U.S. patent application number 14/588635 was filed with the patent office on 2015-07-09 for super-hydrophobic fiber having needle-shaped nano structure on its surface, method for fabricating the same and fiber product comprising the same.
The applicant listed for this patent is KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY. Invention is credited to Won Jin JO, Do Hyun KIM, Tae Jun KO, Heon Ju LEE, Jeong Sim LEE, Myoung Woon MOON, Kyu Hwan OH, Eu Sun YU.
Application Number | 20150191868 14/588635 |
Document ID | / |
Family ID | 53494722 |
Filed Date | 2015-07-09 |
United States Patent
Application |
20150191868 |
Kind Code |
A1 |
LEE; Heon Ju ; et
al. |
July 9, 2015 |
SUPER-HYDROPHOBIC FIBER HAVING NEEDLE-SHAPED NANO STRUCTURE ON ITS
SURFACE, METHOD FOR FABRICATING THE SAME AND FIBER PRODUCT
COMPRISING THE SAME
Abstract
A super-hydrophobic fiber of the present disclosure includes: a
nano-needle fiber having a surface including needle-shaped nano
structures; and a coating layer disposed on the surface including
the nano structures, and containing a hydrophobic material. The
fiber has no aging effect, and thus, is excellent in durability,
and has such a large contact angle and such as small sliding angle
that the fiber may not be wet with water. A method for fabricating
the super-hydrophobic fiber includes: a preparation step of
preparing a pre-treating fiber; an etching step of etching a
surface and an inner portion of the pre-treating fiber to fabricate
a nano-needle fiber having a surface on which needle-shaped nano
structures are formed; and a coating step of forming a coating
layer containing a hydrophobic material, and enables mass
production and is performed by simple processes. Further, an
article including the super-hydrophobic fiber is an article in
which no liquid drop is absorbed, scarcely adsorbs a contaminant,
needs not be dried, and thus, may be widely applied even to
recreational articles.
Inventors: |
LEE; Heon Ju; (Seoul,
KR) ; MOON; Myoung Woon; (Seoul, KR) ; LEE;
Jeong Sim; (Seoul, KR) ; YU; Eu Sun; (Seoul,
KR) ; JO; Won Jin; (Seoul, KR) ; KIM; Do
Hyun; (Seoul, KR) ; OH; Kyu Hwan; (Seoul,
KR) ; KO; Tae Jun; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY |
Seoul |
|
KR |
|
|
Family ID: |
53494722 |
Appl. No.: |
14/588635 |
Filed: |
January 2, 2015 |
Current U.S.
Class: |
428/391 ; 216/7;
428/375; 428/394; 428/395 |
Current CPC
Class: |
D06M 10/025 20130101;
Y10T 428/2933 20150115; D06M 11/53 20130101; D06M 2200/12 20130101;
D06M 15/256 20130101; D06M 13/513 20130101; Y10T 428/2969 20150115;
D06M 11/73 20130101; D06M 11/80 20130101; Y10T 428/2967 20150115;
Y10T 428/2962 20150115; D06M 10/08 20130101; D06M 10/06
20130101 |
International
Class: |
D06M 13/513 20060101
D06M013/513; D06M 10/02 20060101 D06M010/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 3, 2014 |
KR |
10-2014-0000891 |
Claims
1. A super-hydrophobic fiber comprising: a nano-needle fiber having
a surface comprising needle-shaped nano structures; and a coating
layer disposed on the surface comprising needle-shaped nano
structures; wherein the needle shaped nano structure has a height
of 50 to 150 nm and a width of 5 to 20 nm, and the surface
comprising needle-shaped nano structures comprises 2 million to 4
million needle-shaped nanostructures per 1 mm.sup.2 of an area.
2. The super-hydrophobic fiber of claim 1, wherein the
needle-shaped nano structures are formed on the outermost surface
of a pre-treating fiber and at the inner surface portion which is
up to 100 .mu.m deep from the outermost surface.
3. The super-hydrophobic fiber of claim 1, wherein the
super-hydrophobic fiber is one material selected from the group
consisting of polyester, polyurethane, polyamide, polyvinyl
alcohol, polyvinyl chloride, polyvinylidene chloride,
acrylonitrile, polypropylene, polyacryl, and a combination
thereof.
4. The super-hydrophobic fiber of claim 1, wherein the coating
layer has a thickness of 5 to 100 nm.
5. The super-hydrophobic fiber of claim 1, wherein the hydrophobic
material is one selected from the group consisting of
hexamethyldisiloxane (HMDSO), molybdenum disulfide (MoS.sub.2),
boron nitride (BN), polytetra fluoroethylene (PTFE), fluorinated
diamond like carbon (F-DLC), and a combination thereof.
6. The super-hydrophobic fiber of claim 1, wherein the
super-hydrophobic fiber has a contact angle of 150 degree or more
with pure water.
