This application claims all benefits accruing under 35 U.S.C. §119 from China Patent Application No. 201420199680.X, field on Apr. 23, 2014 in the China Intellectual Property Office, disclosure of which is incorporated herein by reference. The application is also related to copending applications entitled, “BINDING WIRE AND SEMICONDUCTOR PACKAGE STRUCTURE USING THE SAME”, filed ______ (Atty. Docket No. US56061); “CARBON NANOTUBE COMPOSITE WIRE”, filed ______ (Atty. Docket No. US56063); “HOT WIRE ANEMOMETER”, filed ______ (Atty. Docket No. US56064); “DEFROSTING GLASS, DEFROSTING LAMP AND VEHICLE USING THE SAME”, filed ______ (Atty. Docket No. US56065); “WIRE CUTTING ELECTRODE AND WIRE CUTTING DEVICE USING THE SAME”, filed ______ (Atty. Docket No. US56066); “CONDUCTIVE MESH AND TOUCH PANEL USING THE SAME”, filed ______ (Atty. Docket No. US56067); “MASS FLOWMETER”, filed ______ (Atty. Docket No. US56069).
The disclosure generally relates to an electromagnetic shielding material, and clothing using the electromagnetic shielding material.
Studies have shown that long-term, excessive electrostatic and electromagnetic radiation will cause direct damage to human reproductive system, nervous system and immune system, which is the major cause of cardiovascular disease, diabetes and cancer. Long-term, excessive electrostatic and electromagnetic radiation can directly affect the growth of body tissues and bone in children. Additionally, long-term, excessive electrostatic and electromagnetic radiation can also cause a decline of vision, memory and liver hematopoiesis. Electrostatic radiation and electromagnetic radiation have become a fourth major pollution following air pollution, water pollution and noise pollution. As such, a protection from the electrostatic and electromagnetic radiation becomes urgent.
Implementations of the present technology will now be described, by way of example only, with reference to the attached figures.
It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the present disclosure.
Several definitions that apply throughout this disclosure will now be presented.
The term “substantially” is defined to be essentially conforming to the particular dimension, shape, or other feature that the term modifies, such that the component need not be exact. For example, “substantially cylindrical” means that the object resembles a cylinder, but can have one or more deviations from a true cylinder. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like.
The substrate 11 can be made of cotton, hemp, fiber, nylon, spandex, polyester, polyacrylonitrile, wool, silk, and the like. The fiber includes carbon fiber, chemical fiber, rayon, and so on. In one embodiment, the substrate 11 is made of rayon.
The substrate 11 is used to support the shield layer 12. The substrate 11 and the shield layer 12 can be sewn together or bonded together with an adhesive. In one embodiment, a waterproof adhesive can be used, thereby allowing washing of the electromagnetic shielding material 100 without degrading the bond.
The shield layer 12 includes a carbon nanotube structure; the carbon nanotube structure includes a plurality of carbon nanotubes forming a conductive closed circuit. Because carbon nanotubes have excellent conductivity, when a part of carbon nanotubes of the conductive closed circuit cuts magnetic induction lines in a magnetic field, a magnetic flux of the conductive closed circuit will be changed, and an induction electromotive force and an induced current will be produced in the electrically conductive closed circuit, thereby producing a reverse electromagnetic field for shielding the external magnetic field.
Since the carbon nanotubes have excellent conductivity, when an electric field intensity of a surface of the conductive closed circuit exceeds a critical value, original ions in air will have sufficient kinetic energy. The original ions can impact uncharged molecules in air and make them ionize, which can make the air partially conductive; thereby producing a corona discharge. The corona discharge can eliminate external charge, thereby achieving an anti-radiation and anti-static effect. Additionally, the carbon nanotubes have excellent conductivity, which can reduce a surface resistivity of the substrate 11 by forming a conductive layer on the surface of the substrate 11; thus electrostatic charge that has been generated can be quickly discharged, thereby improving the anti-radiation and anti-static effect.
A plurality of holes can be formed between the plurality of carbon nanotubes of the carbon nanotube structure. In one embodiment, a size of the holes is less than a quarter of a wavelength of an electromagnetic wave. In one embodiment, the size of the holes ranges from about 20 nm to about 400 nm.
The carbon nanotube structure includes at least one carbon nanotube wire, at least one carbon nanotube composite wire, at least one carbon nanotube film, and/or at least one carbon nanotube composite film. The arrangement of the carbon nanotube wire, the carbon nanotube composite wire, the carbon nanotube film, and the carbon nanotube composite film are not limited, as long as the carbon nanotube structure form a conductive closed circuit.
