CN113123018B

CN113123018B - Preparation method of metal oxide nanofiber membrane with flexible reticular vein structure

Info

Publication number: CN113123018B
Application number: CN201911395200.0A
Authority: CN
Inventors: 毛雪; 张庆; 吴月霞; 阳智; 江志威; 洪洁; 赵丽; 刘呈坤; 孙润军
Original assignee: Xian Polytechnic University
Current assignee: Xian Polytechnic University
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2023-01-24
Anticipated expiration: 2039-12-30
Also published as: CN113123018A

Abstract

The invention discloses a preparation method of a flexible reticular vein structure metal oxide nanofiber membrane, which is implemented according to the following steps: step 1, adding at least one metal salt into a corresponding solvent, adding a catalyst while stirring, adding a phosphate blocking agent after stirring, and continuously stirring until the mixture is uniformly mixed to prepare a uniform and stable precursor solution, wherein the dynamic viscosity of the precursor solution is 0.05-5 pas; step 2, performing electrostatic spinning on the precursor solution prepared in the step 1 to prepare precursor reticular vein structure nano-fibers; and step 3: and (3) calcining the precursor reticular vein structure nanofiber prepared in the step (2) in an air atmosphere to prepare the flexible reticular vein structure metal oxide nanofiber membrane. The preparation method of the flexible reticular vein structure metal oxide nanofiber membrane solves the problem of complex preparation process in the prior art.

Description

Preparation method of flexible reticular vein structure metal oxide nanofiber membrane

Technical Field

The invention belongs to the technical field of new material preparation methods, and relates to a preparation method of a flexible reticular vein structure metal oxide nanofiber membrane.

Background

The inorganic fiber is a chemical fiber prepared by taking mineral substances as raw materials, the metal oxide fiber is a typical representative, and the inorganic fiber has the advantages of light weight, high temperature resistance, good thermal stability, low thermal conductivity, small specific heat and the like, and can be widely applied to the fields of filtration, heat insulation, sound absorption, energy, catalysis and the like. The inorganic fiber is nanocrystallized, so that the inorganic fiber has the advantages of high specific surface area, good mechanical stability, small fiber membrane aperture, good fiber continuity and the like, and the application performance of the inorganic fiber is expected to be remarkably improved. At present, the preparation methods of the nanofiber materials are multiple, and electrostatic spinning is one of the main approaches for preparing the nanofiber materials due to the advantages of simple manufacturing equipment, low spinning cost, various types of spinnable raw materials, controllable process and the like. Various metal oxide nano fibers have been developed by utilizing an electrostatic spinning technology, but the fiber prepared at present has a single structure and poor strength, and the application performance cannot be remarkably improved.

Chinese patent "dendritic polyaniline nanofiber and preparation method thereof" (publication No. CN105295039B, publication No. 20180615), preparation and application research of electrospun polyvinylidene fluoride multi-scale dendritic structure nanofiber and preparation and application research of electrospun cellulose dendritic nanofiber (Tianjin university paper) respectively disclose and report a method for preparing dendritic fiber by electrostatic spinning, wherein the prepared nanofiber is a polymer component. In Chinese patent No. CN104120508B (publication No. 20160824) with a hierarchical structure, the metal oxide nanofiber is prepared by an electrostatic spinning-hydrothermal synthesis method, the primary structure of the metal oxide nanofiber is titanium dioxide nanofibers, and the secondary structure of the metal oxide nanofiber is vanadium pentoxide nanoparticles obtained by crystal growth.

According to Chinese patent 'preparation method of flexible fiber membrane-shaped alumina-based catalyst' (publication No. CN106868713B, publication No. 20190301), a flexible fiber membrane is obtained through electrostatic spinning and calcining processes, and the patent needs to add a polymer in the preparation process of the flexible fiber membrane-shaped alumina-based catalyst and has a single structure.

