Liquid-liquid optical fiber based on aerogel hollow fiber as well as preparation method and application of liquid-liquid optical fiber

Abstract

The invention discloses a liquid-liquid optical fiber based on aerogel hollow fibers and a preparation method and application thereof. The liquid-liquid optical fiber comprises a core layer and a skin layer wrapping the core layer, the skin layer comprises aerogel hollow fibers and skin layer liquid, porous frameworks of the aerogel hollow fibers are infiltrated and filled with the skin layer liquid to form aerogel confined solid-liquid composite hollow fibers, the core layer comprises core layer liquid, and the core layer liquid is filled with the skin layer liquid to form aerogel confined solid-liquid composite hollow fibers. And the refractive index of the core layer liquid is greater than that of the skin layer liquid. The liquid-liquid optical fiber provided by the invention has excellent mechanical properties, the reflection interface of the liquid-liquid optical fiber is a liquid-liquid interface, and the fiber core is free-flowing liquid, so that when the liquid optical fiber is bent, the liquid can be transferred to the surrounding, the liquid-liquid optical fiber has excellent flexibility and deformation resistance, and the reconfigurability of refraction of the skin layer and the core layer can be realized at the same time; the method can be applied to the fields of optical transmission, optical communication, optical sensing, illumination, Raman spectrum, nonlinear optics and the like.

Description

Technical Field

[0001] The present invention relates to a novel optical fiber technology, in particular to a liquid-liquid optical fiber based on aerogel hollow fiber and a preparation method and application thereof, belonging to the technical field of nanoporous materials and functional fibers. Background Art

[0002] Optical fiber is the abbreviation of optical fiber, which can be used as a medium for optical signal transmission. Its transmission principle is total internal reflection of light. Optical fiber can be divided into communication fiber and functional fiber. Communication fiber is the most important application area of ​​optical fiber. Functional fiber can be divided into energy transmission fiber, image transmission fiber and sensor fiber, which are promising areas for development. Optical fiber technology has become the core technology that dominates the global communication network due to its advantages such as long transmission distance, strong anti-interference ability, large bandwidth, good stability and high security. In addition, the continuous development of optical fiber technology has also brought great changes to medical treatment, medical equipment, sensing and other fields. Traditional optical fiber is made of glass or polymer as raw materials. The interface for achieving total reflection of light is generally a solid-solid interface. Due to its relatively large rigidity, it is difficult to achieve bending with a small radius of curvature, resulting in poor flexibility and poor weaving ability. The modulus is also relatively high, which limits the feasibility of optical fiber in emerging diversified application fields, such as flexible wearables, smart fabrics, portable functional devices / equipment, etc.

[0003] In recent years, researchers have used hydrogels to prepare hydrogel optical fibers because of their excellent flexibility and biocompatibility. Patent CN110541209A invented a continuous preparation method for hydrogel optical fibers based on reactive spinning, including: skin spinning solution, core spinning solution, using a transverse coaxial needle as a spinning nozzle, using CaCl2 aqueous solution as a coagulation bath to solidify the skin sodium alginate, and using an ultraviolet light source to initiate the free radical polymerization reaction of PEGDA in the core spinning solution; after drawing, a skin-core structure hydrogel optical fiber with good biocompatibility is finally obtained. Similar hydrogel optical fibers have the following problems: (1) Hydrogel optical fibers are easy to swell and are easily affected by permeable substances, resulting in unstable optical waveguide performance, which in turn affects its light transmission, sensing, etc.; (2) Since the monomer polymerization process easily leads to defects such as molecular chain entanglement and uneven pore structure, it is difficult to prepare highly transparent hydrogel materials; (3) Limited by the fixedness of the optical path, the introduction of functional phases is limited; (4) The refractive index difference between the inner and outer layers is relatively small, resulting in a relatively small numerical aperture, resulting in a relatively weak ability of the optical fiber to receive light. Patent CN109898176A invented a flexible and stretchable hydrogel optical fiber, the optical fiber is a skin-core structure, wherein the skin layer is a transparent silicone capillary; the core layer 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 larger than the modulus 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 optical fiber is different from common quartz optical fiber. It is composed 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 hard material as a transparent light window. The light is transmitted by total reflection inside the core. The core of liquid core optical fiber is filled with liquid, so it has advantages that quartz optical fiber, plastic optical fiber and hydrogel optical fiber cannot match. For example, the core is filled with liquid that can flow freely. When the optical fiber is bent, the stress generated inside can be released to the surrounding through the liquid. The bending radius of the optical fiber can be very large, and the availability is increased, avoiding the damage that was easily caused by bending of quartz optical fiber in the past. In addition, the core liquid can be replaced as needed to obtain apertures of different values, meeting various practical needs, and the numerical aperture can be made higher, so that the utilization rate of light energy is improved. Patent CN109946788A proposes a reconfigurable liquid core fiber, which can output lasers of different wavelengths, thereby improving the applicability of the laser. The reconfigurable liquid core fiber includes a first sub-fiber, a second sub-fiber and a third sub-fiber connected in sequence; the second sub-fiber includes a second core, the second core is a hollow structure, and the first sub-fiber and the third sub-fiber together form a resonant cavity for the second sub-fiber; wherein the second sub-fiber is provided with a liquid circulation channel, the liquid circulation channel is connected to the second core, and the liquid circulation channel is used to inject and discharge liquid dye into the second core, thereby forming a reconfigurable liquid core fiber. In addition, patent CN114163676A provides a liquid core hydrogel fiber, including a hollow hydrogel core, a liquid core located in the hollow hydrogel core, and a hydrogel cladding coated on the surface of the hollow hydrogel core. The liquid core hydrogel fiber combines the advantages of hydrogel fiber and liquid core fiber, and has the advantages of high light transmission efficiency, good flexibility, and a wide range of applications. However, inevitably, due to its hydrogel cladding, the liquid core hydrogel optical fiber is firstly easy to swell, resulting in the total light reflection interface being affected, thereby affecting the light transmission performance; secondly, the cladding material is fixed to the hydrogel material, and the cladding material cannot be replaced in time according to actual needs; thirdly, since the light transmitting liquid core and the sensing liquid core of the liquid core are both soluble in water, the liquid core material is easy to diffuse into the cladding hydrogel, resulting in no obvious total light reflection interface between the cladding and the core, the light loss is relatively serious and the light transmission stability is poor.

