ABSTRACT
Smart materials are materials that respond to their environments in a timely manner. Smart materials can receive, transmit, or process a stimulus and respond by producing a useful eff ect that may include a signal that the materials are acting upon it. Some of the stimuli that may act upon these materials are strain, stress, temperature, chemicals (including pH stimuli), electric fi eld, magnetic fi eld, hydrostatic pressure, diff erent types of radiation, and other forms of stimuli. Another important criterion for a smart material is its ability to receive stimuli and responding to the stimuli to produce a useful eff ect that is and it must be reversible. Another feature that is an important factor in determining if a material is smart pertains to its asymmetrical nature. From the purist point of view, materials are smart if at some point within their performance history, they act reversible to a stimulus. Materials that formally had the label of being smart include piezoelectric materials,
electrostrictive materials, electrorheological materials, magnetorheological materials, thermoresponsive materials, pHsensitive materials, UV-sensitive materials, smart polymers, smart gels (hydrogels), smart catalysts, and shape memory alloys [1]. With the progress experienced by smart materials and the successful introduction of nanotechnology, a new class of smart materials has been developed. Th is class consists of the smart adhesives.
