Abstract: Nerve scaffolds are described that include a tubular outer housing fabricated from a biocompatible polymer, within which are disposed a plurality of carbon nanofiber yarns. The carbon nanofiber yarns, which can be separated by distances roughly corresponding to an average nerve fiber diameter, provide surfaces on which nerve fibers can regrow. Because the proximate carbon nanofiber yarns can support individual nerve fibers, a nerve can be regenerated with a reduced likelihood of undesirable outcomes, such as nerve pain or reduced nerve function.

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.

Abstract: A fabric of nanofibers that includes an adhesive is described. The nanofibers can be twisted or both twisted and coiled prior to formation into a fabric. The adhesive can be selectively applied to or infiltrated within portions of the nanofibers comprising the nanofiber fabric. The adhesive enables connection of the nanofiber fabric to an underlying substrate, even in cases in which the underlying substrate has a three-dimensional topography, while the selective location of the adhesive on the fabric limits the contact area between the adhesive and the nanofibers of the nanofiber fabric. This limited contact area can help preserve the beneficial properties of the nanofibers (e.g., thermal conductivity, electrical conductivity, infra-red (IR) radiation transparency) that otherwise might be degraded by the presence of adhesive.

Abstract: A fabric of nanofibers that includes an adhesive is described. The nanofibers can be twisted or both twisted and coiled prior to formation into a fabric. The adhesive can be selectively applied to or infiltrated within portions of the nanofibers comprising the nanofiber fabric. The adhesive enables connection of the nanofiber fabric to an underlying substrate, even in cases in which the underlying substrate has a three-dimensional topography, while the selective location of the adhesive on the fabric limits the contact area between the adhesive and the nanofibers of the nanofiber fabric. This limited contact area can help preserve the beneficial properties of the nanofibers (e.g., thermal conductivity, electrical conductivity, infra-red (IR) radiation transparency) that otherwise might be degraded by the presence of adhesive.

Abstract: A composite including a heat conformable polymer and a nanofiber sheet is disclosed. The heat conformable polymer can be a hot melt adhesive, and the combination can provide an electrically conductive hot melt adhesive composite. The nanofiber layer is protected and the composite is conformable and/or can be adhered to a variety of surfaces.

Abstract: Actuators (artificial muscles) comprising twist-spun nanofiber yarn or twist-inserted polymer fibers generate torsional actuation when powered electrically, photonically, chemically, thermally, by absorption, or by other means. These artificial muscles utilize coiled yarns/polymer fibers and can be either neat or comprising a guest. In some embodiments, the actuator system includes a twisted and coiled polymer fiber actuator, and at least one of (i) wire connections that enable electrical heating of the twisted and coiled polymer fiber actuator, (ii) a radiation source and radiation pathway that enables photothermal heating of the twisted and coiled polymer fiber actuator, and (iii) a delivery system for delivering chemicals whose reaction produces heating of the twisted and coiled polymer fiber actuator.

Abstract: Actuators (artificial muscles) comprising twist-spun nanofiber twist-inserted polymer fibers generate tensile actuation when powered electrically, photonically, chemically, thermally, by absorption, or by other means. These artificial muscles utilize coiled polymer fibers and can be either neat or comprising a guest. In some embodiments, the coiled polymer fibers actuator can be incorporated into an article, such as a textile, braid, clothing, smart packaging, or a mechanical system, and the coiled polymer fiber in the coiled polymer fiber actuator can have a stroke amplification factor of 5 or greater.

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: A nanofiber sheet dispenser that houses a nanofiber forest from which a nanofiber sheet can be drawn is described. Using the nanofiber sheet dispenser, a nanofiber forest disposed on a substrate can be moved, transported, and/or shipped with a reduced risk of damage relative to transporting a nanofiber sheet. Techniques are also described for configuring the nanofiber sheet dispenser so that a nanofiber sheet can be conveniently drawn from the forest and, in some cases, drawn so as to form a nanofiber yarn that is continuous with both the nanofiber sheet and the nanofiber forest, the latter of which is within the nanofiber sheet dispenser.

Abstract: A fabric of nanofibers that includes an adhesive is described. The nanofibers can be twisted or both twisted and coiled prior to formation into a fabric. The adhesive can be selectively applied to or infiltrated within portions of the nanofibers comprising the nanofiber fabric. The adhesive enables connection of the nanofiber fabric to an underlying substrate, even in cases in which the underlying substrate has a three-dimensional topography, while the selective location of the adhesive on the fabric limits the contact area between the adhesive and the nanofibers of the nanofiber fabric. This limited contact area can help preserve the beneficial properties of the nanofibers (e.g., thermal conductivity, electrical conductivity, infra-red (IR) radiation transparency) that otherwise might be degraded by the presence of adhesive.