7. The super-hydrophobic fiber of claim 1, wherein the
super-hydrophobic fiber has a sliding angle of 3 degree or
less.
8. A method for fabricating super-hydrophobic fiber, the method
comprising: a preparation step of preparing a pre-treating fiber to
be subjected to super-hydrophobic treatment; an etching step of
etching an outermost surface of the pre-treating fiber and an inner
surface portion which is 100 .mu.m deep from the outermost surface
to fabricate a nano-needle fiber having a surface on which
needle-shaped nano structures are formed; and a coating step of
forming a coating layer containing a hydrophobic material on the
surface on which nano structures of the fiber are formed.
9. The method of claim 8, wherein he etching step is one method
selected from the group consisting of plasma etching, reactive ion
etching, ion-milling, electro discharge machining (EDM), and a
combination thereof.
10. The method of claim 9, wherein the plasma etching is performed
for 30 sec to 90 min while a reactive gas is included, and the
reactive gas is one selected from the group consisting of CF.sub.4,
CHF.sub.3, C.sub.2F.sub.6, C.sub.2Cl.sub.2F.sub.4, C.sub.3F.sub.8,
C.sub.4F.sub.8, SF.sub.6, O.sub.2, and a mixture thereof.
11. The method of claim 10, wherein the plasma etching is performed
under conditions of a pressure of 10 to 100 mTorr, an rf-power of
100 to 400 W, and a bias voltage of 300 to 500 V for 5 min to 40
min.
12. The method of claim 8, wherein in the coating step, a coating
layer containing a hydrophobic material is formed by one selected
from the group consisting of Plasma Enhanced Chemical Vapor
Deposition (PECVD), Atmospheric Chemical Vapor Deposition (APCVD),
Low Pressure Chemical Vapor Deposition (LPCVD), Metal-Organic
Chemical Vapor Deposition (MOCVD), Ultra-high vacuum Chemical Vapor
Deposition (UHCVD), Atomic Layer Deposition (ALD), and a
combination thereof.
13. The method of claim 8, wherein the coating step is performed by
plasma enhanced chemical vapor deposition (PECVD), and is performed
under conditions of a pressure of 5 to 30 mTorr, an rf-power of 150
to 400 W, and a bias voltage of 300 to 500 V.
14. The method of claim 8, wherein the needle-shaped nano structure
has a height of 50 to 150 nm and a width of 5 to 20 nm, and
comprises 2 million to 4 million needles per 1 mm.sup.2 of a
surface area of the fiber.
15. The method of claim 8, wherein the fiber is one selected from
the group consisting of polyester, polyurethane, polyamide,
polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride,
acrylonitrile, polypropylene, polyacryl, and a combination
thereof.
16. The method of claim 8, wherein the hydrophobic material is one
selected from the group consisting of hexamethyldisiloxane (HMDSO),
molybdenum disulfide (MoS.sub.2), boron nitride (BN), polytetra
fluoroethylene (PTFE), fluorinated diamond like carbon (F-DLC), and
a combination thereof.
17. A fiber product comprising: a nano-needle fiber having a
surface comprising needle-shaped nano structures; and a coating
layer disposed on the surface comprising needle-shaped
nanostructures, and containing a hydrophobic material; wherein the
needle-shaped nano structure has a height of 50 to 150 nm and a
width of 5 to 20 nm, and comprises 2 million to 4 million needles
per 1 mm.sup.2 of a surface area of the fiber.
18. The fiber product of claim 17, wherein the fiber product is one
selected from the group consisting of a tent, an umbrella, shoes, a
banner, a cap, a bag, a knapsack, and clothes.
Description
CROSS-REFERENCE TO RELATED APPLICAION
[0001] Pursuant to 35 U.S.C. .sctn.119(a), this application claims
the benefit of earlier filing date and right of priority to Korean
Application No. 10-2014-0000891, filed on Jan. 3, 2014, the
contents of which is incorporated by reference herein in its
entirety.
BACKGROUND OF THE DISCLOSURE
[0002] 1. Field of the Disclosure
[0003] The present disclosure relates to super-hydrophobic fiber
having a surface including needle-shaped nano structures and in
which a coating layer containing a hydrophobic material is formed
on the surface, a method for fabricating the same, and a fiber
product comprising the same.
[0004] 2. Background of the Disclosure
[0005] In order to impart a hydrophobic or contamination prevention
function to the conventional functional clothing, methods of
coating a material having a low surface energy, such as hydrophobic
Teflon have been adopted. Further, International Publication No. WO
2012/152997 discloses a method of forming a super-hydrophobic
surface having a nano structure including: applying a solution
obtained by mixing nanocellulose particles on the surface by a
spray method, and evaporating moisture from the applied solution,
but since a hydrophobic solution is applied by a spray method, it
is difficult to form a uniform coating layer, and there is a
problem in that due to the separation of particles introduced for
forming a hydrophobic surface from the surface, contamination, or
deterioration in hydrophobic characteristics easily occurs.
