Patent Number: 053346297
Section: summary

BACKGROUND OF THE INVENTION Synthetic (plastic) fibers which contract and expand upon stimulation with acid, heat, electrical current and light have been known for some time, see the article by Y. Osada, entitled "Conversion of Chemical into Mechanical Energy by Synthetic Polymers," Adv. in Polym. Sci 82, Springer Verlag, Berlin, Heidelberg, 1987. However, a good mimic of the human or animal muscle by a natural or synthetic fiber has been difficult to say the least since there has been no way to distribute the muscle-activating energy quickly to the fibers to enable responsive motion. Thus, a continuing need exists in the state of the art for a means of supplying activating energy to natural or synthetic fibers, such as polyelectrolyte fibers or gels, which respond to pH changes in a pH dependent solution by changing their volume, thereby enabling the fibers to do work in response to selected wavelengths of impinging electromagnetic radiation. SUMMARY OF THE INVENTION The present invention is directed to providing an apparatus for and method of radiation-actuation of a polyelectrolyte fiber or gel. A pH dependent dye solution is responsive to discrete incident radiation to change its pH. A polyelectrolyte fiber or gel disposed in the pH dependent dye solution has the property to change its volume in response to pH changes in the pH dependent dye solution. A source of the discrete incident electromagnetic radiation is oriented to direct the discrete incident electromagnetic radiation on the pH dependent dye solution and polyelectrolyte fiber or gel to effect a change in pH in the pH dependent dye solution and a consequent change in volume in the polyelectrolyte gel. An object of the invention is to provide an apparatus for and a method of selective electromagnetic radiation actuation of a polyelectrolyte fiber or gel. An object is to provide an apparatus for and a method of selective electromagnetic radiation actuation of a polyelectrolyte fiber or gel that minimizes heat production. Another object is to provide an apparatus for and a method of selective actuation of a polyelectrolyte fiber or gel by discrete wavelengths of electromagnetic radiation to cause a responsive expansion and/or contraction thereof. Yet another object is to provide an apparatus for and a method of a responsive polyelectrolyte fiber actuation that changes the pH of a pH dependent dye solution by select wavelengths of electromagnetic radiation. Another object is to provide an apparatus for and a method of fiber actuation by select wavelengths of electromagnetic radiation that changes the pH of a pH dependent dye solution to responsibly and reversibly contract or expand substantially all of an immersed polyelectrolyte fiber simultaneously. Another object of the invention is to provide an apparatus for and a method of the selective expansion and contraction of a polyelectrolyte fiber by impinging select wavelengths of electromagnetic radiation that avoids the need for adding acid or base solutions. Another object is to provide an apparatus for and a method of a substantially delay-free actuation of a natural or synthetic polyelectrolyte fiber by impinging select wavelengths of electromagnetic radiation to avoid the need for a diffusion of hydrogen or hydroxide ions in individual fiber sites. Another object is to provide actuators of both great strength and tactile sensitivity to enable the fabrication of working robots or prosthetic devices. These and other objects of the invention will become more readily apparent from the ensuing specification and claims when taken in conjunction with the appended drawings.