Massachusetts Institute of Technology

Other

John D Madden

Ian W Hunter

Serge R Lafontaine

Tanya S Kanigan

A method for driving an actuator. The method includes applying an electrical potential across an electrostrictive material relative to a counterelectrode disposed within an electrolyte, thereby creating a double layer potential across a region of enhanced ionic concentration. A current flowing between the electorostrictive material and the counterelectrode is measured. A portion of the applied potential appearing across the electrolyte and counterelectrode is calculated and subtracted from the applied potential to obtain an estimated double layer potential. The applied electrical potential is adjusted to obtain a specified double layer potential.

High power-to-mass ratio actuator

Embodiments of actuators having an active member including a polymer having a surface, an electrolyte coupled to the surface, and an electrolyte are provided. Actuators which, when an electrical potential is applied across the electrolyte between the active member and the counter electrode, exert force per unit area of at least 10 MPa are described. Particular designs utilizing stretch aligned conducting polymers as active members are discussed.

Conducting polymer actuator

A method for generating electricity is provided utilizing a conducting polymer, an electrolyte and a counterelectrode and applying mechanical work to the polymer thereby generating an electrical potential between the conducting polymer and the counterelectrode. Coupling of the electrical potential is then made to an external circuit. The resultant mechanical to electrical energy conversion efficiency is at least 0.01%. Also provided is a method for braking a mechanical member by utilizing a conducting polymer, coupling it to the mechanical member, generating an electrical potential between the conducting polymer and a counterelectrode and coupling the electrical potential to an external circuit. The step of coupling may include dissipating and/or storing electrical energy in the external circuit. The conducting polymer provided may preferably be polypyrrole. In another embodiment, a brake for the mechanical member is provided.

Conducting polymer generator-actuator with energy storage/recovery

A rotary actuator for applying torque to a crank with respect to a member. The rotary actuator has a substantially planar sheet of anisotropic conducting polymer, portions of which are activated in temporal sequence to produce rotation of the crank with respect to the axis of the crank. Actuation is achieved by contraction of successive portions of the sheet as electrical current causes differential strain in the sheet.

Conducting polymer driven rotary motor

Embodiments of the present invention provide a new method for producing a three dimensional object, particularly suited to microfabrication applications. The method includes the steps of providing a substrate with a conducting interface, an electrode having a feature or features that are small relative to the substrate, and a solution. The solution has a reactant that will either etch the substrate or deposit a selected material in an electrochemical reaction. The electrode feature is placed close to but spaced from the interface. A current is passed between the electrode and the interface, through the solution, inducing a localized electrochemical reaction at the interface, resulting in either the deposition of material or the etching of the substrate. Relatively moving the electrode and the substrate along a selected trajectory, including motion normal to the interface, enables the fabrication of a three dimensional object. In an alternative embodiment, current is passed through an orifice placed close to but spaced from the substrate surface, and may be accompanied by forced convection through the orifice. The method provides the potential to fabricate using many materials, including metals, alloys, polymers and semiconductors in three dimensional forms and with sub-micrometer spatial resolution.

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Somerville, MA, United States of America

John D Madden