US 5,334,629 A · Control of continuous phase pH using visible light to activate pH-dependent fibers and gels in a controlled and reversible manner

Abstract

A transparent polyelectrolyte fiber or gel, such as cross-linked polyacrylic acid, which contracts and expands upon the addition of an acid or base to an aqueous medium solution, is placed in the same solution with a pH dependent dye, a colored photochromatic indicator dye. The dye preferably has a pA.sub.a value that is the same as the pH at a null contraction point of the fiber. By irradiating the solution with light of a wavelength of the absorption band of either the acid or base form of the dye, the solution pH is made to change, and the fiber is made to expand or contract, depending upon the wavelength. Thus, light energy is readily converted to work energy and may be used to power a pump, for example, or an artificial muscle can be powered via an optical fiber.

Claims60

Dependent claims

A visible light actuated apparatus comprising:

a source of visible light having the capability of selectively emitting either of at least one first wavelength of visible light or at least one second wavelength of visible light, said at least one first wavelength of visible light and said at least one second wavelength of visible light being emitted within the spectrum of visible light of between 400 nm to 700 nm and at an amplitude sufficient to effect a pH change;
a pH dependent dye solution, disposed to receive said at least one first wavelength of visible light or said at least one second wavelength of visible light, having the property of being responsive to said at least one first wavelength of visible light or said at least one second wavelength of visible light to change its pH to either of two discrete pH values within a pH range of 3 to 11, respectively;
and
a polyelectrolyte fiber, disposed in said pH dependent dye solution, having the property to change its volume in response to one of said two discrete pH values of said pH dependent dye solution to produce a selective first physical displacement and to reversibly change its volume in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement.

1 more element

A method actuated by visible light comprising:

radiating at least one first wavelength of visible light or at least one second wavelength of visible light from a source of at least one first wavelength of visible light and at least one second wavelength of visible light, said at least one first wavelength of visible light and said at least one second wavelength of visible light being emitted within the spectrum of visible light of between 400 nm to 700 nm and at an amplitude sufficient to effect a pH change;
providing a pH dependent dye solution, disposed to receive said at least one first wavelength of visible light or said at least one second wavelength of visible light, having the property of being responsive to said at least one first wavelength or said at least one second wavelength of visible light to change its pH within a pH range of 3 to 11;
immersing a polyelectrolyte fiber in said pH dependent dye solution, said polyelectrolyte fiber having the property to change its volume in response to one of said two discrete pH values of said pH dependent dye solution to produce a selective first physical displacement and to reversibly change its volume in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement;
directly radiating said at least one first wavelength of visible light or said at least one second wavelength of visible light from said source of said at least one first wavelength of visible light and said at least one second wavelength of visible light to impinge on said pH dependent dye solution;
changing the pH in said pH dependent dye solution to one of said two discrete pH values by said directly radiating;
changing the volume of said polyelectrolyte fiber in response to said one of said two discrete pH values to produce a selective first physical displacement;
changing the pH in said pH dependent dye solution to the other of said two discrete pH values by said directly radiating;
and
reversibly changing the volume of said polyelectrolyte fiber in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement.

6 more elements

An apparatus for pumping a fluid in response to visible light comprising:

a source of visible light having the capability of selectively emitting either of at least one first wavelength of visible light or at least one second wavelength of visible light, said at least one first wavelength of visible light and said at least one second wavelength of visible light being emitted within the spectrum of visible light of between 400 nm to 700 nm and at an amplitude sufficient to effect a pH change;
means for defining a first chamber and a second chamber having a displaceable wall in communication with at least one of the chambers, the defining means being provided with a portion transparent to said at least one first wavelength of visible light and at least one said second wavelength of visible light and being further provided with at least one check valve arranged in communication with said second chamber to assure a pumping of said fluid in response to said selective displacement of said displaceable wall;
a pH dependent dye solution, disposed in said first chamber to receive said at least one first wavelength of visible light or at least one said second wavelength of visible light, having the property of being responsive to said at least one first wavelength of visible light or said at least one second wavelength of visible light to change its pH to either of two discrete pH values within a pH range of 3 to 11, respectively;
and
a polyelectrolyte fiber, disposed in said pH dependent dye solution and coupled to said displaceable wall, said polyelectrolyte fiber having the property to change its volume in response to one of said two discrete pH values of said pH dependent dye solution to produce a selective first physical displacement of said wall and to reversibly change its volume in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement of said wall.

2 more elements