[0005] Aerogel material is a new type of lightweight and porous synthetic material. The preparation process usually requires supercritical drying or freeze drying to replace the liquid in the wet gel with gas without significantly changing the network structure of the gel. Therefore, it has unique properties such as extremely small apparent density and thermal conductivity, high porosity and specific surface area. Aerogel fibers not only maintain their aerogel properties, but also give them the characteristics of being slender and soft, which will further broaden the application field of aerogel materials. Compared with hydrogel fibers, aerogel fibers have a robust network skeleton structure that does not swell when exposed to water, and based on the nano-confinement effect of their mesopores, aerogel fibers can well confine various functional liquids.

[0006] In summary, there is no optical fiber based on aerogel materials, and the development of optical fiber technology based on aerogel materials has incomparable challenges. There is no optical fiber that can simultaneously achieve the refractive index reconfigurability of the skin and core layers. Summary of the invention

[0007] The main purpose of the present invention is to provide a liquid-liquid optical fiber based on aerogel hollow fiber and a preparation method thereof, so as to overcome the deficiencies in the prior art.

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

[0009] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: An embodiment of the present invention provides a liquid-liquid optical fiber based on aerogel hollow fiber, which includes a core layer and a skin layer covering the core layer, the skin layer includes aerogel hollow fiber and a skin layer liquid, the skin layer liquid is infiltrated and filled in the porous skeleton of the aerogel hollow fiber to form an aerogel confined solid-liquid composite hollow fiber, the core layer includes a core layer liquid, and the refractive index of the core layer liquid is greater than the refractive index of the skin layer liquid.

[0010] The embodiment of the present invention also provides a method for preparing a liquid-liquid optical fiber based on aerogel hollow fiber, which comprises: preparing aerogel hollow fibers; The aerogel hollow fiber is infiltrated with a cortex liquid and filled into the porous skeleton of the aerogel hollow fiber to obtain an aerogel-confined solid-liquid composite hollow fiber as a cortex; The core layer liquid is filled into the solid-liquid composite hollow fiber as the core layer to obtain a liquid-liquid optical fiber based on aerogel hollow fiber, wherein the refractive index of the core layer liquid is greater than the refractive index of the skin layer liquid.

[0011] The embodiment of the present invention also provides a liquid-liquid optical fiber based on aerogel hollow fiber prepared by the above-mentioned preparation method.

[0012] The embodiment of the present invention also provides the application of the liquid-liquid optical fiber based on aerogel hollow fiber in the fields of optical transmission, optical communication, optical sensing, lighting, Raman spectroscopy or nonlinear optics.

[0013] Compared with the prior art, the beneficial effects of the present invention include at least: 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 skin and core, and can obtain an optical fiber with a large numerical aperture; the liquid-liquid optical fiber has excellent mechanical properties, the reflection 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 transferred to the surroundings, and has excellent flexibility and anti-deformation ability; 2) Compared with hydrogel optical fiber, the aerogel cortex of 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, and based on the nano-confinement effect of its mesopores, the cortex can not only confine water, but also various functional liquids, thereby giving the liquid-liquid optical fiber various functionalities; 3) Compared with commercial liquid core optical fibers, the liquid-liquid optical fiber based on aerogel hollow fiber provided by the present invention can achieve reconfigurability not only in the core layer liquid, but also in the skin layer by infiltrating different liquids. The liquid-liquid optical fiber can simultaneously achieve the refraction reconfigurability of the skin layer and the core layer; 4) The liquid-liquid optical fiber based on aerogel hollow fiber provided by the present invention is a new type of optical fiber, which fills the gap in aerogel-based optical fiber materials and promotes the application of optical fiber in the fields of 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 It is a structural schematic diagram and light transmission schematic diagram of a liquid-liquid optical fiber based on aerogel hollow fiber in a typical embodiment of the present invention; Figure 2 is a scanning electron microscope photograph of the aerogel hollow fiber obtained in Example 1 of the present invention; Figure 3 It is a schematic diagram of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in Example 1 of the present invention for laser light waveguides of different wavelengths; Figure 4This is a diameter comparison photo of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in Example 2 of the present invention before and after being immersed in pure water for 2 days; Figure 5 is a tensile curve diagram of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in Example 2 of the present invention; Figure 6 These are digital photos of the optical waveguide of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in Example 2 of the present invention at different bending angles. DETAILED DESCRIPTION

[0016] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice, which mainly provides a liquid-liquid optical fiber based on aerogel hollow fiber, its preparation method and application, fills the gap in optical fiber technology based on aerogel materials, and aims to solve the thorny problems in the prior art that hydrogel optical fiber is easy to swell and the refractive index of the skin and core layer cannot be reconstructed at the same time in the prior optical fiber technology. The technical solution, its implementation process and principle will be further explained as follows.

[0017] As one aspect of the technical solution of the present invention, a liquid-liquid optical fiber based on aerogel hollow fiber comprises a core layer and a sheath layer covering the core layer, wherein the sheath layer comprises an aerogel hollow fiber and a sheath liquid, wherein the sheath liquid is infiltrated and filled in the porous skeleton of the aerogel hollow fiber to form an aerogel-confined solid-liquid composite hollow fiber, and the core layer comprises a core layer liquid.

[0018] In some embodiments, the core layer liquid and the skin layer liquid are immiscible with each other and exist stably with each other.

[0019] In some embodiments, the core liquid has a refractive index greater than the refractive index of the skin liquid.

[0020] Furthermore, the difference between the refractive index of the core layer liquid and the refractive index of the skin layer liquid is 0.0001-1.

[0021] In some embodiments, the cortical liquid may include any one or a combination of two or more of 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, diol derivative organic solvents, oil liquids, acetonitrile, pyridine, phenol, carbon disulfide, etc., but is not limited thereto.

[0022] In some embodiments, the core layer liquid may include any one or a combination of two or more of 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 to these.

[0023] Furthermore, the above-mentioned aromatic hydrocarbon organic solvent may include any one or a combination of two or more of benzene, toluene, xylene, nitrobenzene, etc., but is not limited thereto.