The carbon nanotube wire can be an untwisted carbon nanotube wire or a twisted carbon nanotube wire.
In one embodiment, the twisted carbon nanotube wire 15 has an S twist or a Z twist. During the twisting process of the carbon nanotube film, a space between adjacent carbon nanotubes becomes smaller along a radial direction of the twisted carbon nanotube wire 15, and a contact area between the adjacent carbon nanotubes becomes larger along the radial direction of the twisted carbon nanotube wire 15. Therefore, van der Waals attractive force between adjacent carbon nanotubes along the radial direction of the twisted carbon nanotube wire 15 significantly increases, and adjacent carbon nanotubes in the twisted carbon nanotube wire 15 are closely connected. In one embodiment, the space between adjacent carbon nanotubes along the radial direction of the twisted carbon nanotube wire 15 is less than or equal to 10 nanometers. In one embodiment, the space between adjacent carbon nanotubes along the radial direction of the twisted carbon nanotube wire 15 is less than or equal to 5 nanometers. In one embodiment, the space between adjacent carbon nanotubes along the radial direction of the twisted carbon nanotube wire 15 is less than or equal to 1 nanometer. Since the space between adjacent carbon nanotubes in the radial direction of the twisted carbon nanotube wire 15 is small, and adjacent carbon nanotubes are closely connected by van der Waals force, the twisted carbon nanotube wire 15 includes a smooth and dense surface.
A diameter of the twisted carbon nanotube wire 15 can be set as desired. In one embodiment, the diameter of the twisted carbon nanotube wire 15 ranges from about 1 micron to about 30 microns. A twist of the twisted carbon nanotube wire 15 can range from about 10 r/cm to about 300 r/cm. The twist of the twisted carbon nanotube wire 15 refers to the number of turns per unit length of the twisted carbon nanotube wire 15. When the diameter of the twisted carbon nanotube wire 15 is constant, an appropriate twist can give the twisted carbon nanotube wire 15 excellent mechanical properties. Such as when the diameter of the twisted carbon nanotube wire 15 is less than 10 microns, the twist of the twisted carbon nanotube wire 15 ranges from about 250 r/cm to about 300 r/cm. When the diameter of the twisted carbon nanotube wire 15 ranges from about 10 microns to about 20 microns, the twist of the twisted carbon nanotube wire 15 ranges from about 200 r/cm to about 250 r/cm. When the diameter of the twisted carbon nanotube wire 15 ranges from about 25 microns to about 30 microns, the twist of the twisted carbon nanotube wire 15 ranges from about 100 r/cm to about 150 r/cm. The mechanical strength of the twisted carbon nanotube wire 15 is 5 to 10 times stronger than the mechanical strength of a gold wire of equal diameter.
The carbon nanotube composite wire can be formed by composite of the carbon nanotube wire with metal, polymer, non-metal, or other materials.
The metal layer 16 can improve a conductivity of the shield layer 12, and make the shield layer 12 produce a large induced current when penetrated by a magnetic field. Additionally, the metal layer 16 can improve the corona discharge of the shield layer 12, increase the neutralization of the external charge, and reduce the surface resistivity of the substrate 11. Thus, coating the metal layer 16 on the outer surface of the carbon nanotube wire can improve a radiation efficiency of the shield layer 12.
The metal layer 16 can be formed on the outer surface of the twisted carbon nanotube wire 15 by a method such as plating, electroless plating, or vapor plating. Since the twisted carbon nanotube wire 15 has the smooth and dense surface, the metal layer 16 and the twisted carbon nanotube wire 15 can form a close bond, and the metal layer 16 is not easily detached from the twisted carbon nanotube wire 15. A material of the metal layer 16 can be can be selected from the group consisting of gold, silver, copper, molybdenum, and tungsten, other metals and their alloys having good electrical conductivity. In one embodiment, the diameter of the twisted carbon nanotube wire 15 ranges from about 1 micron to about 30 microns, the thickness of the metal layer 16 ranges from about 1 micron to about 5 microns, and the conductivity of the carbon nanotube composite wire 17 can reach 50 percent or more of the conductivity of the metal layer 16. Experiments show that when the thickness of the metal layer 16 ranges from about 1 micron to about 5 microns, the electrical conductivity of carbon nanotube composite wire 17 can be significantly improved in proportion to an increase of the diameter of the carbon nanotube composite wire 17; and the metal layer 16 is not be easily oxidized, the conductivity and service life of the carbon nanotube composite wire 17 can be increased. In one embodiment, the metal layer 16 is a copper layer, a thickness of the copper layer is about 5 micros; the conductivity of the carbon nanotube composite wire 17 is about 4.39×107S/m, which is about 75% of a conductivity of copper.
