The University of Texas System

Ali E Aliev

Ray H Baughman

Shaoli Fang

Anvar A Zakhidov

Mei Zhang

Sergey Li

Chris Williams

Kenneth Ross Atkinson

Marcio Dias Lima

Mikhail E Kozlov

Carter Sebastian Haines

Na Li

Jiyoung Oh

Raquel Ovalle-Robles

Jiuke Mu

Zunfeng Liu

Zhong Wang

Run Wang

A dry-state non-contact method for patterning of nanostructured conducting materials is disclosed. Short self-generated electron-emission pulses in air at atmospheric pressure can enable an electron-emission-based (field enhancement) interaction between a sharp tungsten tip and elements of the nanostructured materials to cause largely non-oxidative sequential decomposition of the nanostructured elements. Embodiments can employ a substrate/tip gap of 10 to 20 nm, discharge voltages of 25-30 V, and patterning speeds as fast as 10 cm/s to provide precisely patterned nanostructures (&#x3c;200 nm) that are largely free of foreign contaminants, thermal impact and sub-surface structural changes.

Shaping nanomaterials by short electrical pulses

Cooling by a twist-untwist process, by a stretch-release process for twisted, coiled, or supercoiled yarns or fibers, and methods and systems thereof. High mechanocaloric cooling results from release of inserted twist or from stretch release for twisted, coiled, or supercoiled fibers, including natural rubber fibers, NiTi wires, and polyethylene fishing line. Twist utilization can increase cooling and cooling efficiencies. A cooler using twist insertion and release can be shorter and smaller in volume than a cooler that requires a large elastomeric elongation. The cooler system can be utilized in mechanochromic textiles and remotely readable tensile and torsional sensors.

Methods for torsional refrigeration by twisted, coiled, and supercoiled fibers and systems thereof

A nanofiber yarn that includes a plurality of nanofibers twisted into a yarn along an alignment axis. The nanofibers of the plurality of nanofibers have a ratio of nanofiber length to nanofiber circumference of at least 50. The yarn has a helix angle measured relative to the alignment axis of from 5&#xb0; to 30&#xb0;. The yarn has tensile strength of at least 280 MPa. A nanofiber fabric that includes a first sheet of multiwalled nanotubes and a second sheet of multiwalled nanotubes on the first sheet of multiwalled nanotubes. The multiwalled nanotubes of the first sheet are aligned in a first direction. The multiwalled nanotubes of the second sheet are aligned in the first direction. The first sheet and the second sheet are aligned so that the multiwalled nanotubes of the first sheet and the second sheet are both aligned in the first direction.

Fabrication and application of nanofiber ribbons and sheets and twisted and non-twisted nanofiber yarns

A process of producing a yarn, ribbon or sheet that includes nanofibers in which the process includes forming a yarn, ribbon or sheet comprising nanofibers, and applying an enhancing agent comprising a polymer to the yarn, ribbon or sheet.

Fabricating a nanofiber sheet, ribbon, or yarn by a continuous process that includes synthesizing a nanofiber forest in a forest growth region on a substrate, wherein the nanofiber forest comprises a parallel array of nanofibers, and further includes drawing said nanofibers from the nanofiber forest to form a primary assembly that is a sheet, ribbon or yarn. The substrate continuously moves from the furnace growth region into a region where the nanofibers in the forest are drawn.

The present invention is directed to nanofiber yarns, ribbons, and sheets; to methods of making said yarns, ribbons, and sheets; and to applications of said yarns, ribbons, and sheets. In some embodiments, the nanotube yarns, ribbons, and sheets comprise carbon nanotubes. Particularly, such carbon nanotube yarns of the present invention provide unique properties and property combinations such as extreme toughness, resistance to failure at knots, high electrical and thermal conductivities, high absorption of energy that occurs reversibly, up to 13% strain-to-failure compared with the few percent strain-to-failure of other fibers with similar toughness, very high resistance to creep, retention of strength even when heated in air at 450&#xb0; C. for one hour, and very high radiation and UV resistance, even when irradiated in air. Furthermore these nanotube yarns can be spun as one micron diameter yarns and plied at will to make two-fold, four-fold, and higher fold yarns. Additional embodiments provide for the spinning of nanofiber sheets having arbitrarily large widths. In still additional embodiments, the present invention is directed to applications and devices that utilize and/or comprise the nanofiber yarns, ribbons, and sheets of the present invention.

A nanofiber forest on a substrate can be patterned to produce a patterned assembly of nanofibers that can be drawn to form nanofiber sheets, ribbons, or yarns.

A process of producing a yarn, ribbon or sheet comprising nanofibers that includes infiltrating a liquid into the yarn, ribbon or sheet and evaporating the liquid from the yarn, ribbon, or sheet to strengthen the yarn, ribbon or sheet. The yarn, ribbon, or sheet can be formed by solid-state draw from a carbon nanotube forest.

A suspended nanotube film (or films) producing sound by means of the thermoacoustic (TA) effect is encapsulated between two plates, at least one of which vibrates, to enhance sound generation efficiency and protect the film. To avoid the oxidation of carbon nanotubes at elevated temperatures and reduce the thermal inertia of surrounding medium the enclosure is filled with inert gas (preferably with high heat capacity ratio, &#x3b3;=C/C, and low heat capacity, C). To generate sound directly as the first harmonic of applied audio signal without use of an energy consuming dc biasing, an audio signal modulated carrier frequency at much higher frequency is used to provide power input. Various other inventive means are described to provide enhanced projected sound intensity, increased projector efficiency, and lengthened projector life, like the use of infrared reflecting coatings and particles on the projector plates, non-parallel sheet alignment in sheet stacks, and cooling means on one projector side.

Encapsulated thermoacoustic projector based on freestanding carbon nanotube film

A device including an array of aligned conductive channels. The conductive channels are operable for directional transport of species selected from the group consisting of electrons, ions, phonons, and combinations thereof. The conductive channels are provided for by nanofibers in a form selected from the group consisting of ribbons, sheets, yarns, and combinations thereof.

Fabricating a nanofiber ribbon or sheet with a process that includes providing a primary assembly by arranging carbon nanotube nanofibers in aligned arrays, the arrays having a degree of inter-fiber connectivity, drawing the carbon nanotube nanofibers from the primary assembly into a sheet or ribbon, and depositing the sheet or ribbon on a substrate.

Fabrication of nanofiber ribbons and sheets

Nanofiber ribbons and sheets and fabrication and application thereof

Nanofiber actuators and strain amplifiers having a material that generates a force or generates a displacement when directly or indirectly electrically driven. This material is an aerogel or a related low density or high density network comprising conducting fibers that are electrically interconnected and can substantially actuate without the required presence of either a liquid or solid electrolyte. Reversible or permanently frozen actuation is used to modify the properties of the actuator material for applications.

Growing community of inventors

Dallas, TX, United States of America

Ali E Aliev