U.S. patent application number 14/776401 was filed with the patent office on 2016-02-04 for methods of making nanofiber yarns and threads.
This patent application is currently assigned to COOPER CORE TECHNOLOGIES, INC.. The applicant listed for this patent is COOPER CORE TECHNOLOGIES, INC.. Invention is credited to William Cooper.
Application Number | 20160032499 14/776401 |
Document ID | / |
Family ID | 50391551 |
Filed Date | 2016-02-04 |
United States Patent
Application |
20160032499 |
Kind Code |
A1 |
Cooper; William |
February 4, 2016 |
METHODS OF MAKING NANOFIBER YARNS AND THREADS
Abstract
There is disclosed a method of making a material comprising an
assembly of at least one spun yarn, comprising: synthetic inorganic
fibers, such as carbon, metal, oxides, carbides or alloys or
combinations thereof, wherein a majority of the fibers: (a) are
longer than 300 (b) have a diameter ranging from 0.25 nm and 700
nm, and (c) are substantially crystalline, wherein the yarn has
substantial flexibility and uniformity in diameter. In one
embodiment, the method comprises spinning yarn by pulling fibers
from a bulk material with at least one spinner that has real time
feedback controls.
Inventors: |
Cooper; William; (Santa Fe,
NM) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
COOPER CORE TECHNOLOGIES, INC. |
Albuquerque |
NM |
US |
|
|
Assignee: |
COOPER CORE TECHNOLOGIES,
INC.
Albuquerque
NM
|
Family ID: |
50391551 |
Appl. No.: |
14/776401 |
Filed: |
March 14, 2014 |
PCT Filed: |
March 14, 2014 |
PCT NO: |
PCT/US14/27405 |
371 Date: |
September 14, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61785183 |
Mar 14, 2013 |
|
|
|
Current U.S.
Class: |
57/59 ; 264/103;
264/105; 264/129; 264/176.1; 264/40.7; 264/406; 264/448 |
Current CPC
Class: |
Y10S 977/742 20130101;
Y10S 977/847 20130101; B82Y 30/00 20130101; Y10S 977/961 20130101;
D06M 15/70 20130101; Y10S 977/753 20130101; D02G 3/02 20130101;
D10B 2101/122 20130101; D01D 5/06 20130101; C01B 32/18 20170801;
D02G 3/36 20130101; D06M 2200/40 20130101; D02G 3/16 20130101; B82Y
40/00 20130101 |
International
Class: |
D02G 3/16 20060101
D02G003/16; D01D 5/06 20060101 D01D005/06; C01B 31/02 20060101
C01B031/02 |
Claims
1. A method for the fabrication of material comprising an assembly
of at least one spun yarn, said method comprising forming a yarn by
spinning synthetic inorganic fibers from a bulk material, wherein
said spinning is under feedback control based on a feedback signal,
wherein said spindle containing the nano-fibers is spinning
relative to a take-up spindle at a relative angular velocity
ranging from 30 rpm to 500,000 rpm, wherein the said angular
velocity is in the axial direction of the as spun yarn, wherein the
said nano-fibers are substantially aligned prior to spinning,
wherein a majority of said fibers: (a) are longer than 300 .mu.m,
(b) have a diameter ranging from 0.25 nm and 700 nm, and (c) are
substantially crystalline, to produce a yarn that has substantial
flexibility and uniformity in diameter.
2. The method of claim 1, further comprising attaching at least one
molecular component to the synthetic inorganic fibers chosen from
but not limited to metallic clusters, nano-fibers, carbon
nanotubes, metallic coatings, organic functional groups, proteins,
peptides, graphene, DNA, polymers and any combination thereof.
3. The method of claim 1, wherein said adding is accomplished by
exposing the fibers to physical vapor deposition, chemical vapor
deposition, solution phase adsorption, supercritical CO.sub.2,
plasma deposition, ion implantation, or any combination
thereof.
4. The method of claim 1, wherein the said uniformity in diameter
is accomplished through feedback control of the spinning parameters
comprising but not limited to spindle speed, yarn take-up speed,
applied capacitive forces, applied magnetic forces, atmospheric
conditions, concentration of spinning agent, sliver thickness,
sliver alignment, sliver density, spindle fiber federate, roving,
dispersion, carding, or any combination thereof, wherein a feedback
signal is comprised of automated measurements comprising but not
limited to conductivity, resistance, capacitance, inductance,
optical, tension, vibrational frequencies, gamma-ray backscatter,
x-ray backscatter or any combination thereof.
5. The method of claim 1, wherein the additives are applied to the
fiber with feedback control of the application parameters
comprising but not limited to voltage, temperature, pressure,
concentration, composition, frequency, current, or any combination
thereof, wherein a feedback signal is comprised of automated
measurements comprising but not limited to chemical affinity,
conductivity, resistance, capacitance, inductance, optical,
tension, vibrational frequencies, gamma-ray backscatter, x-ray
backscatter or any combination thereof.
6. The method of claim 1, further comprising cabling at least one
said yarn with at least another said yarn, wherein the said cabling
is accomplished with spooling and spin tightening the said at least
one yarn, contacting the said spun tightened yarn with a tension
controller, contacting the said spun tightened yarn with another
spun tightened yarn, and take-up of the said cabled multiply
yarn.
7. The method of claim 1, further comprising applying at least one
sizing agent to said yarn, wherein said sizing agents is chosen
from poly-aromatic-hydrocarbons, nanoscale graphene structures,
starches, polyvinyl alcohols carboxymethylcellulose, acrylates,
waxes, dioctyl phthalate, surfactants, alcohols, oils or any
combination thereof.
8. The method of claim 1, wherein said fiber is comprised of
carbon, metal, oxides, carbides or alloys or combinations
thereof.
9. The method of claim 1, wherein said yarn is comprised of more
than one species of fibers that are substantially hollow,
substantially solid, filled with a secondary material, or any
combination thereof.