When the carbon nanotube structure comprises the carbon nanotube wire and/or the carbon nanotube composite wire 17, the carbon nanotube wire and/or the carbon nanotube composite wire 17 can be braided or twisted together.
The carbon nanotube film can be a drawn carbon nanotube film, a flocculated carbon nanotube film or a pressed carbon nanotube film.
The carbon nanotube composite film can be formed by composite of the carbon nanotube film with metal, polymer, non-metallic or other materials. When the carbon nanotube composite film is formed by composite of the carbon nanotube film with a metal layer, the metal layer can be formed on the outer surface of the carbon nanotube film by a method such as plating, electroless plating, or vapor plating. A material of the metal layer can be selected from the group consisting of gold, silver, copper, and molybdenum tungsten, other metals and their alloys having good electrical conductivity.
The carbon nanotube structure can include at least two stacked carbon nanotube films and/or carbon nanotube composite films. The carbon nanotube structure can also include two or more coplanar carbon nanotube films and/or carbon nanotube composite films.
The electromagnetic shielding material 100 can also include a fabric layer 18. The shield layer 12 can be protected by the fabric layer 18 holding the shield layer 12 together with the substrate 11. A material of the fabric layer 18 can be the same as the material of the substrate 11. The fabric layer 18 is an optional component.
The fabric layer 18 and the shield layer 12 can be sewn together or bonded together with an adhesive.
The metal layer 16 has excellent oxidation resistance and durability due to the thickness of the metal layer ranges from 1 micron to 5 microns, which can improve the durability of the electromagnetic shielding material 100.
Because the thickness of the metal layer 16 ranges from 1 micron to 5 microns, when the carbon nanotube composite wire 17 is used, the metal layer 16 plays a major conductive role; because of a skin effect, the current is mostly transmitted through a surface of the carbon nanotube composite wire 17, that is, current is mostly transmitted under and through the metal layer 16. Thus, the conductivity of the carbon nanotube composite wire 17 is significantly increased, which can improve a work efficiency of the electromagnetic shielding material 100.
The carbon nanotube composite wire 17 has excellent mechanical properties, by optimizing the diameter and the twist of the twisted carbon nanotube wire 15; which can make the electromagnetic shielding material 100 have excellent bend resistance.
When the carbon nanotube composite wire 17 is used, the carbon nanotube wire cannot be easily broken due to the excellent mechanical properties of the carbon nanotube. Thus, the carbon nanotube composite wire 17 can maintain a closed circuit even if the metal layer 16 is broken. A durability of the carbon nanotube composite wire 17 can be improved.
The electromagnetic shielding material 100 can be applied to electromagnetic shielding clothing, such as apron, underwear, shirt, pants, and so on. The electromagnetic shielding clothing can be obtained by cutting out the electromagnetic shielding material 100 directly, or sewing the electromagnetic shielding material 100 between the clothing.
The shield layer of the electromagnetic shielding clothing includes a carbon nanotube structure. The carbon nanotube structure can form a conductive closed circuit due to the excellent conductivity of the carbon nanotubes. When partial carbon nanotubes of the conductive closed circuit cuts magnetic induction lines in a magnetic field, a magnetic flux of the conductive closed circuit will be changed, and an induction electromotive force and an induced current will be produced in the conductive closed circuit, thereby producing a reverse electromagnetic field for shielding the external magnetic field.
The carbon nanotube structure can produce the corona discharge to eliminate external charge. The carbon nanotube structure can also make the electrostatic charge discharge quickly by reducing the surface resistivity of the clothing. Therefore, an anti-radiation and anti-static effect of the clothing can be improved.
The electromagnetic shielding clothing has excellent bend resistance and very little weight due to the excellent mechanical properties and light weight of the carbon nanotube structure.
It is to be understood that the above-described embodiments are intended to illustrate rather than limit the present disclosure. Variations may be made to the embodiments without departing from the spirit of the present disclosure as claimed. Elements associated with any of the above embodiments are envisioned to be associated with any other embodiments. The above-described embodiments illustrate the scope of the present disclosure but do not restrict the scope of the present disclosure.
Number | Date | Country | Kind |
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201420199680.X | Apr 2014 | CN | national |