel and titanium combined. Less popular but still possessing the shape memory effect are gold cadmium, silver cad-mium, copper-aluminum-nickel, copper tin, copper zinc, and copper zinc aluminum. They are useful in couplers, thermostats, automobile, plane and helicopter parts.
· pH-sensitive materials - The most interesting of these are indicators that change colors as a function of pH, and show promise in paints that change color when the metal beneath begins to corrode.
· Electrochromic materials - Electrochromism is defined as the ability of a material to change its optical properties when a voltage is applied across it. These materials are used as antistatic layers, electrochrome layers in LCDs (liquid crystal displays), and cathodes in lithium batteries.
· Fullerenes - Spherically caged molecules with carbon atoms at the corner of a polyhedral structure consisting of pentagons and hexagons. In one application of fullerenes as a smart material, they are embedded into sol-gel matrices to enhance optical limiting properties.
· Smart gels - Engineered response gels that shrink or swell by a factor of 1000, and that can be programmed to absorb or release fluids in response to almost any chemical or physical stimulus. These gels are used in many appli-cations in agriculture, food, drug delivery, prostheses, cosmetics, and chemical processing.
· And many more.