[0006] As another example, the document [M. Joshi, et al., Nano
structured coatings for super hydrophobic textiles, Bulletin of
Materials Science] suggests a method of forming a surface with a
low surface energy having a nano structure by depositing silica
nanoparticles on fabric, but since there is a concern in that the
particles may be subsequently desorbed due to using a method of
depositing particles, there is a limitation in durability, and
there is a problem in that contamination caused by particle dust
may occur or performance may deteriorate.
[0007] As described above, in the case of a method of directly
depositing the nano structure on fiber such as fabric, the
deposited material is desorbed, or the coating layer is easily worn
due to weak durability, and as a result, the performance may
rapidly deteriorates, and contamination and the like due to
desorbed particles may lead to problems.
[0008] In addition, these methods may have environmental
contamination due to waste water by using solutions and the like in
the fabrication process, and also have problems in that the process
is complicated, process costs are increased, and it is a little
difficult to achieve mass production.
SUMMARY OF THE DISCLOSURE
[0009] Therefore, an aspect of the detailed description is to
provide super-hydrophobic fiber in which super-hydrophobicity,
which does not make the surface wet, is maintained without aging
effects for a long period of time by imparting durable
super-hydrophobicity to the surface of fiber (or fabric) such as
polyester, a method for fabricating the same, and a fiber product
comprising the same. The fabricating method has
environmentally-friendly production processes, is inexpensive in
terms of fabrication costs and may be applied to fibers, fabrics
and the like made of various materials, and may also be applied to
commercialized fibers.
[0010] The super-hydrophobic fiber according to an exemplary
embodiment of the present disclosure includes: a nano-needle fiber
having a surface including needle-shaped nano structures; and a
coating layer disposed on the surface including the needle-shaped
nano structures and containing a hydrophobic material.
[0011] The needle-shaped nano structure may have a height of 50 to
150 nm and a width of 5 to 20 nm, and the surface including the
needle-shaped nano structures may include 2 million to 4 million
needle-shaped nano structures per 1 mm.sup.2 of an area.
[0012] The needle-shaped nano structures may be formed on the
outermost surface of a pre-treating fiber and at the inner surface
portion which is up to 100 .mu.m deep from the outermost
surface.
[0013] The super-hydrophobic fiber may be one material selected
from the group consisting of polyester, polyurethane, polyamide,
polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride,
acrylonitrile, polypropylene, polyacryl, and a combination
thereof.
[0014] The coating layer may have a thickness of 5 to 100 nm, and
the hydrophobic material may be one selected from the group
consisting of hexamethyldisiloxane (HMDSO), molybdenum disulfide
(MoS.sub.2), boron nitride (BN), polytetra fluoroethylene (PTFE),
fluorinated diamond like carbon (F-DLC), and a combination
thereof.
[0015] The super-hydrophobic fiber may have a contact angle of 150
degree or more with pure water, and a sliding angle of 3 degree or
less with pure water.
[0016] A method for fabricating super-hydrophobic fiber according
to another exemplary embodiment of the present disclosure includes:
a preparation step of preparing a pre-treating fiber to be
subjected to super-hydrophobic treatment; an etching step of
etching an outermost surface of the pre-treating fiber and an inner
surface portion which is 100 .mu.m deep from the outermost surface
to fabricate a nano-needle fiber having a surface on which
needle-shaped nano structures are formed; and a coating step of
forming a coating layer containing a hydrophobic material on the
surface on which nano structures of the fiber are formed.
[0017] The etching step may be one method selected from the group
consisting of plasma etching, reactive ion etching, ion-milling,
electro discharge machining (EDM), and a combination thereof.
[0018] The plasma etching may be performed for 30 sec to 90 min
while a reactive gas is included, and the reactive gas may be one
selected from the group consisting of CF.sub.4, CHF.sub.3,
C.sub.2F.sub.6, C.sub.2Cl.sub.2F.sub.4, C.sub.3F.sub.8,
C.sub.4F.sub.8, SF.sub.6, O.sub.2, and a mixture thereof, and the
plasma etching may be performed under conditions of a pressure of
10 to 100 mTorr, an rf-power of 100 to 400 W, and a bias voltage of
300 to 500 V for 5 min to 40 min.
[0019] In the coating step, a coating layer containing a
hydrophobic material may be formed by one selected from the group
consisting of plasma enhanced chemical vapor deposition (PECVD),
atmospheric chemical vapor deposition (APCVD), low pressure
chemical vapor deposition (LPCVD), metal-organic chemical vapor
deposition (MOCVD), ultra-high vacuum chemical vapor deposition
(UHCVD), atomic layer deposition (ALD), and a combination
thereof.
