A liquid-liquid optical fiber based on aerogel hollow fiber, its preparation method and application

Abstract

This invention discloses a liquid-liquid optical fiber based on aerogel hollow fibers, its preparation method, and its applications. The liquid-liquid optical fiber includes a core layer and a sheath covering the core layer. The sheath layer comprises aerogel hollow fibers and a sheath liquid. The sheath liquid impregnates and fills the porous framework of the aerogel hollow fibers to form an aerogel-confined solid-liquid composite hollow fiber. The core layer comprises a core liquid, and the refractive index of the core liquid is greater than that of the sheath liquid. The liquid-liquid optical fiber provided by this invention possesses excellent mechanical properties. The reflective interface of the liquid-liquid optical fiber is a liquid-liquid interface, and the core is a free-flowing liquid. When the liquid optical fiber is bent, the liquid can be transmitted to the surroundings, exhibiting excellent flexibility and resistance to deformation. It can simultaneously achieve reconfigurability of the refraction of the sheath and core layers, and can be applied in fields such as optical transmission, optical communication, optical sensing, illumination, Raman spectroscopy, and nonlinear optics.

Description

Technical Field

[0001] This invention relates to a novel optical fiber technology, specifically to a liquid-liquid optical fiber based on aerogel hollow fiber, its preparation method and application, belonging to the field of nanoporous materials and functional fiber technology. Background Technology

[0002] Optical fiber, short for optical waveguide fiber, is a medium for transmitting optical signals, and its transmission principle is total internal reflection of light. Optical fibers can be divided into communication fibers and functional fibers. Communication fibers are the primary application area of ​​optical waves, while functional fibers can be further divided into power transmission fibers, image transmission fibers, and sensing fibers, representing a promising field for development. Due to its advantages such as long transmission distance, strong anti-interference capability, large bandwidth, good stability, and high security, optical fiber technology has become the core technology dominating global communication networks. In addition, the continuous development of optical fiber technology has brought tremendous changes to fields such as medical treatment, medical devices, and sensing. Traditional optical fibers are made from glass or polymers, and the interface for achieving total internal reflection is generally a solid-solid interface. Due to their high rigidity, it is difficult to achieve bending with a small radius of curvature, resulting in poor flexibility and limited braiding ability. The high modulus also limits the feasibility of optical fibers in emerging and diversified application areas, such as flexible wearables, smart fabrics, and portable functional devices / equipment.

[0003] In recent years, hydrogels have been used by researchers to prepare hydrogel optical fibers due to their excellent flexibility and biocompatibility. Patent CN110541209A invented a continuous preparation method for hydrogel optical fibers based on reactive spinning, including: a skin spinning solution and a core spinning solution, using a transverse coaxial needle as the spinning nozzle, using CaCl2 aqueous solution as a coagulation bath to solidify sodium alginate in the skin layer, and using an ultraviolet light source to initiate the free radical polymerization reaction of PEGDA in the core spinning solution; after stretching, a skin-core structure hydrogel optical fiber with good biocompatibility is finally obtained. The following problems exist with hydrogel optical fibers as described above: (1) Hydrogel optical fibers are prone to swelling and are easily affected by permeable substances, resulting in unstable optical waveguide performance, which in turn affects their light transmission and sensing capabilities; (2) Due to the monomer polymerization process, defects such as molecular chain entanglement and non-uniform pore structure are easily caused, making the preparation of high-transmittance hydrogel materials more difficult; (3) The fixed nature of the optical guide path limits the introduction of functional phases; (4) The refractive index difference between the inner and outer layers is relatively small, resulting in a relatively small numerical aperture, which leads to a relatively weak ability of the optical fiber to receive light. Patent CN109898176A invented a flexible and stretchable hydrogel optical fiber, wherein the optical fiber has a core-sheath structure, wherein the sheath is a transparent silicone capillary and the core is a polyacrylamide hydrogel containing lithium bromide. Although the hydrogel optical fiber prepared by this patent has the characteristics of flexibility, stretchability and stable signal transmission, the modulus of the cladding silicone is much greater than that of the hydrogel, which will cause the material to generate internal stress when subjected to force, thereby affecting the overall performance and reliability of the optical fiber.

[0004] Liquid-core fiber differs from common silica fiber. It consists of a highly transparent flexible polymer as the cladding tube, a transparent liquid with a refractive index greater than the cladding as the core, and a rigid material as the transparent optical window. Light is transmitted through total internal reflection within the core. The liquid-core fiber core is filled with liquid, giving it advantages unmatched by silica, plastic, and hydrogel fibers. For example, the free-flowing liquid inside the core allows for the release of internal stress when the fiber is bent, enabling a larger bending radius and increased usability, avoiding damage easily caused by bending in traditional silica fibers. Furthermore, the core liquid can be replaced as needed to obtain different aperture values, meeting various practical requirements. The numerical aperture can be made higher, improving optical energy utilization. Patent CN109946788A proposes a reconfigurable liquid-core fiber capable of outputting lasers of different wavelengths, thereby improving the applicability of lasers. This reconfigurable liquid-core fiber includes a first sub-fiber, a second sub-fiber, and a third sub-fiber connected sequentially. The second sub-fiber includes a second core, which is hollow. The first and third sub-fibers together form a resonant cavity in the second sub-fiber. A liquid flow channel is provided on the second sub-fiber, communicating with the second core. This liquid flow channel is used to inject and discharge liquid dye into the second core, thus forming the reconfigurable liquid-core fiber. Another patent, CN114163676A, provides a liquid-core hydrogel fiber, comprising a hollow hydrogel core, a liquid core within the hollow hydrogel core, and a hydrogel cladding covering the surface of the hollow hydrogel core. This liquid-core hydrogel fiber combines the advantages of hydrogel fibers and liquid-core fibers, exhibiting high optical transmission efficiency, good flexibility, and wide applicability. However, inevitably, due to its hydrogel cladding, this liquid-core hydrogel fiber is prone to swelling, which affects the total internal reflection interface and thus the optical transmission performance. Secondly, the cladding material is fixed as a hydrogel material, and the cladding material cannot be changed in a timely manner according to actual needs. Thirdly, since both the light-transmitting liquid core and the sensing liquid core are dissolved in water, the liquid core material easily diffuses into the cladding hydrogel, resulting in no obvious total internal reflection interface between the cladding and the fiber core, which leads to severe optical loss and poor light transmission stability.

[0005] Aerogel materials are a novel type of lightweight, porous synthetic material. Their preparation typically involves supercritical drying or freeze-drying to replace the liquid in the wet gel with gas, without significantly altering the gel's network structure. This results in unique properties such as extremely low apparent density and thermal conductivity, high porosity, and specific surface area. Aerogel fibers retain the aerogel characteristics while also possessing the properties of fine, long fibers, which will further broaden the application areas of aerogel materials. Compared to hydrogel fibers, aerogel fibers have a robust network framework structure that does not swell in water, and based on their mesoporous nanoconfining effect, aerogel fibers can effectively confine various functional liquids.

[0006] In summary, there is currently no optical fiber based on aerogel materials, and developing aerogel-based optical fiber technology presents unparalleled challenges. No optical fiber can currently achieve reconfigurability of the refractive index of both the skin and core layers. Summary of the Invention

[0007] The main objective of this invention is to provide a liquid-liquid optical fiber based on aerogel hollow fiber and its preparation method, so as to overcome the shortcomings of the prior art.

[0008] Another object of the present invention is to provide the application of the aforementioned liquid-liquid optical fiber based on aerogel hollow fiber.

