Micro-electro-mechanics of ionic polymeric gels as electrically controllable artificial muscles
- Univ. of New Mexico, Albuquerque, NM (United States)
A polymer gel is defined as a cross-linked polymer network swollen in a liquid medium. These gels possess an ionic structure in the sense that they are generally composed of a number of fixed ions pertaining to sites of various polymer cross-links and segments and mobile ions (counter ions) due to the presence of a solvent which is electrolytic. Ionic polymeric gels are three-dimensional networks of cross-linked macromolecular polyelectrolytes that swell or shrink in aqueous solutions on addition of alkali or acids, respectively. Linear reversible dilation and contraction of the order of more than 1,000 percent have been observed in the laboratory for polyacrylonitrile (PAN) fibers. Furthermore, it has been experimentally observed that swelling and shrinking of ionic gels can also be induced electrically. Thus, direct computer control of large expansions and contractions of ionic polymeric gels by means of a voltage gradient appears to be possible. A mechanism is presented for the reversible nonhomogeneous large deformations and in particular bending of strips of ionic polymeric gels in the presence of an electric field. Exact expressions are given relating the deformation characteristics of the gel to the electric field strength or voltage gradient, gel dimensions and other physical parameters such as the resistance and the capacitance of the gel strip. It is concluded that direct voltage control of such nonhomogeneous large deformations in ionic polymeric gels is possible. These electrically controlled deformations may find unique applications in robotics, artificial muscles, large motion actuator designs, drug delivery systems and smart materials, adaptive structures and systems.
- OSTI ID:
- 395230
- Report Number(s):
- CONF-940691--; ISBN 1-56676-171-9
- Country of Publication:
- United States
- Language:
- English
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