In Chinese patent, CN102557628B and an electrostatic spinning technology are combined to prepare zirconia gel fiber, and the gel fiber is calcined to obtain the yttrium-stabilized zirconia ceramic fiber, however, in the preparation process of the flexible metal oxide fiber film, a polymer needs to be added, and the prepared metal oxide has a single structure, and the application performance of the prepared metal oxide is not remarkably improved.

Disclosure of Invention

The invention aims to provide a preparation method of a flexible reticular vein structure metal oxide nanofiber membrane, which solves the problem of complex preparation process in the prior art.

The technical scheme adopted by the invention is that the preparation method of the flexible reticular vein structure metal oxide nanofiber membrane is implemented according to the following steps:

step 1, adding at least one metal salt into a corresponding solvent, adding a catalyst while stirring, adding a phosphate blocking agent after stirring for 10-60min, continuously stirring for 10-300min, and uniformly mixing to prepare a uniform and stable precursor solution, wherein the dynamic viscosity of the uniform and stable precursor solution is 0.05-5Pa.s; wherein, the ratio of the metal salt to the solvent is 10g, the molar ratio of the metal salt to the catalyst is 1;

step 2, performing electrostatic spinning on the precursor solution prepared in the step 1 to prepare precursor reticular vein structure nano fibers;

and 3, step 3: and (3) calcining the precursor reticular vein structure nanofiber prepared in the step (2) in an air atmosphere to prepare the flexible reticular vein structure metal oxide nanofiber membrane.

Preferably, step 1 is specifically:

step 1.1, adding at least one metal salt into a corresponding solvent, stirring for 10-60min to enable hydrolysis reaction or alcoholysis reaction to occur between the metal salt and the solvent, and adding a catalyst while stirring to form metal hydroxide nano colloidal particles;

step 1.2, adding a phosphate end capping agent into the metal hydroxide nano colloidal particles prepared in the step 1.1, continuously stirring for 10-300min to enable ester groups on the phosphate end capping agent to undergo hydrolysis reaction and be converted into hydroxyl groups, further performing dehydration reaction on the prepared hydroxyl phosphate compounds and the hydroxide nano colloidal particles, enabling the hydroxide nano colloidal particles to be in a free state by utilizing a plurality of hydroxyl phosphate compounds to surround the hydroxide nano colloidal particles through oxygen-bridged bonds, enabling the phosphate ligands to play an end capping role on the nano colloidal particles, inhibiting further agglomeration among the hydroxide nano colloidal particles, and finally preparing free nano colloidal particles with the particle size of 1-50nm to obtain a precursor solution.

Preferably, the metal salt is one or more of metal alkoxide, metal acetylacetone salt, metal organic acid salt, nitrate and chloride;

wherein the metal alkoxide is copper methoxide, calcium methoxide, triethyl gallium, ethoxy germanium, tungsten ethoxide, strontium ethoxide, barium ethoxide, zinc ethoxide, tetraethyl titanate, tetrabutyl titanate, vanadium triethoxy oxide, n-propyl titanate, tetraisopropyl titanate, gallium isopropoxide, titanium methoxide, zirconium ethoxide, tantalum ethoxide, niobium ethoxide, zirconium n-propoxide, tetrabutyl zirconate, aluminum triethoxide or aluminum isopropoxide;

the metal acetylacetone salt is aluminum acetylacetonate, cobalt acetylacetonate, nickel acetylacetonate, manganese acetylacetonate, iron acetylacetonate, vanadyl acetylacetonate, barium acetylacetonate, zirconium acetylacetonate, diisopropyl di (acetylacetonate) titanate, zirconium acetylacetonate or zinc acetylacetonate;

the metal organic acid salt is cobalt oxalate, chromium acetate, copper acetate, zirconium acetate, zinc acetate, calcium acetate, niobium oxalate, ferric amine citrate or molybdenum acetate;