[0009] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0010] This invention provides a liquid-liquid optical fiber based on aerogel hollow fiber, comprising a core layer and a sheath covering the core layer. The sheath comprises aerogel hollow fiber and a sheath liquid. The sheath liquid impregnates and fills the porous skeleton of the aerogel hollow fiber to form an aerogel-confined solid-liquid composite hollow fiber. The core layer comprises a core liquid, and the refractive index of the core liquid is greater than that of the sheath liquid.

[0011] This invention also provides a method for fabricating a liquid-liquid optical fiber based on aerogel hollow fibers, comprising:

[0012] Preparation of aerogel hollow fibers;

[0013] The aerogel hollow fiber is impregnated with a skin liquid and filled into the porous skeleton of the aerogel hollow fiber to obtain aerogel-confined solid-liquid composite hollow fiber, which serves as the skin layer.

[0014] A core layer liquid is filled inside the solid-liquid composite hollow fiber to form a core layer, thereby obtaining a liquid-liquid optical fiber based on aerogel hollow fiber, wherein the refractive index of the core layer liquid is greater than that of the skin layer liquid.

[0015] This invention also provides a liquid-liquid optical fiber based on aerogel hollow fiber prepared by the aforementioned method.

[0016] This invention also provides applications of the liquid-liquid optical fiber based on aerogel hollow fiber in fields such as optical transmission, optical communication, optical sensing, illumination, Raman spectroscopy, or nonlinear optics.

[0017] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0018] 1) The liquid-liquid optical fiber based on aerogel hollow fiber provided by the present invention has a wide range of selectable liquids for the sheath and core, and can obtain optical fibers with large numerical aperture; the liquid-liquid optical fiber has excellent mechanical properties, the reflective interface of the liquid-liquid optical fiber is a liquid-liquid interface and the core is a free-flowing liquid, when the liquid optical fiber is bent, the liquid can be transmitted to the surroundings, and it has excellent flexibility and resistance to deformation.

[0019] 2) Compared with hydrogel optical fiber, the liquid-liquid optical fiber based on aerogel hollow fiber provided by the present invention has a robust network skeleton structure that does not swell when exposed to water. Based on its mesoporous nano-confining effect, the skin can not only confine water, but also confine various functional liquids well, thereby endowing the liquid-liquid optical fiber with various functions.

[0020] 3) Compared with commercial liquid-core optical fiber, the liquid-liquid optical fiber based on aerogel hollow fiber provided by the present invention can achieve reconfigurability not only in the core liquid, but also in the skin by wetting different kinds of liquid. The liquid-liquid optical fiber can simultaneously achieve reconfigurability of refraction in both the skin and the core.

[0021] 4) The liquid-liquid optical fiber based on aerogel hollow fiber provided by this invention is a novel type of optical fiber, which fills the gap in aerogel-based optical fiber materials and promotes the application of optical fiber in fields such as optical transmission, optical communication, optical sensing, lighting, Raman spectroscopy and nonlinear optics, especially in underwater environments such as underwater optical communication, underwater optical sensing and underwater optical fiber lighting. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure and light transmission of a liquid-liquid optical fiber based on aerogel hollow fiber in a typical embodiment of the present invention.

[0024] Figure 2 These are scanning electron microscope images of the aerogel hollow fibers obtained in Example 1 of this invention;

[0025] Figure 3 This is a schematic diagram of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in Embodiment 1 of the present invention for laser waveguides of different wavelengths.

[0026] Figure 4 These are comparison photos of the diameter of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in Example 2 of this invention before and after immersion in pure water for 2 days;

[0027] Figure 5 This is a stretching curve of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in Embodiment 2 of the present invention;

[0028] Figure 6 These are digital photographs of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in Embodiment 2 of the present invention under different bending angles. Detailed Implementation

[0029] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention, which mainly provides a liquid-liquid optical fiber based on aerogel hollow fiber, its preparation method and application, filling the gap in optical fiber technology based on aerogel materials. It aims to solve the thorny problems in the prior art, such as the easy swelling of hydrogel optical fibers and the inability to simultaneously reconstruct the refractive index of the skin and core layers. The following will further explain the technical solution, its implementation process and principles.

[0030] As one aspect of the technical solution of the present invention, a liquid-liquid optical fiber based on aerogel hollow fiber includes a core layer and a skin layer covering the core layer. The skin layer includes aerogel hollow fiber and skin liquid. The skin liquid impregnates and fills the porous skeleton of the aerogel hollow fiber to form an aerogel-confined solid-liquid composite hollow fiber. The core layer includes core liquid.

[0031] In some implementations, the core liquid and the skin liquid are immiscible and exist stably together.

[0032] In some embodiments, the refractive index of the core liquid is greater than that of the skin liquid.

[0033] Furthermore, the difference between the refractive index of the core liquid and the refractive index of the skin liquid is 0.0001~1.

[0034] In some embodiments, the skin liquid may include any one or a combination of two or more of the following: pure water, aqueous solutions, aqueous emulsions, aromatic hydrocarbon organic solvents, aliphatic hydrocarbon organic solvents, alicyclic hydrocarbon organic solvents, halogenated hydrocarbon organic solvents, alcohol organic solvents, ether organic solvents, ester organic solvents, ketone organic solvents, glycol derivative organic solvents, oil liquids, acetonitrile, pyridine, phenol, carbon disulfide, etc., but is not limited thereto.

[0035] In some embodiments, the core liquid may include any one or a combination of two or more of the following: pure water, aqueous solution, aqueous emulsion, aromatic hydrocarbon organic solvent, aliphatic hydrocarbon organic solvent, alicyclic hydrocarbon organic solvent, halogenated hydrocarbon organic solvent, alcohol organic solvent, ether organic solvent, ester organic solvent, ketone organic solvent, glycol derivative organic solvent, oil liquid, acetonitrile, pyridine, phenol, carbon disulfide, etc., but is not limited thereto.

[0036] Furthermore, the aforementioned aromatic hydrocarbon organic solvents may include any one or a combination of two or more of benzene, toluene, xylene, nitrobenzene, etc., but are not limited to these.

[0037] Furthermore, the aliphatic hydrocarbon organic solvent may include any one or a combination of two or more of pentane, hexane, octane, tetradecane, hexadecane, etc., but is not limited to this.

[0038] Furthermore, the alicyclic hydrocarbon organic solvent may include any one or a combination of two or more of cyclohexane, cyclohexanone, toluenecyclohexanone, etc., but is not limited to this.

[0039] Furthermore, the halogenated hydrocarbon organic solvent may include any one or a combination of two or more of chlorobenzene, dichlorobenzene, dichloromethane, trichloromethane, tetrachloroethylene, etc., but is not limited to this.

[0040] Furthermore, the alcoholic organic solvent may include any one or a combination of two or more of methanol, ethanol, isopropanol, etc., but is not limited to this.

[0041] Furthermore, the ether-based organic solvent may include any one or a combination of two of petroleum ether, propylene oxide, etc., but is not limited to this.

[0042] Furthermore, the ester organic solvent includes any one or a combination of two or more of methyl acetate, ethyl acetate, propyl acetate, etc., but is not limited to these.

[0043] Furthermore, the ketone organic solvent includes any one or a combination of two or more of acetone, methyl ethyl ketone, methyl isobutyl ketone, etc., but is not limited to these.

[0044] Furthermore, the diol derivative organic solvent includes any one or a combination of two or more of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether, but is not limited thereto.

[0045] Furthermore, the oily liquid includes any one or a combination of two or more of gasoline, silicone oil, kerosene, mineral oil, oleic acid, perfluoropolyether oil, etc., but is not limited to these.

