TABLE OF CONTENTS Leslie J. Shelton, Scott J. Woltman and Gregory P. Crawford
Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus impressis cogitur statum illum mutare.
An object at rest will remain at rest unless acted upon by an external and unbalanced force. An object in motion will remain in motion unless acted upon by an external and unbalanced force.
Newton s First Law of Motion
After examining technology like color mimicking, patterns and other fixed photonic biomimetic features, the next natural progression is the act of motion. In this chapter, more active materials that exhibit visible movement are presented. Devices capable of changing their own size, shifting their shapes, curling and uncurling, and even performing more elaborate motions like swimming in water are discussed. This chapter reviews actuation and delivery systems, with a primary focus on liquid crystalline and polymer materials. Actuators, in general, are devices capable of converting external stimuli (electric field, light, temperature, etc.) into mechanical motion; congruently, delivery systems also undergo physical shape changes in the presence of similar stimuli. The great variations in function and potential triggers give both systems a wide range of applications that span many scopes of medicine. Several types of liquid crystal based actuators have already been developed and many new biomedical applications are currently under investigation.
Actuators are a broad category of materials and devices capable of spontaneous or stimulated movement. This movement can be a curling or a lengthening and can...
