Abstract: A multilayer composite is disclosed comprising a heat shrinkable polymer layer and a nanofiber layer. Methods of forming the composite and uses thereof are also described.

Abstract: Methods and systems are described for continuously densifying at least one nanofiber sheet using heat and an applied force that can include both compressive and tensile components. Nanofiber sheets densified using these techniques have a more uniform and more highly aligned microstructure than nanofiber sheets densified using a solvent alone. As a result, the nanofiber sheets of the present disclosure have, for example, higher tensile strength and better electrical conductivity than nanofiber sheets densified using other techniques.

Abstract: A nanofiber forest that includes a pattern or shape can be transferred to a substrate. The nanofiber forest can be configured to have any perimeter and/or internal shape or pattern using a stencil technique and/or using an engraving technique. This pattern can be transferred as a “negative image” of a corresponding pattern in a stencil or as a “positive image” by engraving the pattern directly into the nanofiber forest. For either type of pattern formation, the patterned nanofiber forest is transferred by applying a substrate to the pattern or to a nanofiber forest covered by a patterned stencil. Pressure is then applied causing the exposed surface of the nanofiber forest or pattern of nanofiber forest to adhere to the substrate.

Abstract: Thermochromic displays that accomplish a thermochromic transition in less than 100 milliseconds are described. This rapid response time is accomplished by including conductive structures within the thermochromic display and placing the conductive structures in direct contact with and/or proximate to a thermochromic layer. The conductive structures can be disposed between the thermochromic layer and a film that carries the message to be produced. Because of the high thermal conductivity of the conductive structures, heat can be conducted to and/or conducted away from the thermochromic layer much more rapidly than in the absence of conductive structures.

Abstract: Apparatuses and methods for manufacturing an apparatus for supplying a sweeping motion for a device such as a camera are disclosed. The apparatus includes a stationary rod and a rotational rod arranged parallel to the stationary rod at a fixed distance from the stationary rod. The apparatus includes a device disposed on the rotational rod and a plurality of linear artificial muscle actuators arranged between the stationary and rotational rods and perpendicular to central axes of the stationary and rotational rods. Actuation of a top-portion of the plurality of linear artificial muscle actuators rotates the rotational rod in a first direction, and an actuation of a bottom-portion of the plurality of linear artificial muscle actuators rotates the rotational rod in a second direction opposite to the first direction.

Abstract: A hinge-type actuator device in accordance with the present disclosure may include a first and second paddle, a first and second artificial muscle actuator segment, and a plurality of contacts, where the first and second artificial muscle actuator segments are actuated via the contacts, actuation of the first artificial muscle actuator segment causes the first and second paddle to open the hinge-type actuator, and actuation of the second artificial muscle actuator segment causes the first and second paddle to dose the hinge-type actuator.

Abstract: Techniques are described for transferring nanofiber forests using transfer films that either lack a conventional adhesive at the substrate—nanofiber forest interface or that include a diffusion barrier that prevents diffusion of adhesive molecules (or other polymer molecules mobile at ambient temperatures) into the nanofiber forest. These techniques can be applied to single layer nanofiber forests or stacks of multiple nanofiber forest. By selecting the bond strength between the nanofiber forest and the transfer films, the nanofibers can be aligned in a common direction that includes, but is not limited to, perpendicular to a substrate or transfer film.

Abstract: An actuator includes a plurality of artificial muscle fibers and at least one conducting material. The at least one conducting material electrically stimulates the plurality of artificial muscle fibers during activation of the actuator. An actuator device includes at least one artificial muscle fiber and at least one high-strength creep-resistant fiber.

Abstract: A method for manufacturing a separable artificial muscle fastener includes: securing one or more muscle loops of an artificial muscle fiber to a substrate such that at least a portion of the one or more muscle loops extends out from the substrate; annealing the artificial muscle fiber to retain the one or more muscle loops; and cutting and removing a portion of the one or more muscle loops to transform the one or more muscle loops into one or more muscle hooks. When the one or more muscle hooks are engaged with one or more holders, actuating the one or more muscle hooks disengages the one or more muscle hooks from the one or more holders.

Abstract: An actuating device and a method for manufacturing an actuating device, where the method includes wrapping a conductive wire (204) around a polymer fiber (202) at a set tension, and heating the polymer fiber and wire to a temperature that exceeds the glass transition temperature of the polymer fiber for a predetermined amount of time to partially embed the conductive wire into the polymer fiber. The method also includes cooling the polymer fiber and wire to below the glass transition temperature resulting in a wired polymer fiber wherein at least part of the conductive wire is embedded in the polymer fiber.