[0046] In some embodiments, the aerogel hollow fiber includes any one or a combination of two or more of organic aerogel hollow fibers, inorganic aerogel hollow fibers, organic-inorganic hybrid aerogel hollow fibers, etc., but is not limited thereto.

[0047] In some preferred embodiments, the organic aerogel hollow fiber may include any one or a combination of two or more of the following: aromatic polyamide aerogel hollow fiber, cellulose aerogel hollow fiber, sodium alginate aerogel hollow fiber, chitosan aerogel hollow fiber, polyvinyl alcohol aerogel hollow fiber, silk fibroin aerogel hollow fiber, polyimide aerogel hollow fiber, polyurethane aerogel hollow fiber, polyurea aerogel hollow fiber, phenolic aerogel hollow fiber, polyamide aerogel hollow fiber, polyester aerogel hollow fiber, polyethylene aerogel hollow fiber, polystyrene aerogel hollow fiber, polypyrrole aerogel hollow fiber, and polyvinylidene chloride aerogel hollow fiber, but is not limited thereto.

[0048] In some preferred embodiments, the inorganic aerogel hollow fiber may include any one or a combination of two or more of the following: silica aerogel hollow fiber, titanium dioxide aerogel hollow fiber, alumina aerogel hollow fiber, zirconium oxide aerogel hollow fiber, graphene aerogel hollow fiber, carbon nanotube aerogel hollow fiber, metal aerogel hollow fiber, carbide aerogel hollow fiber, nitride aerogel hollow fiber, etc., but is not limited thereto.

[0049] In some preferred embodiments, the organic-inorganic hybrid aerogel hollow fiber is made from the aforementioned organic aerogel hollow fiber and inorganic aerogel hollow fiber.

[0050] In some embodiments, the aerogel-based hollow fiber liquid-liquid optical fiber has a liquid-liquid-based soft interface, thereby exhibiting excellent flexibility.

[0051] Furthermore, the liquid-liquid optical fiber based on aerogel hollow fiber can achieve total internal reflection of light at an interface with molecular-level roughness.

[0052] In some embodiments, the liquid-liquid optical fiber based on aerogel hollow fiber has a tensile strength of 0.1~100MPa, a breaking elongation of 5%~1000%, and a bending stiffness of 0.1~10000E. -10 N m 2 The minimum bending radius is 0.01~1000mm.

[0053] In some embodiments, the outer diameter of the liquid-liquid optical fiber based on aerogel hollow fiber is 0.01~100 mm, preferably 0.01~20 mm, and the inner diameter (light transmission diameter) is 0.01~100 mm, preferably 0.01~20 mm.

[0054] In some embodiments, the cladding thickness of the aerogel-based hollow fiber liquid-liquid optical fiber is 0.01~100 mm, preferably 0.01~20 mm.

[0055] In some embodiments, the numerical aperture of the liquid-liquid optical fiber based on aerogel hollow fiber is 0.1~1.5, preferably 0.1~1, the wavelength range of transmitted light is 0.01~100 μm, the light transmittance is 1%~100%, and the light attenuation coefficient is 0.001~100 dB / cm.

[0056] Furthermore, the structural schematic diagram and light transmission schematic diagram of the liquid-liquid optical fiber based on aerogel hollow fiber are as follows: Figure 1 As shown, specifically: the light transmission principle is the phenomenon of total internal reflection. When light rays travel from the high-refractive-index core to the low-refractive-index cladding, if the angle of incidence is greater than or equal to the critical angle of total internal reflection, the light rays will no longer refract but will be completely reflected back to the core. This phenomenon is called total internal reflection. In liquid-liquid optical fibers based on aerogel hollow fibers, n2 > n1 > n0. Due to the effect of total internal reflection, light rays can be continuously reflected forward in the core layer of the liquid-liquid optical fiber based on aerogel hollow fibers, thereby realizing the transmission of light. Here, n0 is the air refractive index, n1 is the cladding refractive index, and n2 is the core liquid refractive index.

[0057] Furthermore, compared with ordinary quartz glass optical fiber, it has a wider wavelength range for transmitting light. Quartz optical fiber absorbs light in the ultraviolet region below 300 nm, resulting in high light loss and making it unsuitable for ultraviolet light transmission. Fields such as ultraviolet curing and fluorescence detection require optical fibers that can transmit ultraviolet light.

[0058] Furthermore, compared with plastic optical fiber, quartz optical fiber, and hydrogel optical fiber, it has a larger numerical aperture. Generally, the difference in refractive index between the core and cladding of optical fiber is very small, resulting in a small numerical aperture. However, the liquid-liquid optical fiber of the present invention has a wide range of selectable liquids in the core and cladding, which can obtain optical fibers with a large numerical aperture.

[0059] Furthermore, compared with plastic optical fiber, quartz optical fiber, and hydrogel optical fiber, the liquid-liquid optical fiber of the present invention has excellent mechanical properties. The reflective interface of the liquid-liquid optical fiber is a liquid-liquid interface and the core is a free-flowing liquid. When the liquid optical fiber is bent, the liquid can be transmitted to the surroundings, exhibiting excellent flexibility and resistance to deformation.

[0060] Furthermore, compared with hydrogel optical fibers, the liquid-liquid optical fiber of the present invention has a robust network skeleton structure based on an aerogel skin that does not swell when exposed to water. Moreover, based on the nano-confining effect of its mesopores, the skin can not only confine water, but also confine various functional liquids well, thereby endowing the liquid-liquid optical fiber with various functionalities.

[0061] Furthermore, compared to commercial liquid-core optical fibers, liquid-liquid optical fibers not only achieve reconfigurability in the core liquid, but also in the skin by wetting different liquids. Liquid-liquid optical fibers can simultaneously achieve reconfigurability of refraction in both the skin and the core.

[0062] Specifically, as another aspect of the technical solution of this invention, a method for preparing a liquid-liquid optical fiber based on aerogel hollow fiber includes:

[0063] Preparation of aerogel hollow fibers;

[0064] The aerogel hollow fiber is impregnated with a skin liquid and filled into the porous skeleton of the aerogel hollow fiber to obtain aerogel-confined solid-liquid composite hollow fiber, which serves as the skin layer.

[0065] A core layer liquid is filled inside the solid-liquid composite hollow fiber to form a core layer, thereby obtaining a liquid-liquid optical fiber based on aerogel hollow fiber, wherein the refractive index of the core layer liquid is greater than that of the skin layer liquid.

[0066] The preparation method provided by this invention mainly uses aerogel hollow fiber as a model. Based on the nano-confinement effect of aerogel on liquid, two immiscible liquids with different refractive indices (the refractive index of the core liquid is greater than that of the skin liquid) are filled into the skin and core of the aerogel fiber to form a liquid-liquid interface to achieve total internal reflection of light and thus realize an optical waveguide.

[0067] In some embodiments, the preparation method includes: preparing aerogel hollow fibers from a spinning solution by spinning technology and drying treatment.

[0068] In some preferred embodiments, the spinning solution may include any one or more combinations of aromatic polyamide molecular solutions, aromatic polyamide nanofiber solutions, cellulose solutions, cellulose nanofiber dispersions, sodium alginate solutions, chitosan solutions, polyvinyl alcohol solutions, silk fibroin solutions, polyimide precursor solutions, polyurethane solutions, phenolic precursor solutions, polyurea precursor solutions, polyamide precursor solutions, polyester precursor solutions, polyethylene precursor solutions, polystyrene precursor solutions, polypyrrole gas precursor solutions, polyvinylidene chloride precursor solutions, silica sol, titanium dioxide precursor solutions, alumina precursor solutions, zirconium oxide precursor solutions, graphene dispersions, carbon nanotube dispersions, metal precursor solutions, carbide precursor solutions, and nitride precursor solutions, but is not limited thereto.