the nitrate is beryllium nitrate, magnesium nitrate, copper nitrate, cobalt nitrate, nickel nitrate, manganese nitrate, aluminum nitrate, zirconyl nitrate, aluminum nitrate nonahydrate, gallium nitrate, chromium nitrate nonahydrate, cobalt nitrate hexahydrate or bismuth nitrate pentahydrate;

the chloride is nickel chloride, manganese chloride, copper chloride, zinc chloride, ferric chloride, cobalt chloride hexahydrate, molybdenum pentachloride, aluminum trichloride, indium chloride, magnesium chloride, aluminum chloride hexahydrate, tributyltin chloride, tin tetrachloride, titanium tetrachloride or bismuth chloride.

Preferably, the catalyst is an acid catalyst or a base catalyst;

wherein, the acid catalyst is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, trichloroacetic acid, sodium bisulfite, formic acid, glacial acetic acid, citric acid and hydrofluoric acid;

the alkali catalyst is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, calcium hydroxide, barium hydroxide, sodium bicarbonate and ammonia water.

Preferably, if the metal salt needs to be hydrolyzed or alcoholyzed at a pH of 1-7, the catalyst is selected from one or more of acid catalysts;

if the metal salt needs to be hydrolyzed or alcoholyzed at a pH of 7-13, the catalyst is selected from one or more alkali catalysts.

Preferably, the solvent is one or more of water, methanol, ethanol, propanol, butanol, ethylene glycol and isopropanol.

Preferably, the phosphate-based capping agent is selected from one or more of methyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, methyl phosphate, diethyl methyl phosphate, di-n-butyl methyl phosphate, dimethyl vinyl phosphate, diethyl ethyl phosphate, diisooctyl phosphate, diethylhexyl phosphate, tris (2-n-butoxyethyl) phosphate, triethyl diphosphate, trioctyl phosphate, di (2-ethylhexyl) phosphate, triisopropyl phosphate, diethyl phosphite, diethyl acetyl phosphite, triisopropyl phosphite, dibutyl phosphite, dimethyl phosphite, diethyl methyl phosphite, trimethyl phosphite, and triethyl phosphite.

Preferably, the electrostatic spinning process in step 2 is as follows: and (3) conveying the precursor solution prepared in the step (1) to a spinneret orifice, and curing to form the precursor reticular vein structure nanofiber, namely the precursor reticular vein structure nanofiber, under the action of a high-voltage electric field.

Preferably, the electrostatic spinning process parameters are: the spinning temperature is 18-35 ℃, the relative humidity is 10-40%, the perfusion speed is 0.2-18mL/h, the spinning distance is 5-40cm, and the spinning voltage is 35-100kV.

Preferably, the calcination process in step 3 is: the calcining temperature is gradually increased from room temperature to 450-1000 ℃, the heating rate is 3-10 ℃/min, and the temperature is kept for 40-250min at the highest temperature.

The invention has the beneficial effects that:

the invention mixes metal salt, solvent, catalyst and phosphate blocking agent uniformly, and prepares uniform and stable precursor solution containing a large amount of 1-50nm free nano colloidal particles by using the blocking effect of the phosphate blocking agent on the metal hydroxide nano colloidal particles. According to the invention, the precursor nanofiber with the reticular vein structure can be obtained without adding an organic high molecular polymer in the precursor solution forming process, and the flexible reticular vein structure metal oxide nanofiber membrane is finally prepared by calcining.