Abstract: Systems for fabricating nanofiber yarn at rates of at least 30 m/min (1.8 kilometers (km)/hour (hr)) using a “false twist” nanofiber yarn spinner and a false twist spinning technique are disclosed. In a false twist spinning technique, a twist is introduced to nanofibers in a strand by twisting the nanofibers at points between ends of the strand. This is in contrast to the “true twist” technique where one end of a strand is fixed and the opposing end of the strand is rotated to introduce the twist to intervening portions of yarn.

Abstract: A hinge-type actuator device in accordance with the present disclosure may include a first and second paddle, a first and second artificial muscle actuator segment, and a plurality of contacts, where the first and second artificial muscle actuator segments are actuated via the contacts, actuation of the first artificial muscle actuator segment causes the first and second paddle to open the hinge-type actuator, and actuation of the second artificial muscle actuator segment causes the first and second paddle to close the hinge-type actuator.

Abstract: Techniques are described for controlling widths of nanofiber sheets drawn from a nanofiber forest. Nanofiber sheet width can be controlled by dividing or sectioning the nanofiber sheet in its as-drawn state into sub-sheets as the sheet is being drawn. A width of a sub-sheet can be controlled or selected so as to contain regions of uniform nanofiber density within a sub-sheet (thereby improving nanofiber yarn consistency) or to isolate an inhomogeneity (whether a discontinuity is the sheet (e.g., a tear) or a variation in density) within a sub-sheet. Techniques for dividing a nanofiber sheet into sub-sheets includes mechanical, corona, and electrical arc techniques.

Abstract: Polymer and nanotube-based actuators that include a thermochromic coating is disclosed. The actuators include a thermochromic material applied to a surface of the core fiber or the conductive element. Upon heating the actuator, the thermochromic coating undergoes a color transition to indicate a pre-determined temperature correlated to a rated critical temperature, important temperature of the actuator components, or a level of actuation.

Abstract: An actuator device that includes a first fiber, a conducting material, and a coating. The coating coats the first fiber or the conducting material. The coating may also provide moisture protection, UV protection, thermal insulation and thermal conductivity.

Abstract: One or more nanofiber yarns can be placed in contact with one or more nanofiber sheets. The nanofiber yarns, which include single-ply and multi-ply nanofiber yarns, provide added mechanical stability to a nanofiber sheet that decreases the likelihood of a nanofiber sheet wrinkling, folding, or otherwise becoming stuck to itself. Furthermore, the nanofiber yarns integrated with the nanofiber sheet can also act as a mechanism to prevent the propagation of tears through the nanofiber sheet. In some cases, an infiltrating material can be infiltrated into interstitial spaces defined by the nanofibers within both the nanofiber yarns and the nanofiber sheets. The infiltrating material can then form a continuous network throughout the nanofiber yarns and the nanofiber sheet.

Abstract: Examples described include composite nanofibers sheets that have been “infiltrated” with a polymer (i.e., the polymer has flowed past a surface of the nanofiber sheet and into at least some of spaces within the sheet defined by the nanofibers). An adhesive nanofiber tape is formed when the infiltrating polymer is an adhesive and the adhesive infiltrates the nanofiber sheet from a one major surface of the nanofiber sheet. In other described examples, some portions of nanofibers in the sheet have been conformally coated with at least one metal layer.

Abstract: An actuator device that includes a first actuating segment of an artificial muscle fiber, where one end of the first actuating segment is connected to a first terminal and the other end of the first actuating segment is connected to a second terminal. The device also includes a second actuating segment of an artificial muscle fiber, where one end of the second actuating segment is connected to a third terminal and the other end of the second actuating segment is connected to a fourth terminal. The device also includes a paddle disposed on both the first and second actuating segments and a heating provision disposed on the first and second actuating segments. The heating provision independently provides energy in the form of heat to the first and second actuating segments, and the actuator device moves rotates the paddle to a desired position through activating the first or second actuating segments.

Abstract: A triboelectric generator include at least two yarns, one of which has been infiltrated with a material having a positive triboelectric affinity and one of which has been infiltrated with a material having a negative triboelectric affinity. The at least two yarns are threaded through holes within a disk so that both of the yarns are disposed on both sides of the disk and pass through the holes within the disk. The at least two yarns are helically wrapped (or “coiled”) together on both sides of the disk. During uncoiling, the moving contact between the two yarns, infiltrated with materials having opposite triboelectric affinities, causes an electrical charge to develop. The generated electrical charge can be conducted away for use as electricity.

Abstract: A dispenser is described for dispensing nanofiber yarns that includes a housing that defines an inlet, an outlet, and a chamber. A spool, around which is wound a length of nanofiber yarn, is disposed within the chamber defined by the housing. The nanofiber yarn is threaded from the chamber through the outlet and can be dispensed in a controlled way that reduces the likelihood of developing knots within the nanofiber yarn, and which facilitates convenient application of the yarn onto an underlying surface. In some cases, the dispenser can be used to concurrently dispense an adhesive or other polymer along with the nanofiber yarn.