[0024] 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 thereto.

[0025] Furthermore, the alicyclic hydrocarbon organic solvent may include any one or a combination of two or more of cyclohexane, cyclohexanone, toluene, cyclohexanone, etc., but is not limited thereto.

[0026] Furthermore, the halogenated hydrocarbon organic solvent may include any one or a combination of two or more of chlorobenzene, dichlorobenzene, dichloromethane, chloroform, tetrachloroethylene, etc., but is not limited thereto.

[0027] Furthermore, the alcohol organic solvent may include any one or a combination of two or more of methanol, ethanol, isopropanol, etc., but is not limited thereto.

[0028] Furthermore, the ether organic solvent may include any one or a combination of two of petroleum ether, propylene oxide, etc., but is not limited thereto.

[0029] 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 thereto.

[0030] Furthermore, the ketone organic solvent includes any one or a combination of two or more of acetone, methyl butyl ketone, methyl isobutyl ketone, etc., but is not limited thereto.

[0031] 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, ethylene glycol monobutyl ether, etc., but is not limited thereto.

[0032] Furthermore, the oil 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 thereto.

[0033] In some embodiments, the aerogel hollow fiber includes any one or a combination of two or more of organic aerogel hollow fiber, inorganic aerogel hollow fiber, organic-inorganic hybrid aerogel hollow fiber, etc., but is not limited thereto.

[0034] In some more preferred embodiments, the organic aerogel hollow fiber may include any one or a combination of two or more of 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, polyvinylidene chloride aerogel hollow fiber, etc., but is not limited thereto.

[0035] In some preferred embodiments, the inorganic aerogel hollow fiber may include any one or a combination of two or more of silica aerogel hollow fiber, titanium oxide aerogel hollow fiber, aluminum oxide 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.

[0036] In some preferred embodiments, the organic-inorganic hybrid aerogel hollow fibers are prepared from the aforementioned organic aerogel hollow fibers and inorganic aerogel hollow fibers.

[0037] In some embodiments, the aerogel hollow fiber-based liquid-liquid optical fiber has a liquid-liquid soft interface and thus has excellent flexibility.

[0038] Furthermore, the interface of the liquid-liquid optical fiber based on aerogel hollow fiber that can achieve total internal reflection of light is a liquid-liquid interface with molecular-level roughness.

[0039] In some embodiments, 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 0.01~1000mm.

[0040] In some embodiments, the outer diameter of the aerogel hollow fiber-based liquid-liquid optical fiber is 0.01-100 mm, preferably 0.01-20 mm, and the inner diameter (light-transmitting diameter) is 0.01-100 mm, preferably 0.01-20 mm.

[0041] In some embodiments, the skin thickness of the aerogel hollow fiber-based liquid-liquid optical fiber is 0.01-100 mm, preferably 0.01-20 mm.

[0042] In some embodiments, the numerical aperture of the aerogel hollow fiber-based liquid-liquid optical fiber is 0.1-1.5, preferably 0.1-1, the wavelength range of the transmitted light is 0.01-100 μm, the light transmittance is 1%-100%, and the light attenuation coefficient is 0.001-100 dB / cm.

[0043] 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 principle of light transmission is the total internal reflection of light. When light is emitted from the core part with high refractive index to the cladding part with low refractive index, if the incident angle is greater than or equal to the critical angle of total reflection, the light will no longer be refracted but will be completely reflected back to the core part. This phenomenon is called total reflection. The n2>n1>n0 of the liquid-liquid optical fiber based on aerogel hollow fiber. Due to the effect of total internal reflection, the light can be continuously reflected and advanced in the core layer of the liquid-liquid optical fiber based on aerogel hollow fiber, thereby realizing light transmission, wherein n0 is the refractive index of air, n1 is the refractive index of the skin, and n2 is the refractive index of the core liquid.

[0044] Furthermore, compared with ordinary quartz glass optical fibers, which transmit light over a wide wavelength range, quartz optical fibers absorb light in the ultraviolet region below 300 nm and have large light losses, making them unsuitable for ultraviolet light transmission. Ultraviolet light curing, fluorescence detection and other fields require optical fibers that can transmit ultraviolet light.

[0045] 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 inner core and the cladding of the optical fiber is very small, resulting in a small numerical aperture. The liquid-liquid optical fiber of the present invention has a wide range of selectable liquids in the skin and core, and an optical fiber with a large numerical aperture can be obtained.

[0046] 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 reflection 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 transferred to the surroundings, and it has excellent flexibility and deformation resistance.

[0047] Furthermore, compared with hydrogel optical fiber, the liquid-liquid optical fiber of the present invention does not swell in water due to the robust network skeleton structure of the aerogel cortex, and based on the nano-confinement effect of its mesopores, the cortex can not only confine water, but also can well confine various functional liquids, thereby giving the liquid-liquid optical fiber various functionalities.

[0048] Furthermore, compared with commercial liquid core optical fibers, in addition to the core liquid that can achieve reconfiguration, the skin layer of liquid-liquid optical fibers can also achieve reconfiguration by infiltrating different types of liquids. Liquid-liquid optical fibers can simultaneously achieve reconfiguration of the refraction of the skin and core layer.

[0049] Specifically, as another aspect of the technical solution of the present invention, a method for preparing a liquid-liquid optical fiber based on aerogel hollow fiber includes: preparing aerogel hollow fibers; The aerogel hollow fiber is infiltrated with a cortex liquid and filled into the porous skeleton of the aerogel hollow fiber to obtain an aerogel-confined solid-liquid composite hollow fiber as a cortex; The core layer liquid is filled into the solid-liquid composite hollow fiber as the core layer to obtain a liquid-liquid optical fiber based on aerogel hollow fiber, wherein the refractive index of the core layer liquid is greater than the refractive index of the skin layer liquid.

[0050] The preparation method provided by the present invention mainly takes aerogel hollow fiber as a model. Based on the nano-confinement effect of aerogel on liquid, two immiscible liquids with different refractive indices are filled in the cortex and core layer of the aerogel fiber respectively (the refractive index of the core layer liquid is greater than the refractive index of the cortex layer liquid), forming a liquid-liquid interface to achieve total internal reflection of light and thus realize optical waveguide.