Abstract: Actuators (artificial muscles) comprising twist-spun nanofiber yarn or twist-inserted polymer fibers generate torsional actuation when powered electrically, photonically, chemically, thermally, by absorption, or by other means. These artificial muscles utilize coiled yarns/polymer fibers and can be either neat or comprising a guest. In some embodiments, the torsional fiber actuator includes a first polymer fiber (exhibiting a first polymer fiber diameter) and a torsional return spring in communication with the first polymer fiber. The first polymer fiber is configured to include a first plurality of twists in a first direction to produce a twisted polymer fiber. The first polymer fiber is further configured to include a plurality of coils in the twisted polymer fiber in a second direction each coil having a mean coil diameter.

Abstract: Placement of nanofibers and yarns comprised of nanofibers onto a substrate are described. The nanofiber yarns are difficult to manipulate with precision given that the diameters can be as little as 5 microns or even less than one micron. As described herein, a placement system is described that can place nanofiber yarns on a substrate at pitches less than 100 ?m, less than 50 ?m, less than 10 ?m, and in some embodiments as low as 2 ?m. In part, this precise placement at small pitches is facilitated by the use of coarse and fine adjustment translators, and a guide connected to a compliant flange. The compliant flange and the guide facilitate consistency of location of a nanofiber yarn.

Abstract: Nerve scaffolds are described that include a tubular outer housing fabricated from a biocompatible polymer, within which are disposed a plurality of carbon nanofiber yarns. The carbon nanofiber yarns, which can be separated by distances roughly corresponding to an average nerve fiber diameter, provide surfaces on which nerve fibers can regrow. Because the proximate carbon nanofiber yarns can support individual nerve fibers, a nerve can be regenerated with a reduced likelihood of undesirable outcomes, such as nerve pain or reduced nerve function.

Abstract: Nerve scaffolds are described that include a tubular outer housing fabricated from a biocompatible polymer, within which are disposed a plurality of carbon nanofiber yarns. The carbon nanofiber yarns, which can be separated by distances roughly corresponding to an average nerve fiber diameter, provide surfaces on which nerve fibers can regrow. Because the proximate carbon nanofiber yarns can support individual nerve fibers, a nerve can be regenerated with a reduced likelihood of undesirable outcomes, such as nerve pain or reduced nerve function.

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: An insulated nanofiber having a continuous nanofiber collection extending along a longitudinal axis with an outside surface and an inside portion is described. A first material infiltrates the inside portion, where the outside surface of the nanofiber collection is substantially free of the first material. An electrically-insulating second material coats the outside surface of the nanofiber collection. A method of making an insulated nanofiber collection is also disclosed.

Abstract: Techniques are described for infiltrating a nanofiber yarn with an infiltration material and removing a surface layer of the infiltration material on at least a portion of the infiltrated nanofiber yarn. This enables an infiltration method by which the infiltration material is selectively disposed within an interior of a nanofiber yarn and not disposed on an exterior surface of at least a portion of a nanofiber yarn. Electrical connection can be established by mechanically connecting an electrode (e.g., a conductive clamp or fitting) directly to the exposed surface of the nanofiber yarn.

Abstract: A density of a nanofiber sheet can be changed using an edged surface, and in particular an arcuate edged surface. As described herein, a nanofiber sheet is drawn over (and in contact with) an arcuate edged surface. Depending on whether the arcuate surface facing a direction opposite the direction in which the nanofiber sheet is being drawn is convex or concave determines whether the nanofiber sheet density is increased relative to the as-drawn sheet or decreased relative to the as-drawn sheet.

Abstract: A flexible sheet comprising a composite sheet, the composite sheet comprising a binder and an aggregate containing a plurality of carbon nanotubes that is disposed in the binder, wherein the aggregate is formed as a waveform structure travelling along a single direction in a plane of the composite sheet, is provided. The disclosed flexible sheets may be used as thermally conductive components, electrically conductive components, antistatic components, electromagnetic wave shields, and/or heating elements, in addition to other possible uses.

Abstract: Nanofiber based sensors are described that can be used to detect analytes in biological or non-biological contexts. Each sensor includes at least two nanofiber yarns that are spaced apart from one another so as to avoid electrical (or physical) contact. Each nanofiber yarn of the nanofiber sensor includes a sensing region that is in electrical contact with the rest of the corresponding nanofiber yarn. The sensing regions of the at least two nanofibers are treated with complementary sensing agents so that when the sensing regions (and the corresponding sensing agents) are exposed to the analyte to be detected, an electrical response is detected. This response is then communicated through one or more of the nanofiber yarns for interpretation by a processor.