10. The method of claim 1, wherein said fiber is chosen from
meta-materials, magnetic materials, semi-conducting materials,
conductive materials, doped materials, super-conductive materials,
adsorptive materials, insulation materials, or any combination
thereof.
11. The method of claim 1, further comprising infiltrating said
yarn with a polymer.
12. The method of claim 1, wherein the material comprises a thread,
rope, woven two dimensional fabric, woven three dimensional
article, a three dimensional printed article or any combination
thereof.
13. The method of claim 1, wherein the yarn comprises a long axis,
and the fibers within the spun yarn are substantially aligned and
twisted about said long axis.
14. The method of claim 1, further comprising twisting together two
or more spun yarns to form a twisted pair.
15. The method of claim 14, wherein said twisted pair is twisted
while under a tension resulting in a pressure between the twisted
pair ranging from 1 mPa and 30 TPa.
16. The method of claim 15, wherein said tension is translated into
an internal pressure with force vectors pointed inward to the
global axis of the twisted pair to enhance the integrity of the
said twisted pair.
17. The method of claim 14, wherein the said twisted pair is
twisted together with at least one other said twisted pair to form
a cable.
18. The method of claim 17, wherein the cable has a strength of
ranging from 10 kPa to 300 GPa.
19. The method of claim 1, wherein said yarn is sufficiently
conductive at frequency between 1.times.10.sup.-6 Hz and
3.times.10.sup.19 Hz.
20. The method of claim 1, wherein the yarn has a diameter between
10 nm and 5 mm.
Description
[0001] This application claims the benefit of domestic priority to
U.S. Provisional Patent Application No. 61/785,183, filed Mar. 14,
2013, which is herein incorporated by reference in its
entirety.
[0002] The present disclosure relates to methods of making a
material comprised of small diameter inorganic fibers spun into
yarns, threads cables and ropes. Materials made by such methods as
well as composites are also disclosed.
[0003] Metals and plastics and natural materials have long been
favorites for many technical applications because of their
versatile physical and chemical properties including malleability,
strength, durability, and/or corrosion resistance. However, for an
increasing number of applications, ultra-light materials exhibiting
comparable or higher strength, durability and /or conductivity are
needed. To date, the need for these materials has been primarily
limited to high-tech applications, such as high performance
aerospace and high-end electronics. However, they are becoming
increasingly needed in other areas as well, such as ballistic
mitigation applications (e.g. micro-meteorite protection for
satellites and space vehicles), and a wide range of commercial
applications involving heat sinks, air conditioning units,
computers, casings, and vehicle bodies, unmanned aerial vehicles,
lightweight energy efficient telecommunications equipment,
robotics, and high end filtration, purification, separation
devices, to name a few.
[0004] Recent advances in materials science and nanotechnology have
led to the creation of a new class of micro and nano scale fibers
with conductivity, optical mechanical, surface area, and quantum
properties never seen before. Silicon Nano-fibers, Diamond fibers,
colossal carbon tubes, multiwall gas phase carbon nanotubes,
multiwall arrayed carbon nanotube, single walled carbon nanotubes
and their unique properties have been known for some time. Examples
of literature disclosing an inorganic nano-fiber, carbon nanotubes
including, J. Catalysis, 37, 101 (1975); Journal of Crystal Growth
32, 35 (1976); "Formation of Filamentous Carbon`, Chemistry of
Physics of Carbon, ed. Philip L. Waker, Jr. and Peter Thrower, Vol.
14, Marcel Dekker, Inc., New York and Base 1, 1978; and U.S. Pat.
No. 4,663,230, issued Dec. 6, 1984. Also included by reference
"Novel Two-Step Method for Synthesis of High-Density
Nanocrystalline Diamond Fibers" Chem. Matter., 2008, 20(5), pp
1725-1732.
[0005] However, recent interest in carbon filamentary material was
stimulated by a paper by lijima (1991) which made producing these
inorganic materials possible. These early studies and the work that
has developed from them has resulted in the discovery of a class of
nano-fiber material with remarkable mechanical, electrical and
thermal properties that can be produced on the industrial
scale.
[0006] Nano-fiber spinning has been accomplished through solution
phase chemistry (acid, sol-gel etc.), nano-fiber spinning of random
orientation from a CVD furnace, and dry spinning of a stationary
nano-fiber forest array. Included by reference: "Continuous carbon
nanotube composite fibers: properties, potential applications, and
problems" J. Mater. Chem., 2004, 14, 1-3.
[0007] The bulk of the commercial effort for producing nano-fiber
yarns use solution based chemistry that requires relatively short
nano-fibers (<100 um). In addition these nano-fibers were grown
from a random catalyst support or from a gas phase fluidized bed.
These synthetic methods not only produce relatively short
nano-fibers, they produce fibers that have significant curvature
due to lattes dislocations within the nano-fiber structure.
[0008] All of the nano-fiber nanotube yarns produced to date using
the techniques discussed above, have limitations. Solution based
methods have not yet been made to work with nano-fibers longer than
approximately 100 .mu.m most likely due to uncontrolled
entanglement.
[0009] Nano-fiber spinning and production of yarns directly from
the synthesis chemical vapor deposition furnace has significant
limitations. The nano-fibers are themselves randomly oriented, have
significant curvature, and contain significant quantities of
metallic catalyst adsorbed and imbedded in the nano-fibers.
Furthermore the cost of the material is significant thus making
real commercialization unlikely. Included by reference: "Continuous
Multilayered Carbon Nanotube Yarns" in Advanced Materials Vol. 22,
Issue 6, 692-696, Feb. 9, 2010.
[0010] Thus far the best yarns that can be made are from long
nano-fibers 500 um or longer and are dry spun from a forest.