[0051] In some embodiments, the preparation method comprises: preparing aerogel hollow fibers through spinning technology and drying treatment of the spinning solution.

[0052] In some more preferred embodiments, the spinning solution can include any one or a combination of two or more of an aromatic polyamide molecular solution, an aromatic polyamide nanofiber solution, a cellulose solution, a cellulose nanofiber dispersion, a sodium alginate solution, a chitosan solution, a polyvinyl alcohol solution, a silk fibroin solution, a polyimide precursor solution, a polyurethane solution, a phenolic precursor solution, a polyurea precursor solution, a polyamide precursor solution, a polyester precursor solution, a polyethylene precursor solution, a polystyrene precursor solution, a polypyrrole precursor solution, a polyvinylidene chloride precursor solution, a silica sol, a titanium oxide precursor solution, an aluminum oxide precursor solution, a zirconium oxide precursor solution, a graphene dispersion, a carbon nanotube dispersion, a metal precursor solution, a carbide precursor solution, a nitride precursor solution, etc., but is not limited thereto.

[0053] In some more preferred embodiments, the spinning technology includes using a hollow spinneret or a coaxial needle to form filaments through any one or a combination of two or more of gel spinning, wet spinning, dry spinning, dry-jet wet spinning, dry freeze spinning, 3D printing, mold filamentation, etc., but is not limited to these.

[0054] In some more preferred embodiments, the drying process may include any one or a combination of two or more of supercritical fluid drying, vacuum freeze drying, reduced pressure drying, and normal pressure drying, but is not limited thereto.

[0055] In some embodiments, the infiltration time is 1 min to 48 h.

[0056] In some embodiments, the preparation method includes: filling the core layer of the solid-liquid composite hollow fiber with a core layer liquid by pressure injection to obtain a liquid-liquid optical fiber based on an aerogel hollow fiber.

[0057] In some embodiments, the core layer liquid and the skin layer liquid used in the preparation method are as defined above.

[0058] In some specific embodiments, the cortical liquid includes pure water; aqueous solution; aqueous emulsion; aromatic hydrocarbon organic solvents such as benzene, toluene, xylene, nitrobenzene, etc.; aliphatic hydrocarbon organic solvents such as pentane, hexane, octane, tetradecane, hexadecane, etc.; alicyclic hydrocarbon organic solvents such as cyclohexane, cyclohexanone, toluene cyclohexanone, etc.; halogenated hydrocarbon organic solvents such as chlorobenzene, dichlorobenzene, dichloromethane, chloroform, tetrachloroethylene, etc.; alcohol organic solvents such as methanol, ethanol, isopropanol, etc.; 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 derivative organic solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether; and organic solvents such as acetonitrile, pyridine, phenol, and carbon disulfide; oil liquids such as gasoline, silicone oil, kerosene, mineral oil, oleic acid, and perfluoropolyether oil; any one or a combination of two or more of the above liquids, but not limited to these.

[0059] In some specific embodiments, the core layer liquid includes pure water; aqueous solution; aqueous emulsion; aromatic hydrocarbon organic solvents such as benzene, toluene, xylene, nitrobenzene, etc.; aliphatic hydrocarbon organic solvents such as pentane, hexane, octane, tetradecane, hexadecane, etc.; alicyclic hydrocarbon organic solvents such as cyclohexane, cyclohexanone, toluene cyclohexanone, etc.; halogenated hydrocarbon organic solvents such as chlorobenzene, dichlorobenzene, dichloromethane, chloroform, tetrachloroethylene, etc.; alcohol organic solvents such as methanol, ethanol, isopropanol, etc.; 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 derivative organic solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether; and organic solvents such as acetonitrile, pyridine, phenol, and carbon disulfide; oil liquids such as gasoline, silicone oil, kerosene, mineral oil, oleic acid, and perfluoropolyether oil; any one or a combination of two or more of the above liquids, but not limited to these.

[0060] Among them, in some more specific embodiments, the preparation method of the liquid-liquid optical fiber based on aerogel hollow fiber comprises the following steps: (1) preparing aerogel hollow fibers by coaxial spinning and drying the spinning solution; (2) selecting a cortical liquid to infiltrate the aerogel hollow fiber and fill it into the porous skeleton of the aerogel hollow fiber to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) A core layer liquid is selected and 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.

[0061] In summary, the preparation method of the present invention has a simple operation process, a short preparation cycle, a low production cost, is easy to mass produce, and does not require expensive instruments such as optical fiber fusion splicers.

[0062] 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.

[0063] Another aspect of the embodiments of the present invention further provides the application of the aforementioned liquid-liquid optical fiber based on aerogel hollow fiber.

[0064] The liquid-liquid optical fiber based on aerogel hollow fiber provided by the present invention is a new type of optical fiber, which fills the gap in aerogel-based optical fiber materials. The liquid-liquid optical fiber has optical waveguide properties, which promotes its application in the fields of 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.

[0065] In summary, compared with the previous optical fiber preparation method, the preparation method of the liquid-liquid optical fiber based on aerogel hollow fiber provided by the present invention has the advantages of being simple and easy to operate and not requiring expensive equipment (such as an optical fiber fusion splicer), and the obtained liquid-liquid optical fiber has the characteristics of large core diameter, large numerical aperture, wide spectral transmission range, high light transmission efficiency, good bending performance, etc. The obtained liquid-liquid optical fiber can be used in the fields of 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.

[0066] The technical scheme of the present invention is further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only used to illustrate the present invention, but not to limit the scope of the present invention, and those skilled in the art can adjust according to actual conditions. The implementation conditions adopted in the following examples can be further adjusted according to actual needs, and the implementation conditions not specified are usually the conditions in routine experiments.