[0020] The coating step may be performed by plasma enhanced
chemical vapor deposition (PECVD), and may be performed under
conditions of a pressure of 5 to 30 mTorr, an rf-power of 150 to
400 W, and a bias voltage of 300 to 500 V.
[0021] The needle-shaped nano structure may have a height of 50 to
150 nm and a width of 5 to 20 nm, and may include 2 million to 4
million needles per 1 mm.sup.2 of a surface area of the fiber.
[0022] The fiber may be one selected from the group consisting of
polyester, polyurethane, polyamide, polyvinyl alcohol, polyvinyl
chloride, polyvinylidene chloride, acrylonitrile, polypropylene,
polyacryl, and a combination thereof.
[0023] The hydrophobic material may be one selected from the group
consisting of hexamethyldisiloxane (HMDSO), molybdenum disulfide
(MoS.sub.2), boron nitride (BN), polytetra fluoroethylene (PTFE),
fluorinated diamond like carbon (F-DLC), and a combination
thereof.
[0024] A fiber product according to still another exemplary
embodiment of the present disclosure includes: a nano-needle fiber
having a surface including needle-shaped nano structures; and a
coating layer disposed on the surface including needle-shaped
nanostructures, and containing a hydrophobic material.
[0025] The needle-shaped nano structure have a height of 50 to 150
nm and a width of 5 to 20 nm, the surface may include 2 million to
4 million needle-shaped nano structures per 1 mm.sup.2 of an area,
and the fiber product may be one selected from the group consisting
of a tent, an umbrella, shoes, a banner, a cap, a bag, a knapsack,
and clothes.
[0026] As used herein, the term "include" or "have" indicates that
a feature, a number, a step, a component, and a combination thereof
described in the specification is present, but do not exclude the
possibility of presence or addition of one or more other features,
numbers, steps, components, and combinations thereof, in
advance.
[0027] As used herein, the term "needle-shaped" or "nano needle" is
a term that expresses a nano structure in the form of a nanoscale
needle, and expresses a nano structural body formed on the surface
of a material. The shape of the nano structure may be a polyprism,
a polypyramid, a circular cylinder, a circular cone, and the like,
and may also be a structural body having different areas of the
bottom surface and the top surface.
[0028] Singular or plural expressions used in the present
specification do not limit the number in a specific material, and
may refer to one specific material, or may refer to a group formed
of a specific material. As used herein, the term "pre-treating
fiber" is a fiber in the raw material state before being subjected
to super-hydrophobic treatment and refers to a fiber before being
etched, and the term "nano-needle fiber" refers to a fiber which
has a surface including a needle-shaped nano structure by forming
the needle-shaped nano structure on the surface of a pre-treating
fiber through the etching step.
[0029] Unless otherwise defined herein, the term "fiber" as used
herein is used as a meaning including not only a type of fiber in
the form of yarn, but also a type of fiber included in a raw fabric
having a texture structure such as fabric, knit and unwoven
fabric.
[0030] Hereinafter, the present disclosure will be described in
more detail.
[0031] The super-hydrophobic fiber according to an exemplary
embodiment of the present disclosure includes: a nano-needle fiber
having a surface including needle-shaped nano structures; and a
coating layer disposed on the surface including the needle-shaped
nano structure and containing a hydrophobic material.
[0032] The needle-shaped nano structure may have a height of 50 to
150 nm and a width of 5 to 20 nm, and the surface including the
needle-shaped nano structures may include 2 million to 4 million
needle-shaped nano structures per 1 mm.sup.2 of an area.
[0033] The needle-shaped nano structures may be formed on the
outermost surface of a pre-treating fiber and at the inner surface
portion which is 100 .mu.m, preferably 150 .mu.m, and more
preferably 200 .mu.m deep from the outermost surface, and the
needle-shaped nano structures may be formed on one surface or both
surfaces of the pre-treating fiber. These needle-shaped nano
structures may be formed by, for example, a process of etching at
least one surface of the pre-treating fiber.
[0034] As described above, the needle-shape nano structure is a
structure in which a plurality of protrusions in the form of
nanoscale needle are formed, and the nano structure is formed not
only on the outermost surface of the pre-treating fiber, but also
at a specific inner surface portion from the outermost surface due
to the morphological characteristics of fiber.
[0035] When the nano structure is thus formed not only on the
outermost surface but also at an inner surface portion which is
disposed at a predetermined depth from the outermost surface, the
inner surface portion is safe from wear and tear, so that the aging
effect does not substantially occur, and therefore,
super-hydrophobic fiber, in which super-hydrophobic characteristics
are maintained for a long period of time, may be obtained.