Significant efforts have been undertaken to produce scalable and
commercial methods for dry spinning of spun yarns from
multi-millimeter multi-walled carbon nanotube forests. It is well
known and accepted by the nano-fiber yarn and composites community,
that this method has the potential to make yarns with bulk strength
in the 60 GPa range. Others have published results of dry spinning
with short (235 um tall) forests yielding further evidence as to
the challenge of spinning yarn from long nano-fiber forests.
Included by reference: "Carbon nanotube yarns with high tensile
strength made by a twisting and shrinking method" Nanotechnology 21
(2010) 045708.
[0011] Yet, others must use polymers to direct spin nano-fibers
into a stable and strong nano-fiber yarn. Included by reference:
"Manufacturing polymer/carbon nanotube composite using a novel
direct process" Nanotechnology, Vol. 22, No. 14, 2011.
[0012] The principle reason for the near impossibility of direct
spinning of a ultra-long nano-fiber forest is the fact nano-fibers
in this form are very inconsistent. It has been speculated that
spinning will never produce quantities of quality yarns due to the
fact that all forest type nano-fibers have significant
inconsistencies internal to the forest structure. Zhu reports the
routine spinning of yarns 10 cm long in "Carbon-Nanotube Cotton for
Large-Scale Fibers" in Advanced Materials Vol. 19, Issue 18,
2567-2570 September, 2007.
[0013] Furthermore many authors including the present one have
taught functionalization and bonding between nano-fibers, including
U.S. Patent Application No. 2009/0282802 A1, which is herein
incorporated by reference in its entirety. Bonding between short
fibers in a spun yarn will be weaker less conductive yarn than a
substantially uniform yarn made from substantially longer
nano-fiber containing chemical bonding. The present disclosure
teaches one skilled in the art methods for making continues quality
spun yarns from ultra-long nano-fibers, and articles made
therefrom.
SUMMARY OF THE INVENTION
[0014] The present disclosure teaches a novel method for direct
spinning of ultra-long nano-fiber forest by using feedback control
in the spinning process. Thus, through feedback control tens of
kilometers of high quality nano-fiber yarn have been produced
without the use of polymers, or spinning agents.
[0015] In one embodiment, there is disclosed a method of making a
material comprising an assembly of at least one spun yarn,
comprising: synthetic inorganic fibers, such as carbon, metal,
oxides, carbides or alloys or combinations thereof, wherein a
majority of the fibers: (a) are longer than 300 .mu.m, (b) have a
diameter ranging from 0.25 nm and 700 nm, and (c) are substantially
crystalline, wherein the yarn has substantial flexibility and
uniformity in diameter.
[0016] In one embodiment, the method comprises spinning yarn by
pulling fibers from a bulk material with at least one spinner that
has real time feedback controls.
[0017] The accompanying Figures, which are incorporated in and
constitute a part of this specification, illustrate several
exemplary embodiments of the disclosure and, together with the
description, serve to explain the principles of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1. SEM image of the raw carbon nanotube material
as-received from Nanotech Labs.
[0019] FIG. 2. Schematic drawings showing generic methods for
producing carbon nanotube yarn directly from aligned carbon
nanotube forest. FIG. 2(a) shows a carbon nanotube forest being
spun while the yarn is drawn. FIG. 2(b) shows how the aligned
carbon nanotube forest is kept stationary while the yarn is being
drawn and twisted.
[0020] FIG. 3. Are SEM images showing various inventive embodiments
made according the present invention. In particular, FIG. 3(a)
shows a single ply (left), a double-ply (middle), quadruple-ply
(right) thread made according the present invention. FIG. 3(b)
shows a collection of single ply carbon nanotube thread containing
chemically linked carbon nanotubes made according to the present
invention.
[0021] FIG. 4. A schematic drawing of the production of an aligned
carbon nanotube thin film by rolling. Left: A piece of carbon
nanotube forest impregnated with polyethylene glycol (PEG) is
sandwiched between two layers of paper; middle: Rolling is used to
press the carbon nanotube forest into a thin carbon nanotube film;
Right: The resulting carbon nanotube thin film is sandwiched
between two layers of paper. The paper was made from a mixture of
glass fibers and bi-component polymer fibers.
[0022] FIG. 5. SEM images of a carbon nanotube thin film. Left: low
magnification (50.times.). Right: high magnification
(3000.times.).
[0023] FIG. 6. A schematic showing carbon nanotube threads being
produced from aligned carbon nanotube ribbons.
[0024] FIG. 7. SEM images of two spools of carbon nanotube threads
made from aligned carbon nanotube ribbons. Left: single ply thread,
Right: a double ply thread.
[0025] FIG. 8. Two SEM images of a braided carbon nanotube
material.
[0026] FIG. 9. A schematic drawing of a piece of carbon nanotube
fabric.
[0027] FIG. 10. SEM images of carbon nanotube-based fabric made
from one ply threads (left) and two ply threads (right).
[0028] FIG. 11. Chemical reactions involved in the carbon nanotube
cross-linking through functionalization with
vinyl-triethoxysilane.
[0029] FIG. 12. Chemical reactions involved in the carbon nanotube
cross-linking through functionalization with
vinyl-triethoxyaminosilane.
[0030] FIG. 13. Chemical reactions involved in the carbon nanotube
functionalization with carboxyl groups followed by cross-linking
with a diamine.
[0031] FIG. 14. Chemical reactions involved in the carbon nanotube
carboxylation followed by thermal cross-linking.
[0032] FIG. 15. Stress-strain curves for carbon nanotube strips
showing the relative mechanical behavior of the three types of
media.
[0033] FIG. 16. Single ply yarn spinning machine with spindle and
take up reel.
[0034] FIG. 17. Close up of spindle loaded with forest of carbon
nanotubes and take-up spool.
[0035] FIG. 18. View of yarn spinning feedback controller panel
with feedback control signal in the upper left-hand corner using
LabView.TM.