[0069] In some preferred embodiments, the spinning technology includes, but is not limited to, the formation of filaments using a hollow spinneret or coaxial needle through any one or a combination of two or more of the following methods: gel spinning, wet spinning, dry spinning, dry-jet wet spinning, dry cryogenic spinning, 3D printing, and mold-based filament formation.

[0070] In some preferred embodiments, the drying process may include any one or a combination of two or more of the following: supercritical fluid drying, vacuum freeze drying, reduced pressure drying, and atmospheric pressure drying, but is not limited thereto.

[0071] In some implementations, the immersion time is 1 min to 48 h.

[0072] In some embodiments, the preparation method includes: filling the core layer of the solid-liquid composite hollow fiber with core layer liquid by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0073] In some implementations, the core liquid and skin liquid used in this preparation method are as defined above.

[0074] In some specific implementations, the skin liquid includes pure water; aqueous solutions; aqueous emulsions; aromatic hydrocarbon organic solvents such as benzene, toluene, xylene, and nitrobenzene; aliphatic hydrocarbon organic solvents such as pentane, hexane, octane, tetradecane, and hexadecane; alicyclic hydrocarbon organic solvents such as cyclohexane, cyclohexanone, and toluenecyclohexanone; halogenated hydrocarbon organic solvents such as chlorobenzene, dichlorobenzene, dichloromethane, trichloromethane, and tetrachloroethylene; and alcohol organic solvents such as methanol, ethanol, and isopropanol. Ethers such as petroleum ether and propylene oxide; esters such as methyl acetate, ethyl acetate, and propyl acetate; ketones such as acetone, methyl butyl ketone, and methyl isobutyl ketone; glycol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether; organic solvents such as acetonitrile, pyridine, phenol, and carbon disulfide; oils such as gasoline, silicone oil, kerosene, mineral oil, oleic acid, and perfluoropolyether oil; any one or more combinations of the above liquids, but not limited to these.

[0075] In some specific implementations, the core layer liquid includes pure water; aqueous solutions; aqueous emulsions; aromatic hydrocarbon organic solvents such as benzene, toluene, xylene, and nitrobenzene; aliphatic hydrocarbon organic solvents such as pentane, hexane, octane, tetradecane, and hexadecane; alicyclic hydrocarbon organic solvents such as cyclohexane, cyclohexanone, and toluenecyclohexanone; halogenated hydrocarbon organic solvents such as chlorobenzene, dichlorobenzene, dichloromethane, trichloromethane, and tetrachloroethylene; and alcohol organic solvents such as methanol, ethanol, and isopropanol. Ethers such as petroleum ether and propylene oxide; esters such as methyl acetate, ethyl acetate, and propyl acetate; ketones such as acetone, methyl butyl ketone, and methyl isobutyl ketone; glycol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether; organic solvents such as acetonitrile, pyridine, phenol, and carbon disulfide; oils such as gasoline, silicone oil, kerosene, mineral oil, oleic acid, and perfluoropolyether oil; any one or more combinations of the above liquids, but not limited to these.

[0076] In some more specific embodiments, the method for fabricating the liquid-liquid optical fiber based on aerogel hollow fiber includes the following steps:

[0077] (1) Aerogel hollow fibers were prepared by using coaxial spinning and drying techniques on the spinning solution;

[0078] (2) Select a cortex liquid to impregnate the aerogel hollow fiber and fill the porous skeleton of the aerogel hollow fiber to obtain aerogel-confined solid-liquid composite hollow fiber.

[0079] (3) The core liquid is filled into the core layer of the solid-liquid composite hollow fiber by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0080] In summary, the preparation method of the present invention is simple to operate, has a short preparation cycle, low production cost, is easy to mass-produce, and does not require expensive instruments such as fiber optic fusion splicers.

[0081] As another aspect of the technical solution of the present invention, it also relates to a liquid-liquid optical fiber based on aerogel hollow fiber prepared by the aforementioned preparation method.

[0082] Another aspect of the present invention provides the aforementioned application of liquid-liquid optical fibers based on aerogel hollow fibers.

[0083] The liquid-liquid optical fiber based on aerogel hollow fiber provided by this invention is a novel type of optical fiber that fills the gap in aerogel-based optical fiber materials. The liquid-liquid optical fiber has optical waveguide properties, which promotes its application in fields such as optical transmission, optical communication, optical sensing, lighting, Raman spectroscopy and nonlinear optics, especially in underwater environments such as underwater optical communication, underwater optical sensing and underwater fiber optic lighting.

[0084] In summary, compared to previous optical fiber fabrication methods, the liquid-liquid optical fiber fabrication method based on aerogel hollow fibers provided by this invention has the advantages of being simple and easy to operate and not requiring expensive equipment (such as optical fiber fusion splicers). The resulting liquid-liquid optical fiber has characteristics such as large core diameter, large numerical aperture, wide spectral transmission range, high light transmission efficiency, and good bending performance. The resulting liquid-liquid optical fiber can be used in optical transmission, optical communication, optical sensing, lighting, Raman spectroscopy, and nonlinear optics, especially in underwater environments such as underwater optical communication, underwater optical sensing, and underwater fiber optic lighting.

[0085] The technical solutions of the present invention are further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention. Those skilled in the art can make adjustments according to actual circumstances. The implementation conditions used in the following embodiments can be further adjusted according to actual needs, and the implementation conditions not specified are generally the conditions in conventional experiments.

[0086] Example 1

[0087] (1) Hollow aromatic polyamide wet gel fibers were obtained by coaxial wet spinning of aromatic polyamide nanofiber dispersion, and aromatic polyamide aerogel hollow fibers were obtained by supercritical drying of hollow aromatic polyamide wet gel fibers.

[0088] (2) The aromatic polyamide aerogel hollow fiber obtained in step (1) is fully soaked in deionized water for 12 hours to obtain aerogel-confined solid-liquid composite hollow fiber.

[0089] (3) Silicone oil is filled into the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0090] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.404, a skin refractive index of 1.336, a numerical aperture of 0.432, an optical attenuation coefficient of 0.3 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light transmission diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a tensile strength of 2 MPa, a tensile elongation at break of 25%, and a bending stiffness of 12 E. -10 N m 2 The minimum bending radius is 1.0 mm.

[0091] The scanning electron microscope (SEM) image of the aerogel hollow fiber obtained in this embodiment after the above steps is shown below. Figure 2 As shown in the figure, the schematic diagram of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment for laser waveguides of different wavelengths is as follows. Figure 3 As shown.

[0092] Example 2

[0093] (1) Hollow aromatic polyamide wet gel fibers were obtained by coaxial wet spinning of aromatic polyamide nanofiber dispersion, and aromatic polyamide aerogel hollow fibers were obtained by supercritical drying of hollow aromatic polyamide wet gel fibers.

[0094] (2) The aromatic polyamide aerogel hollow fiber obtained in step (1) is fully soaked in deionized water for 24 hours to obtain aerogel-confined solid-liquid composite hollow fiber.

[0095] (3) By pressure injection, tetradecane is filled into the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0096] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.429, a skin refractive index of 1.336, a numerical aperture of 0.507, an optical attenuation coefficient of 0.5 dB / cm, an outer diameter of 1.2 mm, an inner diameter (light transmission diameter) of 0.9 mm, an aerogel skin thickness of 0.15 mm, a tensile strength of 8 MPa, a tensile elongation at break of 40%, and a bending stiffness of 120 E. -10 N m 2 The minimum bending radius is 0.7 mm.