[0067] Example 1 (1) preparing hollow aromatic polyamide wet gel fibers from an aromatic polyamide nanofiber dispersion by a coaxial wet spinning method, and preparing hollow aromatic polyamide wet gel fibers by supercritical drying to obtain aromatic polyamide aerogel hollow fibers; (2) soaking the aromatic polyamide aerogel hollow fiber obtained in step (1) in deionized water for 12 hours to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) with silicone oil by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0068] 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, a light attenuation coefficient of 0.3dB / cm, an outer diameter of 0.738 mm, an inner diameter (light-transmitting diameter) of 0.464 mm, a thickness of the aerogel skin of 0.137 mm, a breaking strength of 2 MPa, a breaking elongation of 25%, and a bending stiffness of 12 E. -10 N m 2 , the minimum bending radius is 1.0 mm.

[0069] After the above steps, the scanning electron microscope image of the aerogel hollow fiber obtained in this embodiment is as follows: Figure 2 As shown, the schematic diagram of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment for laser light waveguides of different wavelengths is shown in Figure 3 shown.

[0070] Example 2 (1) preparing hollow aromatic polyamide wet gel fibers from an aromatic polyamide nanofiber dispersion by a coaxial wet spinning method, and preparing hollow aromatic polyamide wet gel fibers by supercritical drying to obtain aromatic polyamide aerogel hollow fibers; (2) soaking the aromatic polyamide aerogel hollow fiber obtained in step (1) in deionized water for 24 hours to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) with tetradecane by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0071] 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, a light attenuation coefficient of 0.5 dB / cm, an outer diameter of 1.2 mm, an inner diameter (light-transmitting diameter) of 0.9 mm, a thickness of the aerogel skin of 0.15 mm, a breaking strength of 8 MPa, a breaking elongation of 40%, and a bending stiffness of 120 E. -10 N m 2 , the minimum bending radius is 0.7 mm.

[0072] After the above steps, the diameter comparison of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment before and after being immersed in pure water for 2 days is as follows: Figure 4 As shown in FIG. 1 , the liquid-liquid optical fiber based on the aerogel hollow fiber does not swell in water; the tensile curve of the liquid-liquid optical fiber based on the aerogel hollow fiber obtained in this embodiment is shown in FIG. Figure 5 As shown; Digital photos of the optical waveguide of the liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment at different bending angles are shown Figure 6 shown.

[0073] Example 3 (1) Aromatic polyamide molecular solution is coaxially spun through a hollow spinneret to obtain hollow aromatic polyamide wet gel fibers, and the hollow aromatic polyamide wet gel fibers are subjected to vacuum freeze drying to obtain aromatic polyamide aerogel hollow fibers; (2) soaking the aromatic polyamide aerogel hollow fiber obtained in step (1) in deionized water for 5 minutes to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling nitrobenzene into the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0074] 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, a light attenuation coefficient of 0.2 dB / cm, an outer diameter of 0.01 mm, an inner diameter (light-transmitting diameter) of 0.004 mm, a thickness of the aerogel skin of 0.003 mm, a breaking strength of 32 MPa, a breaking elongation of 120%, and a bending stiffness of 60 E. -10 N m 2 , the minimum bending radius is 0.6 mm.

[0075] Example 4 (1) preparing hollow cellulose wet gel fibers from a cellulose nanofiber dispersion by a coaxial wet spinning method, and preparing cellulose aerogel hollow fibers by drying the hollow cellulose wet gel fibers under reduced pressure; (2) soaking the cellulose aerogel hollow fiber obtained in step (1) in perfluoropolyether oil for 1 minute to obtain aerogel-confined solid-liquid composite hollow fiber; (3) Filling cyclohexane into the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0076] 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, a light attenuation coefficient of 0.8 dB / cm, an outer diameter of 3 mm, an inner diameter (light-transmitting diameter) of 2 mm, a thickness of the aerogel skin of 0.5 mm, a breaking strength of 4 MPa, a breaking elongation of 500%, and a bending stiffness of 0.3 E -10 N m 2 , the minimum bending radius is 0.1 mm.

[0077] Example 5 (1) a sodium alginate solution is subjected to a coaxial wet spinning method to obtain a hollow sodium alginate wet gel fiber, and the hollow sodium alginate wet gel fiber is subjected to supercritical drying to obtain a sodium alginate aerogel hollow fiber; (2) Soaking the sodium alginate aerogel hollow fiber obtained in step (1) in a calcium chloride solution for 24 hours to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) with chloroform by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0078] 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, a light attenuation coefficient of 0.2 dB / cm, an outer diameter of 0.8 mm, an inner diameter (light-transmitting diameter) of 0.4 mm, a thickness of the aerogel skin of 0.2 mm, a breaking strength of 30 MPa, a breaking elongation of 1000%, and a bending stiffness of 20 E -10 N m 2 , the minimum bending radius is 0.4 mm.

[0079] Example 6 (1) The chitosan solution is subjected to a coaxial 3D printing method to obtain hollow chitosan wet gel fibers, and the hollow chitosan wet gel fibers are subjected to supercritical drying to obtain chitosan aerogel hollow fibers; (2) soaking the chitosan aerogel hollow fiber obtained in step (1) in perfluoropolyether oil for 36 hours to obtain aerogel-confined solid-liquid composite hollow fiber; (3) Filling carbon disulfide into the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0080] 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, a light attenuation coefficient of 0.01 dB / cm, an outer diameter of 1.5 mm, an inner diameter (light-transmitting diameter) of 0.5 mm, a thickness of the aerogel skin of 0.5 mm, a breaking 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.

[0081] Example 7 (1) spinning a polyvinyl alcohol solution through a coaxial dry-jet wet spinning method to obtain a hollow polyvinyl alcohol wet gel fiber, and drying the hollow polyvinyl alcohol wet gel fiber through supercritical drying to obtain a polyvinyl alcohol aerogel hollow fiber; (2) soaking the polyvinyl alcohol aerogel hollow fiber obtained in step (1) in a boric acid aqueous solution for 48 hours to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling tetrachloroethylene into the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0082] 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, a light attenuation coefficient of 5.0 dB / cm, an outer diameter of 5.0 mm, an inner diameter (light-transmitting diameter) of 3.0 mm, a thickness of the aerogel skin of 1.0 mm, a breaking strength of 6 MPa, a breaking elongation of 50%, and a bending stiffness of 15 E -10 N m 2 , the minimum bending radius is 0.5 mm.