[0036] FIG. 19. Same as FIG. 18 approximately 10 sec later in time,
thus demonstrating the real-time control over the spindle speed and
the take up speed as a function of thread conductivity.
[0037] FIG. 20. View of spindle turning at about 7,000 RPM to
produce an approximately 22 um diameter spun yarn with about a 30
degree twist angle with respect to the yarn axis, produced at a
speed of about 5 ft/min. The as spun yarn is rastered onto the take
up spool to substantially reduce uncontrolled wrap to wrap yarn
entanglement on the spool.
[0038] FIG. 21. Same view as FIG. 20 except the process is at a
standstill to show the slip ring to spindle shaft. The forest
holder is conductive thus transmitting feedback signal through the
forest to the thread. Note the thread must pass through a channeled
electrically grounded conductive block. The gap between the spindle
head and the grounded channel is approximately 1 cm. As the
thickness of the thread changes due to inconsistencies within the
carbon nanotube forest the feedback signal will tell the controller
to change spindle speed and take-up speed such that the thread will
become thinner or thicker. Thus the controller will cause
inconsistency in the forest to be mitigated.
[0039] FIG. 22. is a view of the feedback control program written
in LabView.TM. by National Instruments.TM..
[0040] FIG. 23. is a view of the thread signal amplification
electronics and power transistor for motor control. This
"electronics layer" sits between a National Instruments.TM. data
acquisition unit and the mechanical layer. The red buttons are
system start and stop. The switches are forced motor run that aide
in initial system threading.
[0041] FIG. 24. Three spools of single ply carbon nanotube
yarn.
[0042] FIG. 25. One spool containing two samples a) a 45 ply cable
of carbon nanotube yarns b) a 135 ply cable of carbon nanotube
yarns.
[0043] FIG. 26. This is a three to one nano-fiber yarn cabling
machine with tension feedback control. The system uses a total 8
encoded motors with gear reduction.
[0044] FIG. 27. This is the driven cable take-up. The small motor
spools the cabled yarn while another larger motor, mounted to the
aluminum frame twists the ply's into one cable. A multi-conductor
commercial slip ring was used to power and control the micro-motor
mounted to the spinning shaft. At the lower left-hand corner of
this image is a three dimensional yarn to cable guide made from a
copper graphite composite.
[0045] FIG. 28. Shows the spool out assembly mounted in a Plexiglas
pedestal. The spool out device can be seen as a set of gears to
both spool and twist the yarn. Also present in this Figure are the
three feedback tension devices. Each device has an optical path
through the center of the armature joint. An LED in mounted on one
side and a sensor on the other. Between the LED and the sensor is a
set of polarized filters. One filter is mount stationary in the
optical path, the other is mounted to the armature. As the armature
moves the amount of light the sensor receives changes. In this way
the controller will spool out yarn on an as needed basis. The each
tension arm also delivers a substantially uniform tension to each
of the three yarns. The same system can be used to cable three
multiply thread into a cable. Furthermore same system can be used
to cable three cables into a larger cable. Each tension arm can be
mounted with an upper limit of approximately 3 kg to deliver
substantial pressure between the cabled elements.
[0046] FIG. 29. is the cabling controller dash board. From this
dash board cabling parameters can be controlled.
[0047] FIG. 30. is the controller program in National Instruments
LabView visual programming language for the cabling machine.
[0048] FIG. 31. is the electronics layer for the cabling machine.
Every motor requires a power transistor to amplify the control
signal coming back from the computer to power the motors as can be
seen on the upper left-hand side of this Figure. Furthermore
capacitors were used to substantially reduce noise from the motors
so as to not adversely affect the circuit.
DEFINITIONS
[0049] The term "substantially crystalline" refers to a fiber where
the materials comprising the fiber contain a repeating unit cell
such that there exists substantially global symmetry around the
major axis. The major axis could exist in free space such as a
major axis of a fiber in a spiral configuration. Geometric shapes
of fibers: tubes, cylinders, ribbons, spiraled tubes, cylinders,
ribbons. A counter example would be a carbon nanotube with random
defects in the crystalline structure causing random curvature, and
random shape. Such a "fiber" does not meet the requirement for
substantial symmetry along at least one axis. The utilization of
resonate spectroscopy of a nano-scale structure will have
substantial resonate peeks if substantial symmetry along at least
one axis exists.
[0050] The term "carbon nanotubes" or "CNTs" are defined herein as
crystalline structures comprised of one or many closed concentric,
locally cylindrical, graphene layers. Their structure and many of
their properties are described in detail in Carbon Nanotubes:
Synthesis, Structure, Properties, and Applications, Topics in
Applied Physics. (Vol. 80. 2000, Springer-Verlag, M. S.
Dresselhaus, G. Dresselhaus, and P. Avouris, eds.) which is herein
incorporated by reference. Carbon nanotubes have demonstrated very
high mechanical strengths and stiffness (Collins and Avouris, 2000,
"Nanotubes for Electronics". Scientific American: 67, 68, and 69.)
They also have very high electrical conductivity which allow
current densities of more than 1,000 times that in metals (such as
silver and copper). These properties, including the high specific
strength and stiffness, will be beneficial to the materials
disclosed herein.
[0051] The term "yarn" is defined as a bundle of filaments
approximately spirally arranged to form a very-high aspect ratio,
approximately cylindrical structure. The filaments within the yarn
are substantially parallel, in a local sense, to neighboring
filaments.
[0052] The phrase "carbon nanotube yarn" is a yarn composed of a
plurality of carbon nanotubes.
[0053] The terms "thread" and "rope" are defined as high aspect
ratio, approximately cylindrical structures composed of more than
one strand of yarn. The term "rope" is defined as a high aspect
ratio approximately cylindrical structure composed of one yarn or
thread surrounded by additional carbon nanotubes forming the mantle
or outer sheath.