[0097] Following the above steps, the diameter comparison of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment before and after immersion in pure water for 2 days is as follows: Figure 4 As shown, the liquid-liquid optical fiber based on aerogel hollow fiber does not swell in water; the tensile curve of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment is shown in the figure. Figure 5 As shown; digital photographs of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment under different bending angles are shown below. Figure 6 As shown.

[0098] Example 3

[0099] (1) Aromatic polyamide molecular solution is coaxially spun through a hollow spinneret to obtain hollow aromatic polyamide wet gel fiber, and the hollow aromatic polyamide wet gel fiber is freeze-dried under vacuum to obtain aromatic polyamide aerogel hollow fiber.

[0100] (2) The aromatic polyamide aerogel hollow fiber obtained in step (1) is fully soaked in deionized water for 5 minutes to obtain aerogel-confined solid-liquid composite hollow fiber.

[0101] (3) Nitrobenzene is filled into the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0102] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.552, a skin refractive index of 1.336, a numerical aperture of 0.789, an optical attenuation coefficient of 0.2 dB / cm, an outer diameter of 0.01 mm, an inner diameter (light transmission diameter) of 0.004 mm, an aerogel skin thickness of 0.003 mm, a tensile strength of 32 MPa, a tensile elongation at break of 120%, and a bending stiffness of 60 E. -10 N m 2 The minimum bending radius is 0.6 mm.

[0103] Example 4

[0104] (1) Hollow cellulose wet gel fibers were obtained by coaxial wet spinning of cellulose nanofiber dispersion, and cellulose aerogel hollow fibers were obtained by vacuum drying of hollow cellulose wet gel fibers.

[0105] (2) The cellulose aerogel hollow fiber obtained in step (1) is fully immersed in perfluoropolyether oil for 1 min to obtain aerogel-confined solid-liquid composite hollow fiber.

[0106] (3) Cyclohexane is filled into the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0107] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.426, a skin refractive index of 1.300, a numerical aperture of 0.586, an optical attenuation coefficient of 0.8 dB / cm, an outer diameter of 3 mm, an inner diameter (light transmission diameter) of 2 mm, an aerogel skin thickness of 0.5 mm, a tensile strength of 4 MPa, an elongation at break of 500%, and a bending stiffness of 0.3 E. -10 N m 2 The minimum bending radius is 0.1 mm.

[0108] Example 5

[0109] (1) Hollow sodium alginate wet gel fibers were obtained by coaxial wet spinning of sodium alginate solution, and sodium alginate aerogel hollow fibers were obtained by supercritical drying of the hollow sodium alginate wet gel fibers.

[0110] (2) The sodium alginate aerogel hollow fiber obtained in step (1) is fully soaked in calcium chloride solution for 24 hours to obtain aerogel-confined solid-liquid composite hollow fiber.

[0111] (3) By pressure injection, chloroform is filled into the core layer of the solid-liquid composite hollow fiber confined by aerogel obtained in step (2) to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0112] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.447, a skin refractive index of 1.350, a numerical aperture of 0.520, an optical attenuation coefficient of 0.2 dB / cm, an outer diameter of 0.8 mm, an inner diameter (light transmission diameter) of 0.4 mm, an aerogel skin thickness of 0.2 mm, a tensile strength of 30 MPa, a tensile elongation at break of 1000%, and a bending stiffness of 20 E. -10 N m 2 The minimum bending radius is 0.4 mm.

[0113] Example 6

[0114] (1) Hollow chitosan wet gel fibers were obtained by coaxial 3D printing of chitosan solution, and chitosan aerogel hollow fibers were obtained by supercritical drying of the hollow chitosan wet gel fibers.

[0115] (2) The chitosan aerogel hollow fiber obtained in step (1) is fully soaked in perfluoropolyether oil for 36 hours to obtain aerogel-confined solid-liquid composite hollow fiber.

[0116] (3) Carbon disulfide is filled into the core layer of the solid-liquid composite hollow fiber confined by aerogel obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0117] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.628, a skin refractive index of 1.300, a numerical aperture of 0.980, an optical attenuation coefficient of 0.01 dB / cm, an outer diameter of 1.5 mm, an inner diameter (light transmission diameter) of 0.5 mm, a thickness of 0.5 mm for the aerogel skin, a tensile strength of 25 MPa, a breaking elongation of 90%, and a bending stiffness of 100 E. -10 N m 2 The minimum bending radius is 0.2 mm.

[0118] Example 7

[0119] (1) Hollow polyvinyl alcohol wet gel fibers are obtained by coaxial dry-spraying wet spinning of polyvinyl alcohol solution, and polyvinyl alcohol aerogel hollow fibers are obtained by supercritical drying of hollow polyvinyl alcohol wet gel fibers.

[0120] (2) The polyvinyl alcohol aerogel hollow fiber obtained in step (1) is fully soaked in boric acid aqueous solution for 48 hours to obtain aerogel-confined solid-liquid composite hollow fiber.

[0121] (3) By pressure injection, tetrachloroethylene is filled into the core layer of the solid-liquid composite hollow fiber confined by aerogel obtained in step (2) to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0122] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.505, a skin refractive index of 1.385, a numerical aperture of 0.588, an optical attenuation coefficient of 5.0 dB / cm, an outer diameter of 5.0 mm, an inner diameter (light transmission diameter) of 3.0 mm, an aerogel skin thickness of 1.0 mm, a tensile strength of 6 MPa, a tensile elongation at break of 50%, and a bending stiffness of 15 E. -10 N m 2 The minimum bending radius is 0.5 mm.

[0123] Example 8

[0124] (1) Hollow silica wet gel fibers were obtained by coaxial wet spinning of silica sol solution, and silica aerogel hollow fibers were obtained by supercritical drying.

[0125] (2) The silica aerogel hollow fiber obtained in step (1) is fully soaked in perfluoropolyether oil for 12 hours to obtain aerogel-confined solid-liquid composite hollow fiber.

[0126] (3) Silicone oil is filled into the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0127] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.710, a skin refractive index of 1.290, a numerical aperture of 1.12, an optical attenuation coefficient of 0.001 dB / cm, an outer diameter of 0.9 mm, an inner diameter (light transmission diameter) of 0.5 mm, a aerogel skin thickness of 0.2 mm, a tensile strength of 0.1 MPa, a breaking elongation of 5%, and a bending stiffness of 10000 E. -10 N m 2 The minimum bending radius is 1000 mm.

[0128] Example 9

[0129] (1) Hollow polyimide wet gel fibers are obtained by forming polyimide precursor solution into fibers through a mold, and polyimide aerogel hollow fibers are obtained by supercritical drying of hollow polyimide wet gel fibers.

[0130] (2) The polyimide aerogel hollow fiber obtained in step (1) is fully soaked in silicone oil for 6 hours to obtain aerogel-confined solid-liquid composite hollow fiber.

[0131] (3) Oleic acid is filled into the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0132] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.463, a skin refractive index of 1.392, a numerical aperture of 0.450, an optical attenuation coefficient of 100 dB / cm, an outer diameter of 1 mm, an inner diameter (light transmission diameter) of 0.8 mm, an aerogel skin thickness of 0.1 mm, a tensile strength of 100 MPa, an elongation at break of 100%, and a bending stiffness of 0.1 E. -10 N m 2 The minimum bending radius is 0.01 mm.