[0083] Example 8 (1) The silica sol solution is subjected to a coaxial wet spinning method to obtain hollow silica wet gel fibers, and the hollow silica wet gel fibers are subjected to supercritical drying to obtain silica aerogel hollow fibers; (2) soaking the silica aerogel hollow fiber obtained in step (1) in perfluoropolyether oil for 12 hours to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) with silicone oil by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0084] 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, a light attenuation coefficient of 0.001 dB / cm, an outer diameter of 0.9 mm, an inner diameter (light-transmitting diameter) of 0.5 mm, a thickness of the aerogel skin of 0.2 mm, a breaking 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.

[0085] Example 9 (1) a polyimide precursor solution is passed through a die filament forming method to obtain a hollow polyimide wet gel fiber, and the hollow polyimide wet gel fiber is subjected to supercritical drying to obtain a polyimide aerogel hollow fiber; (2) soaking the polyimide aerogel hollow fiber obtained in step (1) in silicone oil for 6 hours to obtain aerogel-confined solid-liquid composite hollow fiber; (3) Filling oleic acid into the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0086] 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, a light attenuation coefficient of 100 dB / cm, an outer diameter of 1 mm, an inner diameter (light-transmitting diameter) of 0.8 mm, a thickness of the aerogel skin of 0.1 mm, a breaking strength of 100 MPa, a breaking elongation of 100%, and a bending stiffness of 0.1 E -10 N m 2 , the minimum bending radius is 0.01 mm.

[0087] Example 10 (1) preparing hollow aromatic polyamide wet gel fibers from an aromatic polyamide nanofiber dispersion by a coaxial wet spinning method, and preparing hollow aromatic polyamide wet gel fibers by supercritical drying to obtain aromatic polyamide aerogel hollow fibers; (2) soaking the aromatic polyamide aerogel hollow fiber obtained in step (1) in perfluoropolyether oil for 20 hours to obtain aerogel-confined solid-liquid composite hollow fiber; (3) Filling kerosene into the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0088] 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, a light attenuation coefficient of 1.1 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light-transmitting diameter) of 0.464 mm, a thickness of the aerogel skin of 0.137 mm, a breaking 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.

[0089] Embodiment 11 (1) preparing hollow aromatic polyamide wet gel fibers from an aromatic polyamide nanofiber dispersion by a coaxial wet spinning method, and preparing hollow aromatic polyamide wet gel fibers by supercritical drying to obtain aromatic polyamide aerogel hollow fibers; (2) soaking the aromatic polyamide aerogel hollow fiber obtained in step (1) in acetonitrile for 30 hours to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling n-hexane into the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0090] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.375, a skin refractive index of 1.350, a numerical aperture of 0.261, a light attenuation coefficient of 0.8 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light-transmitting diameter) of 0.464 mm, a thickness of the aerogel skin of 0.137 mm, a breaking strength of 1.7 MPa, a breaking elongation of 19%, and a bending stiffness of 9 E -10 N m 2 , the minimum bending radius is 0.9 mm.

[0091] Example 12 (1) preparing hollow aromatic polyamide wet gel fibers from an aromatic polyamide nanofiber dispersion by a coaxial wet spinning method, and preparing hollow aromatic polyamide wet gel fibers by supercritical drying to obtain aromatic polyamide aerogel hollow fibers; (2) soaking the aromatic polyamide aerogel hollow fiber obtained in step (1) in ethanol for 30 minutes to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling petroleum ether into the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0092] 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, a light attenuation coefficient of 0.4dB / cm, an outer diameter of 0.738 mm, an inner diameter (light-transmitting diameter) of 0.464 mm, a thickness of the aerogel skin of 0.137 mm, a breaking 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.

[0093] Embodiment 13 (1) obtaining hollow graphene wet gel fibers by a coaxial wet spinning method from a graphene dispersion, and obtaining graphene aerogel hollow fibers by supercritical drying from the hollow graphene wet gel fibers; (2) Soaking the graphene aerogel hollow fiber obtained in step (1) in silicone oil for 3 h to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling carbon disulfide into the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0094] 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, a light attenuation coefficient of 5.0 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light-transmitting diameter) of 0.464 mm, a thickness of the aerogel skin of 0.137 mm, a breaking strength of 2.46 MPa, a breaking elongation of 32%, and a bending stiffness of 25 E. -10 N m 2 , the minimum bending radius is 0.5 mm.

[0095] Embodiment 14 (1) a polyamide precursor solution is passed through a die to obtain a hollow polyamide wet gel fiber, and the hollow polyamide wet gel fiber is subjected to supercritical drying to obtain a polyamide aerogel hollow fiber; (2) soaking the polyamide aerogel hollow fiber obtained in step (1) in perfluoropolyether oil for 6 h to obtain aerogel-confined solid-liquid composite hollow fiber; (3) Filling carbon disulfide into the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0096] The liquid-liquid optical fiber based on aerogel hollow fiber obtained in this embodiment has a core refractive index of 1.629, a skin refractive index of 1.310, a numerical aperture of 0.968, a light attenuation coefficient of 0.1 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light-transmitting diameter) of 0.464 mm, a thickness of the aerogel skin of 0.137 mm, a breaking 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.

[0097] Embodiment 15 (1) a titanium oxide precursor solution is passed through a mold to obtain a hollow titanium oxide wet gel fiber, and the hollow titanium oxide wet gel fiber is subjected to supercritical drying to obtain a titanium oxide aerogel hollow fiber; (2) Soaking the titanium oxide aerogel hollow fiber obtained in step (1) in silicone oil for 6 hours to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling carbon disulfide into the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0098] 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, a light attenuation coefficient of 0.5 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light-transmitting diameter) of 0.464 mm, a thickness of the aerogel skin of 0.137 mm, a breaking 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.

[0099] Comparative Example 1 (1) preparing hollow aromatic polyamide wet gel fibers by coaxial wet spinning of an aromatic polyamide nanofiber dispersion, and performing solvent replacement on the hollow aromatic polyamide wet gel fibers to obtain aromatic polyamide hydrogel hollow fibers; (2) Filling the core layer of the aromatic polyamide hydrogel hollow fiber prepared in step (2) with silicone oil by pressure injection to obtain a liquid-liquid optical fiber based on the hydrogel hollow fiber.