[0036] In general, the hydrophobic surface is formed by a method of
coating a material having a low surface energy. However, when the
method is adopted, hydrophobic characteristics may easily disappear
due to peeling-off of the coated material or contamination by
foreign substances and the like, and this effect refers to an aging
effect. In other words, as time elapses, due to the aging effect
that hydrophobic characteristics imparted to a fiber gradually
disappear, it is difficult for the fiber to steadily maintain
hydrophobic or super-hydrophobic characteristics. However, in the
case of a fiber in which the needle-shaped nano structure is formed
on the surface, the nano structure is formed not only on the
outermost surface of the fiber, and due to the characteristics of
woven form of the fiber, a reactive gas penetrates each fiber yarn
at the time of etching treatment and as a result, needle-shaped
nano structures are formed also at the inner surface portion which
is about 100 to 200 .mu.m deep, and therefore, the aging effect may
be substantially prevented from occurring. For example, even though
the nano structure of the outermost surface is structurally lost
due to friction and the like, another nano structure is present at
the inner surface portion which is safe from wear and tear and
super-hydrophobic characteristics may be maintained for this
reason, and therefore, the structural durability is excellent, and
thus, super-hydrophobicity may be maintained for a long period of
time.
[0037] The material for the hydrophobic fiber may be unwoven
fabric, fabric, or knit. First, the fiber may be applied as long as
the fiber is a polymer fiber which is easily etched, a
carbon-containing polymer may be advantageous, and examples of the
polymer include polyester-based, polyacryl-based,
polyurethane-based, and polypropylene-based polymer fibers.
Examples of specifically applicable polymer fiber include fiber
including polyester, polyurethane, polyamide, polyvinyl alcohol,
polyvinyl chloride, polyvinylidene chloride, acrylonitrile,
polypropylene, or polyacryl, and the like, but the polymer fiber is
not limited thereto.
[0038] For the polymer fiber, as long as the polymer fiber may
easily form a nano structure, and will be used in a fiber product
which requires super-hydrophic processes, super-hydrophobic fiber
may be prepared by a method including forming the needle-shaped
nano structure, and forming a coating layer and then may be
applied, and be applicable to various fiber products. Examples of
the applicable fiber product include clothing, a bag, an umbrella,
a tent, a raincoat, shoes, a cap, a knapsack, a swimsuit, a banner,
and the like.
[0039] The coating layer formed on the nano-needle fiber may have a
thickness of 5 to 100 nm. When the thickness of the coating layer
is 5 nm or less, the coating layer is so thin that additional
hydrophobic characteristics may not be properly imparted and
durability may deteriorate, and when the thickness of the coating
layer exceeds 100 nm, each gap between the needle-shaped nano
structures may be all filled with a coating material, so that
super-hydrophobic characteristics due to the formation of the nano
structure may deteriorate.
[0040] The hydrophobic material may be, for example, one selected
from the group consisting of hexamethyldisiloxane (HMDSO),
molybdenum disulfide (MoS.sub.2), boron nitride (BN), polytetra
fluoroethylene (PTFE), and a combination thereof, and it is also
possible to use a diamond like carbon (DLC) material, or a material
obtained by subjecting the aforementioned material to fluorization
treatment. The aforementioned materials have high strength and
excellent friction resistance, and thus may further enhance
durability of the super-hydrophobic surface. It is preferred that
as the hydrophobic material, hexamethyldisiloxane is applied.
[0041] The super-hydrophobic fiber may have a contact angle of 150
degree or more with pure water, and a sliding angle of 3 degree or
less, preferably 2 degree or less with pure water. Here, the
contact angle with pure water means an angle between a surface at
the inner side of a liquid and a surface of a solid when a liquid
drop of water containing no impurity, that is, water treated with
an ion exchange resin is brought into contact with the solid, and
the sliding angle with pure water means an angle between a tilted
solid and a horizontal surface when a liquid drop of the water
containing no impurity begins to tilt the solid while being in
contact with the solid, and then begins to slide down.
[0042] When the super-hydrophobic fiber has the contact angle and
the sliding angle within the aforementioned ranges, the surface of
the fiber is super-hydrophobic, so that the fiber is not
substantially wet even though the fiber is in contact with water,
and slightly contaminated or seldom contaminated even though the
fiber is in contact with a contaminant, and even though the
contaminant or water is contact with the super-hydrophobic fiber,
the contaminant or water is easily desorbed, and as a result, the
fiber remains for a long period of time not being wet with water or
not contaminated.
[0043] The fiber having these characteristics may be used for an
umbrella, a raincoat, outdoor clothing (mountain-climbing clothes,
ski clothes, and the like), shoes, a cap, a swimsuit, a bag, a
knapsack and the like, thereby providing a functional fiber product
having characteristics that the fiber is not wet with water, or is
not easily contaminated.