[0133] Example 10

[0134] (1) Hollow aromatic polyamide wet gel fibers were obtained by coaxial wet spinning of aromatic polyamide nanofiber dispersion, and aromatic polyamide aerogel hollow fibers were obtained by supercritical drying of hollow aromatic polyamide wet gel fibers.

[0135] (2) The aromatic polyamide aerogel hollow fiber obtained in step (1) is fully soaked in perfluorinated polyether oil for 20 hours to obtain aerogel-confined solid-liquid composite hollow fiber.

[0136] (3) Kerosene is filled into the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0137] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.328, a skin refractive index of 1.300, a numerical aperture of 0.271, an optical attenuation coefficient of 1.1 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light transmission diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a tensile strength of 1.8 MPa, a breaking elongation of 26%, and a bending stiffness of 30 E. -10 N m 2 The minimum bending radius is 1.0 mm.

[0138] Example 11

[0139] (1) Hollow aromatic polyamide wet gel fibers were obtained by coaxial wet spinning of aromatic polyamide nanofiber dispersion, and aromatic polyamide aerogel hollow fibers were obtained by supercritical drying of hollow aromatic polyamide wet gel fibers.

[0140] (2) The aromatic polyamide aerogel hollow fiber obtained in step (1) is fully immersed in acetonitrile for 30 hours to obtain aerogel-confined solid-liquid composite hollow fiber.

[0141] (3) By pressure injection, n-hexane is filled into the core layer of the solid-liquid composite hollow fiber confined by aerogel obtained in step (2) to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0142] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.375, a skin refractive index of 1.350, a numerical aperture of 0.261, an optical attenuation coefficient of 0.8 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light transmission diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a tensile strength of 1.7 MPa, a breaking elongation of 19%, and a bending stiffness of 9 E. -10 N m 2The minimum bending radius is 0.9 mm.

[0143] Example 12

[0144] (1) Hollow aromatic polyamide wet gel fibers were obtained by coaxial wet spinning of aromatic polyamide nanofiber dispersion, and aromatic polyamide aerogel hollow fibers were obtained by supercritical drying of hollow aromatic polyamide wet gel fibers.

[0145] (2) The aromatic polyamide aerogel hollow fiber obtained in step (1) is fully soaked in ethanol for 30 min to obtain aerogel-confined solid-liquid composite hollow fiber.

[0146] (3) Petroleum ether is filled into the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0147] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.428, a skin refractive index of 1.370, a numerical aperture of 0.403, an optical attenuation coefficient of 0.4 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light transmission diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a tensile strength of 2.5 MPa, a breaking elongation of 34%, and a bending stiffness of 30 E. -10 N m 2 The minimum bending radius is 0.5 mm.

[0148] Example 13

[0149] (1) Hollow graphene wet gel fibers were obtained by coaxial wet spinning of graphene dispersion, and graphene aerogel hollow fibers were obtained by supercritical drying of hollow graphene wet gel fibers.

[0150] (2) The graphene aerogel hollow fiber obtained in step (1) is fully soaked in silicone oil for 3 h to obtain aerogel-confined solid-liquid composite hollow fiber.

[0151] (3) Carbon disulfide is filled into the core layer of the solid-liquid composite hollow fiber confined by aerogel obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0152] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.629, a skin refractive index of 1.501, a numerical aperture of 0.633, an optical attenuation coefficient of 5.0 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light transmission diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a tensile strength of 2.46 MPa, a tensile elongation at break of 32%, and a bending stiffness of 25 E. -10 N m 2 The minimum bending radius is 0.5 mm.

[0153] Example 14

[0154] (1) Hollow polyamide wet gel fibers are obtained by forming polyamide precursor solution into fibers through a mold, and polyamide aerogel hollow fibers are obtained by supercritical drying of the hollow polyamide wet gel fibers.

[0155] (2) The polyamide aerogel hollow fiber obtained in step (1) is fully soaked in perfluoropolyether oil for 6 h to obtain aerogel-confined solid-liquid composite hollow fiber.

[0156] (3) Carbon disulfide is filled into the core layer of the solid-liquid composite hollow fiber confined by aerogel obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0157] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.629, a skin refractive index of 1.310, a numerical aperture of 0.968, an optical attenuation coefficient of 0.1 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light transmission diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a tensile strength of 1.5 MPa, a breaking elongation of 10%, and a bending stiffness of 90°E. -10 N m 2 The minimum bending radius is 0.9 mm.

[0158] Example 15

[0159] (1) Hollow titanium dioxide wet gel fibers are obtained by forming titanium dioxide precursor solution into fibers through a mold, and titanium dioxide aerogel hollow fibers are obtained by supercritical drying of the hollow titanium dioxide wet gel fibers.

[0160] (2) The titanium dioxide aerogel hollow fiber obtained in step (1) is fully soaked in silicone oil for 6 h to obtain aerogel-confined solid-liquid composite hollow fiber.

[0161] (3) Carbon disulfide is filled into the core layer of the solid-liquid composite hollow fiber confined by aerogel obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0162] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.629, a skin refractive index of 1.380, a numerical aperture of 0.866, an optical attenuation coefficient of 0.5 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light transmission diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a tensile strength of 0.8 MPa, a breaking elongation of 5.0%, and a bending stiffness of 100 E. -10 N m 2 The minimum bending radius is 1.5 mm.

[0163] Comparative Example 1

[0164] (1) Hollow aromatic polyamide wet gel fibers were obtained by coaxial wet spinning of aromatic polyamide nanofiber dispersion, and aromatic polyamide hydrogel hollow fibers were obtained by solvent replacement of hollow aromatic polyamide wet gel fibers.

[0165] (2) By pressure injection, silicone oil is filled into the core layer of the aromatic polyamide hydrogel hollow fiber prepared in step (2) to obtain a liquid-liquid optical fiber based on hydrogel hollow fiber.

[0166] The liquid-liquid optical fiber based on hydrogel hollow fiber obtained in this comparative example has a core refractive index of 1.404, a skin refractive index of 1.336, a numerical aperture of 0.432, an optical attenuation coefficient of 0.3 dB / cm, an outer diameter of 0.738 mm, an inner diameter (transmitting diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a tensile strength of 1.5 MPa, a breaking elongation of 20%, and a bending stiffness of 11 E. -10 N m 2 The minimum bending radius is 1.2 mm. The optical attenuation of the liquid-liquid optical fiber based on hydrogel hollow fiber increases after long-term immersion in water. After 5 days, the optical attenuation coefficient is 1.5 dB / cm.

[0167] Comparative Example 2

[0168] (1) Hollow aromatic polyamide wet gel fibers were obtained by coaxial wet spinning of aromatic polyamide nanofiber dispersion, and aromatic polyamide aerogel hollow fibers were obtained by supercritical drying of hollow aromatic polyamide wet gel fibers.

[0169] (2) The aromatic polyamide aerogel hollow fiber obtained in step (1) was not fully soaked in deionized water to obtain aerogel-confined solid-liquid composite hollow fiber.

[0170] (3) Silicone oil is filled into the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0171] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this comparative example has a core refractive index of 1.404, a skin refractive index of 1.334, a numerical aperture of 0.438, an optical attenuation coefficient of 1.6 dB / cm, an outer diameter of 0.738 mm, an inner diameter (transmitting diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a tensile strength of 1.8 MPa, a breaking elongation of 23%, and a bending stiffness of 12 E. -10 N m 2 The minimum bending radius is 1.0 mm. Compared with Example 1, the light attenuation of this comparative example is increased because a liquid-liquid interface with total internal reflection is not formed.