[0054] The phrase "substantial flexibility" (or variations thereof)
in the article (e.g., fiber, thread, rope, yarn) means that the
article does not experience significant, if any work hardening. An
example of a natural (i.e., prior art) material that has
substantial flexibility is silk.
[0055] The phrase "substantially uniformity in number of
nano-fibers" means that when various cross sections of a length
material comprising the nano-fibers is analyzed, there are
substantially the same number of nano-fibers along the entirety of
the length, such as within 10% or even 5%.
[0056] Other than the techniques mentioned above, post treatment of
the disclosed materials could be achieved via high temperature
thermal annealing, passing high electric current through the
disclosed materials, electron beam and/or ion radiation (chemical
reactions involved in these process are shown in FIG. 14). Further
improvement of the thermal annealing method could be attempted by
introducing additional source of carbon into the thread prior the
annealing.
[0057] Two of the above mentioned cross-linking approaches were
employed in Example 5 and mechanical testing results from three
types of materials are shown in FIG. 15. Clearly, mechanical
performance of the materials could be enhanced as expected by the
used chemical-linking approaches between carbon nanotubes.
[0058] In one embodiment, there is disclosed a material comprising
an assembly of at least one spun yarn, comprising: synthetic
inorganic fibers, such as carbon, metal, oxides, carbides or alloys
or combinations thereof wherein a majority of the fibers: (a) are
longer than 300 .mu.m, (b) have a diameter ranging from 0.25 nm and
700 nm, and (c) are substantially crystalline, wherein the yarn has
substantial flexibility and uniformity in size and shape, such as
in diameter.
[0059] In one embodiment, the yarn further comprises a sizing
agents chosen from poly-aromatic-hydrocarbons, nanoscale graphene
structures, starches, polyvinyl alcohols carboxymethylcellulose,
acrylates, waxes, dioctyl phthalate, surfactants, alcohols, oils or
any combination thereof.
[0060] In one embodiment, the yarn used according to the present
disclosure may be comprised of more than one species of fibers. In
addition or alternatively, the yarn may be infiltrated with a
polymer.
[0061] In another embodiment, the yarn further comprises molecular
components chosen from metallic clusters, metallic coatings,
organic functional groups, proteins, peptides, graphene, DNA,
polymers and any combination thereof.
[0062] It is to be appreciated that the fiber disclosed herein may
be substantially hollow, substantially solid, filled with a
secondary material, or any combination thereof.
[0063] The fiber may be chosen from a variety of materials, such as
meta-materials, magnetic materials, semi-conducting materials,
conductive materials, doped materials, super-conductive materials,
adsorptive materials, insulation materials, or any combination
thereof.
[0064] The disclosed fibers may comprise carbon-based material,
such as graphene or exfoliated graphite. In one embodiment, the
exfoliated graphite is in the form of nano-platelets, which are
less than 50 nanometers thick, such as between 1 and 25 nanometers
thick, or even within a range of 1 to 15 nanometers thick, with
diameters ranging from sub-micrometer to 100 micrometers. The
platelet shape associated with these exfoliated graphite
embodiments, provide multiple edges that enable them to be readily
modified chemically for enhanced end-use properties, or for
improved processing properties such as improved dispersion in
polymers.
[0065] In various embodiments, the material comprises a thread,
rope, woven two dimensional fabric, woven three dimensional
article, a three dimensional printed article or any combination
thereof. For example, the yarn comprises a long axis, and the
fibers within the spun yarn may be substantially aligned and
twisted about said long axis. The yarn may have a diameter ranging
from 10 nm to 5 mm and be sufficiently conductive at frequency
ranges from 1.times.10.sup.-6 Hz to 3.times.10.sup.19 Hz.
[0066] In one embodiment, the material comprises two or more spun
yarns twisted together to form a twisted pair. In another
embodiment, the twisted pair is twisted while under a tension
resulting in a pressure between the twisted pair ranging from 1 mPa
and 30 TPa. The inventors have discovered that when tension is
translated into an internal pressure with force vectors pointed
inward to the global axis of the twisted pair the integrity of the
twisted pair can be enhanced.
[0067] In another embodiment, the twisted pair may be twisted
together with at least one other twisted pair to form a cable to
form a cable has a strength of ranging from 10 kPa to 300 GPa.
[0068] In one embodiment, there is disclosed a method for the
fabrication of material comprising an assembly of at least one spun
yarn, the method comprising forming a yarn by spinning synthetic
inorganic fibers from a bulk material wherein the said spinning is
under feedback control based on a feedback signal, wherein the said
spindle containing the nano-fibers is spinning relative to a
take-up spindle at a relative angular velocity of between 30 rpm
and 500,000 rpm, wherein the said angular velocity is in the axial
direction of the as spun yarn, wherein the said nano-fibers are
substantially aligned prior to spinning, wherein a majority of the
fibers: (a) are longer than 300 .mu.m, (b) have a diameter ranging
from 0.25 nm and 700 nm, and (c) are substantially crystalline, to
produce a yarn that has substantial flexibility and uniformity in
diameter.
[0069] In one embodiment, uniformity in diameter is accomplished
through feedback control of the spinning parameters comprising but
not limited to spindle speed, yarn take-up speed, applied
capacitive forces, applied magnetic forces, atmospheric conditions,
concentration of spinning agent, sliver thickness, sliver
alignment, sliver density, spindle fiber federate, roving,
dispersion, carding, or any combination thereof, wherein a feedback
signal is comprised of automated measurements comprising but not
limited to conductivity, resistance, capacitance, inductance,
optical, tension, vibrational frequencies, gamma-ray backscatter,
x-ray backscatter or any combination thereof.
[0070] In one embodiment, the method may further comprise adding
(or attaching) at least one molecular component to the synthetic
inorganic fibers chosen from but not limited to metallic clusters,
nano-fibers, carbon nanotubes, metallic coatings, organic
functional groups, proteins, peptides, graphene, DNA, polymers and
any combination thereof.