[0100] The liquid-liquid optical fiber based on the 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, a light attenuation coefficient of 0.3 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light-transmitting diameter) of 0.464 mm, a thickness of the aerogel skin of 0.137 mm, a breaking 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, and the optical attenuation coefficient is 1.5 dB / cm after 5 days.

[0101] Comparative Example 2 (1) preparing hollow aromatic polyamide wet gel fibers from an aromatic polyamide nanofiber dispersion by a coaxial wet spinning method, and preparing hollow aromatic polyamide wet gel fibers by supercritical drying to obtain aromatic polyamide aerogel hollow fibers; (2) soaking the aromatic polyamide aerogel hollow fiber obtained in step (1) in deionized water to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling the core layer of the aerogel-confined solid-liquid composite hollow fiber obtained in step (2) with silicone oil by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0102] 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, a light attenuation coefficient of 1.6 dB / cm, an outer diameter of 0.738 mm, an inner diameter (light-transmitting diameter) of 0.464 mm, a thickness of the aerogel skin of 0.137 mm, a breaking 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, this comparative example does not form a total reflection liquid-liquid interface for light, resulting in increased light attenuation.

[0103] Comparative Example 3 (1) preparing hollow aromatic polyamide wet gel fibers from an aromatic polyamide nanofiber dispersion by a coaxial wet spinning method, and preparing hollow aromatic polyamide wet gel fibers by supercritical drying to obtain aromatic polyamide aerogel hollow fibers; (2) fully immersing the aromatic polyamide aerogel hollow fiber obtained in step (1) in deionized water to obtain an aerogel-confined solid-liquid composite hollow fiber as an optical fiber for relevant testing; The core refractive index of the optical fiber obtained in this comparative example is 1.0, the refractive index of the skin is 1.336, the outer diameter is 0.738 mm, the inner diameter (light-transmitting diameter) is 0.464 mm, the thickness of the aerogel skin is 0.137 mm, the breaking strength is 2.2 MPa, the breaking elongation is 32%, and the bending stiffness is 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 the refractive index of the skin layer, and no total reflection liquid-liquid interface of light is formed. Scattering and other losses occur during the transmission process, and light transmission cannot be achieved.

[0104] Comparative Example 4 (1) preparing hollow aromatic polyamide wet gel fibers from an aromatic polyamide nanofiber dispersion by a coaxial wet spinning method, and preparing hollow aromatic polyamide wet gel fibers by supercritical drying to obtain aromatic polyamide aerogel hollow fibers; (2) fully soaking the aromatic polyamide aerogel hollow fiber obtained in step (1) in deionized water to obtain an aerogel-confined solid-liquid composite hollow fiber; (3) Filling the core layer of the aerogel-confined solid-liquid composite hollow fiber prepared in step (2) with perfluoropolyether oil by pressure injection to obtain a liquid-liquid optical fiber based on the aerogel hollow fiber.

[0105] 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-transmitting diameter) of 0.464 mm, an aerogel skin thickness of 0.137 mm, a breaking 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 refractive index of the core layer in this comparative example is smaller than the refractive index of the skin layer, and no total reflection interface of light is formed. Scattering and other losses occur during the transmission process, and light transmission cannot be achieved.

[0106] 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, good bending performance, etc., and the preparation process is simple and easy to carry out large-scale production.

[0107] It should be understood that the order of the various steps or the order in which a particular action is performed is not very important, as long as the teachings of the present invention remain operable. In addition, two or more steps or actions may be performed simultaneously.

[0108] Although the present invention has been described with reference to illustrative embodiments, it will be appreciated by those skilled in the art that various other changes, omissions and / or additions may be made and that elements of the described embodiments may be substituted with substantial equivalents without departing from the spirit and scope of the present invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present invention without departing from the scope of the present invention. Therefore, it is not intended herein to limit the present invention to the specific disclosed embodiments for carrying out the present invention, but rather it is intended that the present invention will include all embodiments within the scope of the appended claims.

Claims

1. A liquid-liquid optical fiber based on aerogel hollow fiber, characterized in that: It includes a core layer and a skin layer covering the core layer, wherein the skin layer includes aerogel hollow fiber and a skin layer liquid, wherein the skin layer liquid infiltrates and fills the porous skeleton of the aerogel hollow fiber to form an aerogel confined solid-liquid composite hollow fiber, and the core layer includes the core layer liquid, and the refractive index of the core layer liquid is greater than the refractive index of the skin layer liquid.

2. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 1, characterized in that: The core layer liquid and the skin layer liquid are immiscible with each other; and / or, the difference between the refractive index of the core layer liquid and the refractive index of the skin layer liquid is 0.0001-1; Preferably, the cortical liquid comprises any one or a combination of two or more of 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; Preferably, the core layer liquid includes any one of 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, carbon disulfide or a combination of two or more thereof.

3. The liquid-liquid optical fiber based on aerogel hollow fiber according to claim 2, characterized in that: The aromatic hydrocarbon organic solvent includes any one of benzene, toluene, xylene, and nitrobenzene, or a combination of two or more thereof; and / or, the aliphatic hydrocarbon organic solvent includes any one of pentane, hexane, octane, tetradecane, and hexadecane, or a combination of two or more thereof; and / or, the alicyclic hydrocarbon organic solvent includes any one of cyclohexane, cyclohexanone, and toluene-cyclohexanone, or a combination of two or more thereof; and / or, the halogenated hydrocarbon organic solvent includes any one of chlorobenzene, dichlorobenzene, dichloromethane, trichloromethane, and tetrachloroethylene, or a combination of two or more thereof; and / or, the alcohol organic solvent includes any one of methanol, ethanol, and isopropanol, or a combination of two or more thereof. and / or, the ether organic solvent includes petroleum ether and / or propylene oxide; and / or, the ester organic solvent includes any one of methyl acetate, ethyl acetate, and propyl acetate, or a combination of two or more thereof; and / or, the ketone organic solvent includes any one of acetone, methyl butyl ketone, and methyl isobutyl ketone, or a combination of two or more thereof; and / or, the diol derivative organic solvent includes any one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether, or a combination of two or more thereof; and / or, the oil liquid includes any one of gasoline, silicone oil, kerosene, mineral oil, oleic acid, and perfluoropolyether oil, or a combination of two or more thereof; And / or, the aerogel hollow fiber includes any one of organic aerogel hollow fiber, inorganic aerogel hollow fiber, organic-inorganic hybrid aerogel hollow fiber, or a combination of two or more thereof; Preferably, the organic aerogel hollow fiber includes any one or a combination of two or more of 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; Preferably, the inorganic aerogel hollow fiber includes any one or a combination of two or more of silica aerogel hollow fiber, titanium oxide aerogel hollow fiber, aluminum oxide 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; Preferably, the organic-inorganic hybrid aerogel hollow fiber is prepared from the organic aerogel hollow fiber and the inorganic aerogel hollow fiber.