[0172] Comparative Example 3

[0173] (1) Hollow aromatic polyamide wet gel fibers were obtained by coaxial wet spinning of aromatic polyamide nanofiber dispersion, and aromatic polyamide aerogel hollow fibers were obtained by supercritical drying of hollow aromatic polyamide wet gel fibers.

[0174] (2) The aromatic polyamide aerogel hollow fiber obtained in step (1) is fully immersed in deionized water to obtain aerogel-confined solid-liquid composite hollow fiber as optical fiber for relevant tests.

[0175] The optical fiber obtained in this comparative example has a core refractive index of 1.0, a skin refractive index of 1.336, an outer diameter of 0.738 mm, an inner diameter (light transmission diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a tensile strength of 2.2 MPa, an elongation at break of 32%, and a bending stiffness of 15 E. -10 N m 2 The minimum bending radius is 0.8 mm. Compared with Example 1, the refractive index of the core layer in this comparative example is much smaller than that of the skin layer. No total internal reflection liquid-liquid interface is formed, and scattering and other losses occur during transmission, making it impossible to transmit light.

[0176] Comparative Example 4

[0177] (1) Hollow aromatic polyamide wet gel fibers were obtained by coaxial wet spinning of aromatic polyamide nanofiber dispersion, and aromatic polyamide aerogel hollow fibers were obtained by supercritical drying of hollow aromatic polyamide wet gel fibers.

[0178] (2) The aromatic polyamide aerogel hollow fiber obtained in step (1) is fully soaked in deionized water to obtain aerogel-confined solid-liquid composite hollow fiber.

[0179] (3) By pressure injection, perfluoropolyether oil is filled into the core layer of the solid-liquid composite hollow fiber confined by aerogel obtained in step (2) to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

[0180] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this comparative example has a core refractive index of 1.290, a skin refractive index of 1.336, an outer diameter of 0.738 mm, an inner diameter (light transmission diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a tensile strength of 2.1 MPa, a breaking elongation of 30%, and a bending stiffness of 1.2 E. -10 N m 2 The minimum bending radius is 0.6 mm. Compared with Example 1, the core refractive index of this comparative example is less than that of the skin. It does not form a total internal reflection interface and suffers losses such as scattering during transmission, thus failing to achieve light transmission.

[0181] Through Examples 1-15 and Comparative Examples 1-4, it can be found that the liquid-liquid optical fiber based on aerogel hollow fiber obtained by the above technical solution of the present invention has the characteristics of large core diameter, large numerical aperture, wide spectral transmission range, high light transmission efficiency, stable structure, and good bending performance. Moreover, the preparation process is simple and easy to carry out large-scale production.

[0182] It should be understood that the order of the steps or the order in which specific actions are performed is not particularly important, as long as the teachings of this invention remain operable. Furthermore, two or more steps or actions can be performed simultaneously.

[0183] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the described embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims.

Claims

1. A liquid-liquid optical fiber based on aerogel hollow fibers, characterized in that, The device includes a core layer and a skin layer covering the core layer. The skin layer includes aerogel hollow fibers and a skin layer liquid. The skin layer liquid fully impregnates and fills the porous skeleton of the aerogel hollow fibers to form aerogel-confined solid-liquid composite hollow fibers. The core layer includes a core layer liquid. The refractive index of the core layer liquid is greater than that of the skin layer liquid. The core layer liquid and the skin layer liquid are immiscible.

2. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 1, characterized in that: The difference between the refractive index of the core liquid and the refractive index of the skin liquid is 0.0001~1.

3. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 1, characterized in that: The cortical liquid includes any one or more of the following: pure water, aqueous solution, aqueous emulsion, aromatic hydrocarbon organic solvent, aliphatic hydrocarbon organic solvent, alicyclic hydrocarbon organic solvent, halogenated hydrocarbon organic solvent, alcohol organic solvent, ether organic solvent, ester organic solvent, ketone organic solvent, diol derivative organic solvent, oil liquid, acetonitrile, pyridine, phenol, and carbon disulfide.

4. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 1, characterized in that: The core liquid includes any one or a combination of two or more of the following: pure water, aqueous solution, aqueous emulsion, aromatic hydrocarbon organic solvent, aliphatic hydrocarbon organic solvent, alicyclic hydrocarbon organic solvent, halogenated hydrocarbon organic solvent, alcohol organic solvent, ether organic solvent, ester organic solvent, ketone organic solvent, diol derivative organic solvent, oil liquid, acetonitrile, pyridine, phenol, and carbon disulfide.

5. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 3 or 4, characterized in that: The aromatic hydrocarbon organic solvents include any one or a combination of two or more of benzene, toluene, xylene, and nitrobenzene.

6. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 3 or 4, characterized in that: The aliphatic hydrocarbon organic solvent includes any one or a combination of two or more of pentane, hexane, octane, tetradecane, and hexadecane.

7. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 3 or 4, characterized in that: The alicyclic hydrocarbon organic solvent includes any one or a combination of two or more of cyclohexane, cyclohexanone, and toluenecyclohexanone.

8. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 3 or 4, characterized in that: The halogenated hydrocarbon organic solvents include any one or a combination of two or more of chlorobenzene, dichlorobenzene, dichloromethane, trichloromethane, and tetrachloroethylene.

9. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 3 or 4, characterized in that: The alcoholic organic solvents include any one or a combination of two or more of methanol, ethanol, and isopropanol.

10. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 3 or 4, characterized in that: The ether-based organic solvents include petroleum ether and / or propylene oxide.

11. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 3 or 4, characterized in that: The ester organic solvents include any one or a combination of two or more of methyl acetate, ethyl acetate, and propyl acetate.

12. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 3 or 4, characterized in that: The ketone organic solvents include any one or a combination of two or more of acetone, methyl butyl ketone, and methyl isobutyl ketone.

13. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 3 or 4, characterized in that: The diol derivative organic solvents include any one or a combination of two or more of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether.

14. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 3 or 4, characterized in that: The oily liquids include any one or a combination of two or more of gasoline, silicone oil, kerosene, mineral oil, oleic acid, and perfluoropolyether oil.

15. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 1, characterized in that: The aerogel hollow fiber includes any one or a combination of two or more of the following: organic aerogel hollow fiber, inorganic aerogel hollow fiber, and organic-inorganic hybrid aerogel hollow fiber.

16. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 15, characterized in that: The organic aerogel hollow fibers include any one or a combination of two or more of the following: aromatic polyamide aerogel hollow fibers, cellulose aerogel hollow fibers, sodium alginate aerogel hollow fibers, chitosan aerogel hollow fibers, polyvinyl alcohol aerogel hollow fibers, silk fibroin aerogel hollow fibers, polyimide aerogel hollow fibers, polyurethane aerogel hollow fibers, polyurea aerogel hollow fibers, phenolic aerogel hollow fibers, polyamide aerogel hollow fibers, polyester aerogel hollow fibers, polyethylene aerogel hollow fibers, polystyrene aerogel hollow fibers, polypyrrole aerogel hollow fibers, and polyvinylidene chloride aerogel hollow fibers.

17. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 15, characterized in that: The inorganic aerogel hollow fiber includes any one or a combination of two or more of the following: silica aerogel hollow fiber, titanium dioxide aerogel hollow fiber, alumina aerogel hollow fiber, zirconium oxide aerogel hollow fiber, graphene aerogel hollow fiber, carbon nanotube aerogel hollow fiber, metal aerogel hollow fiber, carbide aerogel hollow fiber, and nitride aerogel hollow fiber.

18. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 15, characterized in that: The organic-inorganic hybrid aerogel hollow fiber is made from organic aerogel hollow fiber and inorganic aerogel hollow fiber.

19. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 1, characterized in that: The liquid-liquid optical fiber based on aerogel hollow fiber has a liquid-liquid soft interface.

20. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 1, characterized in that: The liquid-liquid optical fiber based on aerogel hollow fiber can achieve total internal reflection of light at a liquid-liquid interface with molecular-level roughness.

21. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 1, characterized in that: The liquid-liquid optical fiber based on aerogel hollow fiber has a breaking strength of 0.1~100 MPa, a breaking elongation of 5%~1000%, and a bending stiffness of 0.1~10000E. -10 N m 2 The minimum bending radius is 0.01~1000 mm.

22. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 1, characterized in that: The liquid-liquid optical fiber based on aerogel hollow fiber has an outer diameter of 0.01~100 mm and an inner diameter of 0.01~100 mm.

23. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 22, characterized in that: The liquid-liquid optical fiber based on aerogel hollow fiber has an outer diameter of 0.01~20 mm and an inner diameter of 0.01~20 mm.

24. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 1, characterized in that: The sheath thickness of the liquid-liquid optical fiber based on aerogel hollow fiber is 0.01~100 mm.

25. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 24, characterized in that: The sheath thickness of the liquid-liquid optical fiber based on aerogel hollow fiber is 0.01~20 mm.

26. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 1, characterized in that: The liquid-liquid optical fiber based on aerogel hollow fiber has a numerical aperture of 0.1~1.5, a wavelength range of 0.01~100 μm for transmitted light, a light transmittance of 1%~100%, and a light attenuation coefficient of 0.001~100 dB / cm.

27. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 26, characterized in that: The numerical aperture of the liquid-liquid optical fiber based on aerogel hollow fiber is 0.1~1.

28. A method for fabricating a liquid-liquid optical fiber based on aerogel hollow fibers, characterized in that, include: Preparation of aerogel hollow fibers; The aerogel hollow fiber is fully impregnated with a skin liquid and filled into the porous skeleton of the aerogel hollow fiber to obtain aerogel-confined solid-liquid composite hollow fiber, which serves as the skin layer. A liquid core is filled inside the solid-liquid composite hollow fiber to form a core layer, thereby producing a liquid-liquid optical fiber based on aerogel hollow fiber. The refractive index of the core liquid is greater than that of the skin liquid, and the core liquid and the skin liquid are immiscible.

29. The preparation method according to claim 28, characterized in that, include: Aerogel hollow fibers were prepared from the spinning solution through spinning technology and drying treatment. The spinning solution includes any one or a combination of two or more of the following: aromatic polyamide molecular solution, aromatic polyamide nanofiber solution, cellulose solution, cellulose nanofiber dispersion, sodium alginate solution, chitosan solution, polyvinyl alcohol solution, silk fibroin protein solution, polyimide precursor solution, polyurethane solution, phenolic precursor solution, polyurea precursor solution, polyamide precursor solution, polyester precursor solution, polyethylene precursor solution, polystyrene precursor solution, polypyrrole gas precursor solution, polyvinylidene chloride precursor solution, silica sol, titanium dioxide precursor solution, alumina precursor solution, zirconium oxide precursor solution, graphene dispersion, carbon nanotube dispersion, metal precursor solution, carbide precursor solution, and nitride precursor solution.

30. The preparation method according to claim 29, characterized in that: The spinning technology includes spinning filaments using hollow spinnerets or coaxial needles through any one or a combination of two or more of the following methods: gel spinning, wet spinning, dry spinning, dry-jet wet spinning, dry cryogenic spinning, 3D printing, and mold-based filament formation.

31. The preparation method according to claim 29, characterized in that: The drying process includes any one or a combination of two or more of the following: supercritical fluid drying, vacuum freeze drying, reduced pressure drying, and atmospheric pressure drying.

32. The preparation method according to claim 28, characterized in that: The time for full immersion is 1 min to 48 h.

33. The preparation method according to claim 28, characterized in that... include: By pressure injection, core liquid is filled into the core layer of the solid-liquid composite hollow fiber to obtain a liquid-liquid optical fiber based on aerogel hollow fiber.

34. The preparation method according to claim 28, characterized in that: The difference between the refractive index of the core liquid and the refractive index of the skin liquid is 0.0001~1.

35. The preparation method according to claim 34, characterized in that: The cortical liquid includes any one or more of the following: pure water, aqueous solution, aqueous emulsion, aromatic hydrocarbon organic solvent, aliphatic hydrocarbon organic solvent, alicyclic hydrocarbon organic solvent, halogenated hydrocarbon organic solvent, alcohol organic solvent, ether organic solvent, ester organic solvent, ketone organic solvent, diol derivative organic solvent, oil liquid, acetonitrile, pyridine, phenol, and carbon disulfide.

36. The preparation method according to claim 34, characterized in that: The core liquid includes any one or a combination of two or more of the following: pure water, aqueous solution, aqueous emulsion, aromatic hydrocarbon organic solvent, aliphatic hydrocarbon organic solvent, alicyclic hydrocarbon organic solvent, halogenated hydrocarbon organic solvent, alcohol organic solvent, ether organic solvent, ester organic solvent, ketone organic solvent, diol derivative organic solvent, oil liquid, acetonitrile, pyridine, phenol, and carbon disulfide.

37. The preparation method according to claim 35 or 36, characterized in that: The aromatic hydrocarbon organic solvents include any one or a combination of two or more of benzene, toluene, xylene, and nitrobenzene.

38. The preparation method according to claim 35 or 36, characterized in that: The aliphatic hydrocarbon organic solvent includes any one or a combination of two or more of pentane, hexane, octane, tetradecane, and hexadecane.

39. The preparation method according to claim 35 or 36, characterized in that: The alicyclic hydrocarbon organic solvent includes any one or a combination of two or more of cyclohexane, cyclohexanone, and toluenecyclohexanone.

40. The preparation method according to claim 35 or 36, characterized in that: The halogenated hydrocarbon organic solvents include any one or a combination of two or more of chlorobenzene, dichlorobenzene, dichloromethane, trichloromethane, and tetrachloroethylene.

41. The preparation method according to claim 35 or 36, characterized in that: The alcoholic organic solvents include any one or a combination of two or more of methanol, ethanol, and isopropanol.

42. The preparation method according to claim 35 or 36, characterized in that: The ether-based organic solvents include petroleum ether and / or propylene oxide.

43. The preparation method according to claim 35 or 36, characterized in that: The ester organic solvents include any one or a combination of two or more of methyl acetate, ethyl acetate, and propyl acetate.

44. The preparation method according to claim 35 or 36, characterized in that: The ketone organic solvents include any one or a combination of two or more of acetone, methyl butyl ketone, and methyl isobutyl ketone.

45. The preparation method according to claim 35 or 36, characterized in that: The diol derivative organic solvents include any one or a combination of two or more of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether.

46. ​​The preparation method according to claim 35 or 36, characterized in that: The oily liquids include any one or a combination of two or more of gasoline, silicone oil, kerosene, mineral oil, oleic acid, and perfluoropolyether oil.

47. A liquid-liquid optical fiber based on aerogel hollow fiber prepared by any one of claims 28-36.

48. The application of the liquid-liquid optical fiber based on aerogel hollow fiber according to any one of claims 1-27 and 47 in the fields of optical transmission, optical communication, optical sensing, illumination, Raman spectroscopy or nonlinear optics.

49. The application according to claim 48, characterized in that, The applications include: the application of the liquid-liquid optical fiber based on aerogel hollow fiber in the fields of underwater optical communication, underwater optical sensing or underwater optical fiber lighting.

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