[0071] In one embodiment, the method of adding at least one
molecular component is accomplished by exposing the fibers to
physical vapor deposition, chemical vapor deposition, solution
phase adsorption, supercritical CO.sub.2, plasma deposition, ion
implantation, or any combination thereof.
[0072] In one embodiment, the additives are applied to the fiber
with feedback control of the application parameters comprising but
not limited to voltage, temperature, pressure, concentration,
composition, frequency, current, or any combination thereof,
wherein a feedback signal is comprised of automated measurements
comprising but not limited to chemical affinity, conductivity,
resistance, capacitance, inductance, optical, tension, vibrational
frequencies, gamma-ray backscatter, x-ray backscatter or any
combination thereof.
[0073] In one embodiment, yarns threads or cables are further
cabled together. The cabling is accomplished with spooling and spin
tightening the said at least one yarn, contacting the said spun
tightened yarn with a tension controller, contacting the said spun
tightened yarn with another spun tightened yarn, and take-up of the
said cabled multiply yarn.
[0074] The above mentioned yarns, threads or ropes made with carbon
nanotubes having differing characteristics can be woven together to
create unique materials that take advantage of the incredibly
diverse properties of the carbon nanotube. For example, depending
on the application, carbon nanotubes that exhibit unique
electrical, thermal, electromagnetic, strength, and
filtration/detection properties can be combined in a yarn to be
woven into a multifunctional material.
[0075] The invention will be further clarified by the following
non-limiting examples, which is intended to be purely exemplary of
the invention.
EXAMPLES
Example 1
Carbon Nanotube Yarn and Thread From Dry Process
[0076] Raw carbon nanotubes were provided by NanoTech Labs
(Yadkinville, N.C. 27055) in clusters typically measuring 3 to 5 mm
thickness, 1-2 cm long and 1-2 cm wide. They were used for carbon
nanotube yarns making with individual carbon nanotube measuring 3-5
mm in length. Yarns according to this example were made by: a)
continuously and sequentially pulling carbon nanotubes from the
as-received carbon nanotube clusters; b) twisting the carbon
nanotube fibers to make the yarn; c) winding the resulting yarn on
to the collecting spool; d) carboxyl functionalization of the spool
of yarn; e) heat treating at 500.degree. C. for 30 min to achieve
cross-linking within the yarn. The twisting and collection was
performed automatically to achieve uniformity.
[0077] The yarns shown in FIG. 3 were made by using the first
method (shown in FIG. 2), which comprised spinning the carbon
nanotube forest while the yarn was drawn. By using counter-spinning
technique, the yarn (also called singly ply thread) could be spun
into multiple-ply thread. SEM images of single, double and
quadruple-ply threads are shown in FIG. 3. These threads were made
from high quality carbon nanotubes and the individual carbon
nanotube measures 3 to 5 mm in length. The yarn and thread shown in
this disclosure incorporating the three new features: long carbon
nanotubes, twisted and chemically linked together.
Example 2
Wet Spun Carbon Nanotube Yarns
[0078] The carbon nanotube yarns according to this example were
produced by: a) impregnating carbon nanotube material with
PEG-2000; b) removing the excess PEG from the carbon nanotube
material to make carbon nanotube dough; c) sandwiching the
resulting carbon nanotube dough between two layers of paper; d)
producing thin film by repeatedly running roller over the carbon
nanotube dough; e) slitting the carbon nanotube thin film into
narrow ribbons; f) twisting the narrow ribbons into yarns; g)
baking the resulting yarns at 220.degree. C. for half an hour; h)
carboxylation of the spool of yarn; i) heating at 500.degree. C.
for 30 mins to achieve cross-linking within the yarn.
[0079] The method for making carbon nanotube thin film is depicted
in FIG. 4 and the SEM images of the resulted thin film are shown in
FIG. 5. Low magnification SEM image of carbon nanotube ribbon shows
a total width of the ribbon of about 1.5 mm. High magnification SEM
image is showing carbon nanotubes alignment within the film.
[0080] The method for making carbon nanotube yarns from aligned
carbon nanotube ribbons is depicted in FIG. 7. SEM images of two
spools of carbon nanotube yarn and thread made from the above
aligned carbon nanotube ribbons are shown in FIG. 8. These yarn and
thread were made by twisting and pulling the aligned carbon
nanotube ribbons and both a single ply and a double ply carbon
nanotube yarn and thread were made from the thin film shown in FIG.
6.
Example 3
Braided Carbon Nanotube Materials
[0081] By using the techniques shown in example 1, some double ply
threads were made. Using the conventional technique, under optical
microscope, a piece of braided material was made by tweezers. Two
SEM images of a braided carbon nanotube material are shown in FIG.
8 and three strands of double spun carbon nanotube yarns were used
in this braided material.
Example 4
Carbon Nanotube Fabric
[0082] By using the techniques shown in example 1, some single ply
and double ply threads were made. A schematic drawing of a piece of
carbon nanotube fabric is shown in FIG. 9. Under optical
microscope, a homemade loom was used for the weaving of the fabric.
SEM images of the piece of woven fabric are shown in FIG. 10. The
fabric was woven from a mixture of single and double spun carbon
nanotube yarns. The diameter of the yarns is in the range of 20 to
50 um.
Example 5
Chemical-Linking of Carbon Nanotubes
[0083] The experiments on cross-linking of carbon nanotubes were
performed over carbon nanotube strips. The same process could be
applied to the disclosed materials in this invention.
[0084] Long CNTs (3-5 mm in length) with diameters of 30-50 nm
provided by NanoTechLabs.TM. were used as received. The detail
procedure of the experiments is described as:
[0085] I. Thermal Annealing [0086] (1) Long CNTs were acid washed
and dispersed. [0087] (2) Suspension of carbon nanotubes were
deposited onto carbon cloth substrate discs. [0088] (3) Carbon
nanotube membrane was peeled off the substrate, pressed with a hand
roller and dried. [0089] (4) Seven thin strips of roughly 0.25 mm
thickness were slit from the central part of each membrane. These
strips were called untreated. [0090] (5) Four of the seven strips
were annealed at 500.degree. C. for half an hour. These strips were
called heat treated.