[0044] A method for fabricating super-hydrophobic fiber according
to another exemplary embodiment of the present disclosure includes:
a preparation step of preparing a pre-treating fiber to be
subjected to super-hydrophobic treatment; an etching step of
etching an outermost surface of the pre-treating fiber and an inner
surface portion which is 100 .mu.m, preferably 150 .mu.m, and more
preferably 200 .mu.m deep from the outermost surface to fabricate a
nano-needle fiber having a surface on which needle-shaped nano
structures are formed; and a coating step of forming a coating
layer containing a hydrophobic material on the surface on which
nano structures of the fiber are formed. FIG. 1 is a conceptual
view describing an example of the method of fabricating
super-hydrophobic fiber of the present disclosure step by step, and
illustrates a pre-treating fiber, a (dry etching-treated)
nano-needle fiber, and a (hydrophobically coated) super-hydrophobic
fiber, in order from the top down.
[0045] Since the explanation for the raw material for the fiber,
the hydrophobic material, the coating layer containing the
hydrophobic material, the needle-shaped nano structure, and
characteristics and advantages of the super-hydrophobic fiber, and
the like is identical to that as described above, the description
thereof will be omitted.
[0046] The etching step may be a step of etching an outermost
surface of the pre-treating fiber and an inner surface portion
which is about 100 .mu.m to 200 .mu.m deep from the outermost
surface by one or more etching methods to form needle-shaped nano
structures on the outermost surface and at the inner surface
portion. FIG. 1 illustrates etching only one surface of the woven
fiber, but the etching may be performed on one surface or both
surfaces of the pre-treating fiber, and need-shape nano structures
may be formed on the outermost surface and at the inner surface
portion of fiber strands disposed on the etched surface.
[0047] The etching method may be performed by one method selected
from the group consisting of plasma etching, reactive ion etching,
ion-milling, electro discharge machining (EDM), and a combination
thereof. Preferably, the etching may be performed by plasma
etching.
[0048] Any plasma etching may be applied without limitation as long
as the plasma etching is performed using plasma, and may be
performed for 30 sec to 90 min by including a reactive gas, and any
reactive gas may be applied as long as the reactive gas may be used
for etching and does not excessively damage the fiber, and the
reactive gas may be, for example, one selected from the group
consisting of CF.sub.4, CHF.sub.3, C.sub.2F.sub.6,
C.sub.2Cl.sub.2F.sub.4, C.sub.3F.sub.8, C.sub.4F.sub.8, SF.sub.6,
O.sub.2, and a mixture thereof.
[0049] With respect to the conditions under which the plasma
etching is performed, the pressure may be 10 to 100 mTorr, the
rf-power may be 100 to 400 W, the bias voltage may be 300 to 500 V,
and time may be 30 sec to 90 min, preferably 5 min to 40 min. When
the etching is performed with the numerical ranges of the
conditions, a nano-shaped structure with an appropriate size may be
formed on the fiber.
[0050] All of the etching methods are a dry etching method, and do
not use an etchant, and therefore, the methods are a method which
is environmentally-friendly due to low emission of hazardous
materials, may reduce process costs due to the simple processes,
and enables mass production due to ability to process a large area.
The coating step may be a step of forming a coating layer
containing a hydrophobic material by one coating method, and as
illustrated in the bottom of FIG. 1, it is preferred that a method
capable of forming a coating layer on the needle-shaped nano
structures which are a nanoscale structural body is applied to the
coating method. As the coating method, it is possible to apply, for
example, plasma enhanced chemical vapor deposition (PECVD),
atmospheric chemical vapor deposition (APCVD), low pressure
chemical vapor deposition (LPCVD), metal-organic chemical vapor
deposition (MOCVD), ultra-high vacuum chemical vapor deposition
(UHCVD), or atomic layer deposition (ALD). Preferably, plasma
enhanced chemical vapor deposition (PECVD) may be applied to the
coating step, and when a coating layer is formed on the nano
structure by this deposition method, it is possible to prepare
super-hydrophobic fiber in which super-hydrophobicity is well
maintained.
[0051] As the conditions under which the plasma chemical vapor
deposition is performed, the pressure may be 5 to 30 mTorr, the
rf-power may be 150 to 400 W, and the bias voltage may be 300 to
500 V, and only when the deposition is performed within the
aforementioned range, a coating layer with an appropriate thickness
may be formed, thereby fabricating super-hydrophobic fiber having a
super-hydrophobic coating layer formed thereon while maintaining
needle-like nano structures.
[0052] A fiber product including super-hydrophobic fiber according
to still another exemplary embodiment of the present disclosure
includes a fiber including: a nano-needle fiber having a surface
including needle-shaped nano structures; and a coating layer
disposed on the surface including needle-shaped nanostructures, and
containing a hydrophobic material.