Drawings

Fig. 1 is a micrograph of a flexible reticular vein structure niobium pentoxide nanofiber membrane prepared in example 1 in the preparation method of the flexible reticular vein structure metal oxide nanofiber membrane of the present invention.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The preparation method of the flexible reticular vein structure metal oxide nanofiber membrane is implemented according to the following steps:

step 1, adding at least one metal salt into a corresponding solvent, adding a catalyst while stirring, adding a phosphate blocking agent after stirring for 10-60min, continuously stirring for 10-300min, and uniformly mixing to prepare a uniform and stable precursor solution with the dynamic viscosity of 0.05-5Pa.s; wherein, the ratio of the metal salt to the solvent is 10g, the molar ratio of the metal salt to the catalyst is 1; the method comprises the following specific steps:

step 1.2, adding a phosphate end capping agent into the metal hydroxide nano colloidal particles prepared in the step 1.1, continuously stirring for 10-300min to enable ester groups on the phosphate end capping agent to undergo hydrolysis reaction and be converted into hydroxyl groups, further performing dehydration reaction on the prepared hydroxyl phosphate compounds and the hydroxide nano colloidal particles, enabling the hydroxide nano colloidal particles to be in a free state by utilizing a plurality of hydroxyl phosphate compounds to surround the hydroxide nano colloidal particles through oxygen-bridged bonds, enabling the phosphate ligands to play an end capping role on the nano colloidal particles, inhibiting further agglomeration among the hydroxide nano colloidal particles, and finally preparing free nano colloidal particles with the particle size of 1-50nm to obtain a precursor solution;

step 2, performing electrostatic spinning on the precursor solution prepared in the step 1 to prepare precursor reticular vein structure nano-fibers; wherein the electrostatic spinning process comprises the following steps: and (2) conveying the precursor solution prepared in the step (1) to a spinneret orifice, and curing to form the precursor reticular vein structure nanofiber under the action of a high-voltage electric field, wherein the precursor reticular vein structure nanofiber is obtained by the following electrostatic spinning process parameters: the spinning temperature is 18-35 ℃, the relative humidity is 10-40%, the perfusion speed is 0.2-18mL/h, the spinning distance is 5-40cm, and the spinning voltage is 35-100kV;

and 3, step 3: calcining the precursor reticular vein structure nanofiber prepared in the step 2 in the air atmosphere to prepare the flexible reticular vein structure metal oxide nanofiber membrane, wherein the calcining process comprises the following steps: the calcining temperature is gradually increased from room temperature to 450-1000 ℃, the heating rate is 3-10 ℃/min, and the temperature is kept for 40-250min at the highest temperature.

wherein the metal alkoxide is copper methoxide, calcium methoxide, triethyl gallium, ethoxy germanium, tungsten ethoxide, strontium ethoxide, barium ethoxide, zinc ethoxide, tetraethyl titanate, tetrabutyl titanate, triethoxy vanadium oxide, n-propyl titanate, tetraisopropyl titanate, gallium isopropoxide, titanium methoxide, zirconium ethoxide, tantalum ethoxide, niobium ethoxide, zirconium n-propoxide, tetrabutyl zirconate, aluminum triethoxide or aluminum isopropoxide;

Preferably, the catalyst is an acid catalyst or a base catalyst;

The flexible reticular vein structure metal oxide nanofiber membrane prepared by the method comprises main vein fibers with the diameter range of 20-500nm and side vein fibers with the diameter range of 1-20nm, the relative standard deviation is 1-5%, and the size of crystal grains in the nanofibers is 1-20nm. The reticular vein structure metal oxide nanofiber has a compact structure and good mechanical properties, and the softness of the fiber membrane is 10-120mN and the tensile strength of the fiber membrane is 10-1000MPa according to the GB/T8942-2002 test standard.

According to the invention, the precursor solution has more colloidal particle content, so that the dynamic viscosity of the solution is increased, and the spinnability is enhanced.

In the process of carrying out electrostatic spinning on the precursor solution, the precursor solution is conveyed to a spinneret orifice, liquid drops at a needle head are split into small drops containing free nano colloidal particles under the action of an electric field force under the action of a high-voltage electric field, and the small drops are stretched at a high speed, split and volatilized by a solvent under the action of the electric field force and finally solidified to form the reticular vein structure nano fibers, namely the precursor reticular vein structure nano fibers.