[0091] II. Chemical Treatment [0092] (1) Vinyltrialkoxysilanes were
attached to the long carbon nanotube sidewall via free radical
reaction. [0093] (2) Functionalized carbon nanotubes from step 1
were dispersed. [0094] (3) Suspension of carbon nanotubes were
deposited onto carbon cloth substrate discs. [0095] (4) Carbon
nanotube membrane was peeled off the substrate, pressed with a hand
roller and dried. [0096] (5) Carbon nanotube membrane was thermal
processed at 120-150.degree. C. to form siloxane --Si--O--Si--
bridges between the outer shells of the adjacent nanotubes.
[0097] All 10 strips were tested with an MTS Insight Tensile Tester
under uniaxial tensile loading and the stress-strain curves for
each strip are shown in FIG. 15. The early mechanical behavior of
both types of cross-linked strips is very similar (nearly equal
slope) with the chemically linked strips being able to withstand
higher applied stresses. Both types of treated strips were shown to
consistently carry a higher tensile loading before breaking and
have a steeper stress-strain relationship, conclusively
demonstrating an improvement in the mechanical behavior in tensile
strength.
Example 6
A Feedback Control Conductive Nano-Fiber Yarn Production
Machine
[0098] A Single ply yarn spinning machine with spindle and take up
raster and full feedback control was built, and is shown in FIGS.
16-23. As can be seen in FIG. 16 a mechanical layer is suspended
over an electronics layer. This was done to minimize delay,
capacitance and inductance in the control and power wires.
[0099] A motor mount was machined out of Plexiglas.TM. was
fabricated to hold a 10,000 rpm motor. A conductive cylindrical
element made of a copper graphite materials was used on the spindle
for the contact of a slip ring. A miniature vice was fabricated to
hold the carbon nanotube forest. This is also referred to herein as
the forest holder. The forest was oriented to be approximately 90
degrees to the yarn feed direction. A conductive pedestal made of
the same copper graphite material was fabricated to sit on top of a
grounded aluminum cylinder as shown in FIG. 16. The miniature vice
was made of aluminum and is conductive, thus transmitting feedback
signal through the forest to the thread. Note the thread must pass
through a channeled electrically grounded conductive block. The gap
between the spindle head and the grounded channel is approximately
1 cm.
[0100] As the thickness of the thread changes due to
inconsistencies within the carbon nanotube forest, the feedback
signal will tell the controller to change spindle speed and take-up
speed such that the thread will thin or thicken. Thus the
controller will cause inconsistency in the forest to be
mitigated.
[0101] A take up motor was used to spool the as spun yarn onto a
miniature spool is also mounted to the mechanical layer. As seen is
FIG. 16, this take up motor is the upper motor to the right of the
spindle motor and mounted in an aluminum block. A motor and screw
shaft was used to shuttle the raster tool back and forth so as to
spool the thread on the spool with a consistent back and forth
lay.
[0102] Below the mechanical layer an electronic layer was built.
This consists of a wire wrap board with components mounted thereon.
This electronics layer was built to receive signals from the
National Instruments.TM. DAC shown in FIG. 16 to the right, and
convert them to motor voltages. The electronics layer also receives
the high impendence signal from the as spun yarn, (the segment
between the spindle and the grounded channel block), filters and
amplifies the signal to send to the National Instruments.TM. DAC.
The control signal is then converted to digital form and becomes
the DataStream input for the LabView.TM. software controller.
Please refer to FIG. 23 for a view of the electronics layer.
[0103] Furthermore, hardware buttons and switches were installed to
aid in the operation of the machine. Red buttons were installed for
system start and stop. Switches were installed for forced motor run
used for initial system threading. Other switches were installed
for motor reversal for z twist and s twist control.
[0104] The software control panel layer was engineered so the user
has control over the responsiveness of the motors to the control
signal through a gain control and a bios control slider to the
right hand side of FIG. 18. Furthermore the nominal yarn thickness
can be substantially controlled by the X-bar controller. Close up
of spindle loaded with forest of nano-fibers and take-up spool.
Please refer to FIGS. 18, 19, & 22 for a view of the software
layer.
Example 7
Carbon Nanotube Yarn Produced With Said Yarn Production Machine
[0105] A carbon nanotube yarn was produced with the yarn production
machine of example 6. Approximately 3 mm long carbon nanotubes in
as grown forest form from NanoTechLabs.TM. was fitted into the
forest holder.
[0106] Sharp tweezers were then used to start the yarn. The
operator forced the spindle to turn while drawing the first segment
of yarn. This yarn was guided through copper graphite channels,
through a copper graphite shuttle and wrapped. The operator watched
the feedback signal on the computer screen (FIG. 18) to see that
the thread was stable and consistent at yarn was drawn from the
spinning spindle.
[0107] The spindle and take up gain and bias were set to values
seen if FIG. 18. The thickness of yarn was also set at a relative
value of X-bar at 3.5 as can in FIG. 18.
[0108] The machine was started and almost immediately spun a
substantially pure carbon nanotube yarn. The feedback signal was
photographed and can be seen in FIGS. 18 and 19.
[0109] A substantially consistent carbon nanotube yarn was spun.
The spindle turned at a nominal speed of 7,000 RPM to produce an
approximately 22 .mu.m diameter spun yarn with a nominal 30 degree
twist angle with respect to the yarn axis. The yarn was produced at
a speed of nominally 5 ft/min. Note spindle speed and take-up
speeds are always changing and that is determined by the
conductivity of the thread segment between the spindle and the
grounded channel. The as spun yarn is rastered on to the take up
spool to substantially reduce uncontrolled wrap to wrap yarn
entanglement on the spool. As an example of carbon nanotube yarn
make in this way please see FIG. 24.