4. The liquid-liquid optical fiber based on aerogel hollow fiber according to any one of claims 1 to 3, characterized in that: The liquid-liquid optical fiber based on aerogel hollow fiber has a soft interface based on liquid-liquid; and / or, the interface of the liquid-liquid optical fiber based on aerogel hollow fiber that can realize total internal reflection of light is a liquid-liquid interface with molecular-level roughness; And / or, 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; And / or, 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 is 0.01-100 mm, preferably 0.01-20 mm; And / or, the skin thickness of the liquid-liquid optical fiber based on aerogel hollow fiber is 0.01 to 100 mm, preferably 0.01 to 20 mm; And / or, 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 the transmitted light is 0.01~100 μm, the light transmittance is 1%~100%, and the light attenuation coefficient is 0.001~100 dB / cm.

5. A method for preparing a liquid-liquid optical fiber based on aerogel hollow fiber, characterized in that: include: preparing aerogel hollow fibers; The aerogel hollow fiber is infiltrated with a cortex liquid and filled into the porous skeleton of the aerogel hollow fiber to obtain an aerogel-confined solid-liquid composite hollow fiber as a cortex; The core layer liquid is filled into the solid-liquid composite hollow fiber as the core layer to obtain a liquid-liquid optical fiber based on aerogel hollow fiber, wherein the refractive index of the core layer liquid is greater than the refractive index of the skin layer liquid.

6. The preparation method according to claim 5, characterized in that: include: The spinning solution is subjected to a spinning technique and a drying process to prepare an aerogel hollow fiber; Preferably, the spinning solution includes any one or a combination of two or more of an aromatic polyamide molecular solution, an aromatic polyamide nanofiber solution, a cellulose solution, a cellulose nanofiber dispersion, a sodium alginate solution, a chitosan solution, a polyvinyl alcohol solution, a silk fibroin solution, a polyimide precursor solution, a polyurethane solution, a phenolic precursor solution, a polyurea precursor solution, a polyamide precursor solution, a polyester precursor solution, a polyethylene precursor solution, a polystyrene precursor solution, a polypyrrole precursor solution, a polyvinylidene chloride precursor solution, a silica sol, a titanium oxide precursor solution, an aluminum oxide precursor solution, a zirconium oxide precursor solution, a graphene dispersion, a carbon nanotube dispersion, a metal precursor solution, a carbide precursor solution, and a nitride precursor solution; Preferably, the spinning technology includes using a hollow spinneret or a coaxial needle to form filaments through any one of gel spinning, wet spinning, dry spinning, dry-jet wet spinning, dry freeze spinning, 3D printing, and mold filament forming methods, or a combination of two or more thereof; Preferably, the drying process includes any one or a combination of two or more of supercritical fluid drying, vacuum freeze drying, reduced pressure drying and normal pressure drying.

7. The preparation method according to claim 5, characterized in that: The infiltration time is 1 min to 48 h; And / or, the preparation method comprises: filling the core layer of the solid-liquid composite hollow fiber with a core layer liquid by pressure injection to obtain a liquid-liquid optical fiber based on aerogel hollow fiber; And / or, the core layer liquid and the skin layer liquid are immiscible with each other; and / or, the difference between the refractive index of the core layer liquid and the refractive index of the skin layer liquid is 0.0001-1.

8. The preparation method according to claim 7, characterized in that: The cortical liquid includes any one or a combination of two or more of 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; And / or, the core layer liquid includes any one of 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, carbon disulfide or a combination of two or more thereof; Preferably, the aromatic hydrocarbon organic solvent includes any one of benzene, toluene, xylene, and nitrobenzene, or a combination of two or more thereof; preferably, the aliphatic hydrocarbon organic solvent includes any one of pentane, hexane, octane, tetradecane, and hexadecane, or a combination of two or more thereof; preferably, the alicyclic hydrocarbon organic solvent includes any one of cyclohexane, cyclohexanone, and toluene-cyclohexanone, or a combination of two or more thereof; preferably, the halogenated hydrocarbon organic solvent includes any one of chlorobenzene, dichlorobenzene, dichloromethane, trichloromethane, and tetrachloroethylene, or a combination of two or more thereof; preferably, the alcohol organic solvent includes any one of methanol, ethanol, and isopropanol, or a combination of two or more thereof. Preferably, the ether organic solvent includes petroleum ether and / or propylene oxide; Preferably, the ester organic solvent includes any one of methyl acetate, ethyl acetate, and propyl acetate or a combination of two or more thereof; Preferably, the ketone organic solvent includes any one of acetone, methyl butyl ketone, and methyl isobutyl ketone or a combination of two or more thereof; Preferably, the diol derivative organic solvent includes any one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether or a combination of two or more thereof; Preferably, the oil liquid includes any one of gasoline, silicone oil, kerosene, mineral oil, oleic acid, and perfluoropolyether oil or a combination of two or more thereof.

9. A liquid-liquid optical fiber based on aerogel hollow fiber prepared by the preparation method according to any one of claims 5 to 8.

10. Application of the liquid-liquid optical fiber based on aerogel hollow fiber according to any one of claims 1 to 4 and 9 in the field of optical transmission, optical communication, optical sensing, lighting, Raman spectroscopy or nonlinear optics; preferably, the application includes: The liquid-liquid optical fiber based on aerogel hollow fiber is applied in the fields of underwater optical communication, underwater optical sensing or underwater optical fiber lighting.

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