[0053] Since the explanation for the raw material for the fiber,
the hydrophobic material, the coating layer containing the
hydrophobic material, the needle-shaped nano structure, and
characteristics and advantages of the super-hydrophobic fiber, and
the like is identical to that as described above, the description
thereof will be omitted.
[0054] The fiber product may be, for example, a raw fabric for a
tent, a raw fabric for an umbrella, a raw fabric for shoes, a
banner, a raw fabric for a cap, a raw fabric for a bag or a
knapsack, clothing, or a combination thereof. The fiber product may
be a raw fabric for an umbrella, and when the raw fabric for an
umbrella is made of the super-hydrophobic fiber, a liquid drop such
as a raindrop is rarely absorbed in the raw fabric, and as a
result, the umbrella is not wet, and needs not be dried after the
umbrella is used. Further, since an umbrella tray, a plastic bag
for storing an umbrella and the like are not required for a rainy
day any more, convenience of life in a rainy day may be further
improved.
[0055] In addition to the umbrella, the fiber products fabricated
by including the super-hydrophobic fiber as described above may
remove inconvenience occurring and need for incidental auxiliary
articles if the product are wet, and accordingly, social costs may
be reduced, and the fiber products may also be applied to various
fields.
[0056] Since the super-hydrophobic fiber of the present disclosure
has such a large contact angle and such a small sliding angle that
the fiber has a needle-shaped nano structure in which a liquid drop
is not absorbed, and super-hydrophobicity may be maintained without
an aging effect for a long period of time, durability is excellent,
and super-hydrophobic characteristics may be maintained for a long
period of time. In addition, the method for fabricating
super-hydrophobic fiber of the present disclosure may be easily
applied to the industry because the processes are simple, mass
production may be achieved, and hazardous materials such as an
etchant are not used.
[0057] Furthermore, the article including the super-hydrophobic
fiber is an article in which a liquid drop is not absorbed at all
and needs not be dried, and when the article is used as an umbrella
or a raincoat in a rainy day, hygienically necessary incidental
articles, such as an umbrella storage box and a plastic bag for
storing an umbrella, are not required any more, and as a result,
social costs may be reduced, and the articles may also be applied
to various recreational articles in addition to this purpose.
BRIEF DESCRIPTION OF THE DRAWINGS
[0058] The accompanying drawings, which are included to provide a
further understanding of the disclosure and are incorporated in and
constitute a part of this specification, illustrate exemplary
embodiments and together with the description serve to explain the
principles of the disclosure.
[0059] In the drawings:
[0060] FIG. 1 is a conceptual view describing an example of the
method of fabricating super-hydrophobic fiber of the present
disclosure step by step, and illustrates a pre-treating fiber, a
(dry etching-treated) nano-needle fiber, and a (hydrophobically
coated) super-hydrophobic fiber, in order from the top down.
[0061] FIG. 2 is a low-magnification photograph of pre-treating
fiber taken by scanning electron microscope (SEM).
[0062] FIG. 3 is intermediate-magnification and high-magnification
photographs of pre-treating fiber taken by scanning electron
microscope (SEM).
[0063] FIG. 4 is intermediate-magnification and high-magnification
photographs of nano-needle fiber taken by scanning electron
microscope (SEM).
[0064] FIG. 5 is photographs taken when a liquid drop is placed on
the surface of the pre-treating fiber (left) and on the surface of
super-hydrophobic fiber which is an exemplary embodiment of the
present disclosure (right).
[0065] FIG. 6 is a graph showing the results obtained by measuring
the contact angles of the pre-treating fiber and the
super-hydrophobic fiber which is an exemplary embodiment of the
present disclosure.
[0066] FIG. 7 is a graph showing the results obtained by measuring
the contact angles and sliding angles of the super-hydrophobic
fiber which is an exemplary embodiment of the present disclosure
immediately after the fabrication and after elapse of 80 days after
the fabrication.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0067] Description will now be given in detail of the exemplary
embodiments, with reference to the accompanying drawings. For the
sake of brief description with reference to the drawings, the same
or equivalent components will be provided with the same reference
numbers, and description thereof will not be repeated.
[0068] Hereinafter, exemplary embodiments of the present disclosure
will be described in detail with reference to the accompanying
drawings, such that those skilled in the art to which the present
disclosure pertains can easily carry out the invention. However,
the present disclosure can be implemented in various different
forms, and is not limited to the exemplary embodiments described
herein.
EXAMPLE.
Fabrication of Hydrophobic Fiber
Preparation Example 1. Fabrication of Nano-Needle Fiber
[0069] A polyester fabric was used as pre-treating fiber, and
hexamethyldisiloxane was used as a hydrophobic material. First, the
polyester fabric was etched for about 30 min using an ion-beam
etching device by a plasma etching method (dry etching) using
O.sub.2 as a reactive gas under conditions of a pressure of 20
mTorr, an oxygen flow rate of 10 sccm, an RF-power of 250 W, and a
bias voltage of 400V, thereby fabricating a nano-needle fiber
having a surface including needle-shaped nano structures, as
illustrated in the middle of FIG. 1.