Example 8
Nano-Fiber Yarn to Thread, Thread to Cable Cabling Machine
[0110] This example describes a nano-fiber yarn to thread, thread
to cable cabling machine that was built and shown in FIG. 26. For
an excessively delicate material nano-fiber yarn to be properly and
substantially tensioned, spun and cabled a tension feedback control
is required. The system used a total 8 encoded motors with gear
reduction for spinning and spooling. As can be seen in FIG. 26,
three feedback tension devices were conceived designed built tested
and used to substantially and precisely control tension on each
yarn, line during cabling.
[0111] A driven cable take-up was designed and built as can be seen
in FIG. 27. The small motor spools the cabled yarn while another
larger motor, mounted to the aluminum frame twists the ply's into
one cable. A multi-conductor commercial slip ring was used to power
and control the micro-motor mounted to the spinning shaft. At the
lower left-hand corner of this image is a three dimensional yarn to
cable guide made from a copper graphite composite.
[0112] Spool out device were conceived designed and fabricated to
both spool and twist the yarn. A gears train was built to deliver a
multi axis rotation to the microspools shown in FIG. 28. The spool
out assembly was mounted in a Plexiglas pedestal.
[0113] Furthermore the three feedback tension devices was built to
have an optical path through the center of the armature joint. An
LED in mounted on one side and a sensor on the other. Between the
LED and the sensor is a set of polarized filters. One filter is
mount stationary in the optical path, the other is mounted to the
armature. As the armature moves the amount of light the sensor
receives changes. In this way the controller will spool out yarn on
an as needed basis. The each tension arm also delivers a
substantially uniform tension to each of the three yarns. The same
system was used to cable three multiple threads into a cable.
Furthermore, the same system was used to cable three cables into a
larger cable. Each tension arm can be mounted with un upper limit
of approximately 3 kg to deliver substantial pressure between the
cabled elements.
[0114] An electronics layer was designed and built to sit between
the National Instruments data acquisition device and the mechanical
layer as can be seen in FIG. 31. Every motor required a power
transistor to amplify the control signal coming back from the
computer to power the motors as can be seen on the upper left-hand
side of this Figure. Furthermore capacitors were used to
substantially reduce noise from the motors so as to not adversely
affect the circuit.
[0115] The controller program was conceived, programmed and a dash
board layout was built as can be seen in FIG. 29. From this dash
board cabling parameters can be controlled. Furthermore the
controller program in National Instruments LabView visual
programming language for the cabling machine is presented in FIG.
30.
Example 9
Cable Comprising 135 Ply
[0116] A carbon nanotube cable of cables was fabricated using the
cabling machine of example 8. The process was started with 9 spools
five ply thread each approximately 20 ft long. The five ply cables
turned into 3 spools of 45 ply cable approximately 15 ft long.
There was fiber loss at the ends of the spools and some was saved
for imaging and analysis. The three spools of 45 ply cable were
turned into one spool of 135 ply cable approximately 10 ft long.
Please see FIG. 25 for an SEM of both the 45 ply cable and the 135
ply cable.
[0117] As used herein, the terms "a", "an", and "the" are intended
to encompass the plural as well as the singular. In other words,
for ease of reference only, the terms "a" or "an" or "the" may be
used herein, such as "a support", "an assembly", "the fiber", etc.,
but are intended, unless explicitly indicated to the contrary, to
mean "at least one," such as "at least one support", "at least one
assembly", "the at least one fiber", etc. This is true even if the
term "at least one" is used in one instance, and "a" or "an" or
"the" is used in another instance, e.g. in the same paragraph or
section. Furthermore, as used herein, the phrase "at least one"
means one or more, and thus includes individual components as well
as mixtures/combinations.
[0118] The term "comprising" (and its grammatical variations) as
used herein is used in the inclusive sense of "having" or
"including," with which it may be used interchangeably. These terms
are not to be construed as being used in the exclusive sense of
"consisting only of" unless explicitly so stated.
[0119] Other than where expressly indicated, all numbers expressing
quantities of ingredients and/or reaction conditions are to be
understood as being modified in all instances by the term "about."
This includes terms such as "all" or "none" and variants thereof.
As used herein, the modifier "about" means within the limits that
one of skill in the art would expect with regard to the particular
quantity defined; this may be, for example, in various embodiments,
+10% of the indicated number, .+-.5% of the indicated number, +2%
of the indicated number, +1% of the indicated number, +0.5% of the
indicated number, or +0.1% of the indicated number.
[0120] Additionally, where ranges are given, it is understood that
the endpoints of the range define additional embodiments, and that
subranges including those not expressly recited are also intended
to include additional embodiments.
[0121] As used herein, "formed from," "generated by," and
variations thereof, mean obtained from chemical reaction of,
wherein "chemical reaction," includes spontaneous chemical
reactions and induced chemical reactions. As used herein, the
phrases "formed from" and "generated by" are open ended and do not
limit the components of the composition to those listed.
[0122] The compositions and methods according to the present
disclosure can comprise, consist of, or consist essentially of the
elements and limitations described herein, as well as any
additional or optional ingredients, components, or limitations
described herein or otherwise known in the art.
[0123] It should be understood that, unless explicitly stated
otherwise, the steps of various methods described herein may be
performed in any order, and not all steps must be performed, yet
the methods are still intended to be within the scope of the
disclosure.
[0124] It will be appreciated that variants of the above-disclosed
and other features and functions, or alternatives thereof, may be
combined into many other different systems or applications. Various
presently unforeseen or unanticipated alternatives, modifications,
variations, or improvements therein may be subsequently made by
those skilled in the art which are also intended to be encompassed
by the following claims.
* * * * *