Preparation Example 2. Fabrication of Super-Hydrophobic Fiber
[0070] Plasma enhanced chemical vapor deposition (PECVD) was used
to perform a plasma treatment on the surface (on the surface of the
nano-needle fiber) of needle-shaped nano structures in Preparation
Example 1 for about 15 sec while hexamethyldisiloxane was allowed
to flow at 10 sccm under conditions of a pressure of 10 mTorr, an
RF-power of 250 W, and a bias voltage of 400 V, and a coating layer
including hexamethyldisiloxane as a hydrophobic material was formed
as illustrated in the bottom of FIG. 1, thereby fabricating
super-hydrophobic fiber.
[0071] FIGS. 2 and 3 are photographs of the surface of the
pre-treating fiber before the etching step was performed, taken at
various magnifications by using a scanning electron microscope. It
can be seen that the pre-treating fiber before the etching step was
performed had a significantly smooth surface. However, FIG. 4 is
photographs of the surface of the nano-needle fiber after the
etching step was performed, taken by scanning electron microscope,
and it can be confirmed that needle-shaped nano structures were
formed on the surface of the nano-needle fiber.
Experimental Example. Evaluation of Super-Hydrophobic Fiber
[0072] 1. Evaluated Physical Properties and Measurement Method
[0073] The contact angle of the super-hydrophobic fiber fabricated
in the Example was measured using NRL Contact Angle Goniometer. The
contact angle was measured by a method including: aligning the base
line of the fiber, slightly dropping a liquid drop thereon, and
then rotating a goniometer to read a measured angle. The contact
angle measurement photograph was taken by using a GBX machine.
Further, the sliding angle of the super-hydrophobic fiber was
measured by using a high speed camera. The sliding angle was
measured by a method including: aligning the base line of the
fiber, slightly dropping a liquid drop thereon, and then reading an
angle between the tilted fiber and the horizontal plane when the
liquid drop began to flow while the fiber was slowly slanted, and
the sliding angle measurement photograph was taken by using a high
speed camera.
[0074] 2. Evaluation of Wettability of Pre-Treating Fiber and
Super-Hydrophobic Fiber
[0075] Referring to FIG. 5, it can be confirmed that a liquid drop
was almost absorbed in the pre-treating fiber illustrated in the
left photograph, whereas the liquid drop was scarcely absorbed in
the super-hydrophobic fiber of the present disclosure illustrated
in the right photograph while almost maintaining a spherical shape.
In addition, referring to the graph in FIG. 6, it can be confirmed
that the pre-treating fiber had a contact angle of about 50 degree
as observed in the left photograph of FIG. 5, whereas the fiber had
a contact angle of about 150 degree, which is a significantly large
value after the method of the present disclosure was performed.
[0076] 3. Evaluation of Durability of Super-Hydrophobic Fiber
(Evaluation of Aging Effect)
[0077] The contact angle and sliding angle of the super-hydrophobic
fiber were measured immediately after the method of the present
disclosure had been performed, and the contact angle and sliding
angle of the super-hydrophobic fiber were measured after 80 days
elapsed. The device and the method, which are the same as in the
device of measuring a contact angle, were applied to the
measurement of the sliding angle. As a result, referring to FIG. 7,
when comparing the case immediately after the method had been
performed with the case after 80 days elapsed, it can be seen that
the sliding angle was slightly increased, but the result of the
contact angle was almost the same as the initial result, and
through this, it can be confirmed that the super-hydrophobic fiber
of the present disclosure is also excellent in durability.
[0078] While preferred embodiments of the present disclosure have
been described in detail, it is to be understood that the scope of
the present disclosure is not limited thereto, and various
modifications and variations made by those skilled in the art using
basic concepts of the present disclosure defined in the following
claims also fall within the scope of the present disclosure.
[0079] The foregoing embodiments and advantages are merely
exemplary and are not to be considered as limiting the present
disclosure. The present teachings can be readily applied to other
types of apparatuses. This description is intended to be
illustrative, and not to limit the scope of the claims. Many
alternatives, modifications, and variations will be apparent to
those skilled in the art. The features, structures, methods, and
other characteristics of the exemplary embodiments described herein
may be combined in various ways to obtain additional and/or
alternative exemplary embodiments.
[0080] As the present features may be embodied in several forms
without departing from the characteristics thereof, it should also
be understood that the above-described embodiments are not limited
by any of the details of the foregoing description, unless
otherwise specified, but rather should be considered broadly within
its scope as defined in the appended claims, and therefore all
changes and modifications that fall within the metes and bounds of
the claims, or equivalents of such metes and bounds are therefore
intended to be embraced by the appended claims.
* * * * *