The precursor reticular vein structure nanofiber is calcined in the air atmosphere, so that the flexible reticular vein structure metal oxide nanofiber membrane can be prepared. Because the concentration of the free state nano colloidal particles of 1-50nm in the precursor solution prepared by the invention is higher, the content of the inorganic component in the precursor reticular vein nano fiber obtained by electrostatic spinning of the precursor solution exceeds 95%, in the process of converting the precursor reticular vein nano fiber into the metal oxide nano fiber in the subsequent high-temperature calcination stage, the framework structure of the reticular vein nano fiber cannot be damaged due to the massive decomposition of the organic component, and can be completely reserved. Meanwhile, phosphorus provided by the phosphate blocking agent can partially enter metal oxide crystal lattices, and the mechanical property of the reticular vein metal oxide nano-fiber is further improved by playing the role of stabilizing the crystal form, so that the finally obtained reticular vein metal oxide nano-fiber has good flexibility and tensile strength.

Example 1

A preparation method of a niobium pentoxide nanofiber membrane with a flexible reticular vein structure comprises the following specific steps:

step 1: adding niobium oxalate into water, adding sodium hydroxide while stirring, adding dimethyl methylphosphate after stirring for 25min, and continuously stirring for 35min, wherein the ratio of niobium oxalate to water is 10g to 100mL, the molar ratio of niobium oxalate to sodium hydroxide is 1, the molar ratio of niobium oxalate to dimethyl methylphosphate is 1, and the niobium oxalate to dimethyl methylphosphate are uniformly mixed to prepare a uniform and stable precursor solution with the kinetic viscosity of 1.7Pa · s, wherein the precursor solution contains free nano colloidal particles, and the structural formula of the free nano colloidal particles is as follows:

and 2, step: and (3) carrying out electrostatic spinning on the precursor solution to prepare the precursor reticular vein structure nanofiber. Electrostatic spinning process parameters: the spinning temperature is 25 ℃, the relative humidity is 30%, the perfusion speed is 1.2mL/h, the spinning distance is 18cm, and the spinning voltage is 50kV.

And step 3: and (2) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 950 ℃ from room temperature, the heating rate is 10 ℃/min, and the precursor reticular vein structure nanofiber is kept for 120min at the highest temperature to prepare the flexible reticular vein structure niobium pentoxide nanofiber membrane, a micrograph of the flexible reticular vein structure niobium pentoxide nanofiber membrane is shown in figure 1, the average diameter of main vein fibers of the flexible reticular vein structure niobium pentoxide nanofiber membrane is 220nm, the average diameter of side vein fibers of the flexible reticular vein structure niobium pentoxide nanofiber membrane is 20nm, and relative standard deviations of the flexible reticular vein structure niobium pentoxide nanofiber membrane are respectively 2% and 5%. The grain size in the fiber film is 14nm, and the tensile strength of the fiber film is 160MPa. The niobium pentoxide nanofiber structure is compact, the flexible reticular pulse structure niobium pentoxide nanofiber membrane has good flexibility, and the softness of the fiber membrane is 70mN by referring to GB/T8942-2002 test standards.

Example 2

A preparation method of an aluminum oxide nanofiber membrane with a flexible reticular vein structure comprises the following specific steps:

step 1: adding aluminum nitrate nonahydrate into water, adding hydrochloric acid while stirring, adding triethyl phosphate after stirring for 60min, and continuously stirring for 60min, wherein the proportion of the aluminum nitrate nonahydrate to the water is 10g, the molar ratio of the aluminum nitrate nonahydrate to the hydrochloric acid is 1:

and 2, step: and (3) carrying out electrostatic spinning on the precursor solution to prepare the precursor reticular vein structure nanofiber. Electrostatic spinning process parameters: the spinning temperature is 22 ℃, the relative humidity is 20%, the perfusion speed is 5mL/h, the spinning distance is 28cm, and the spinning voltage is 36kV.

And step 3: and (2) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 1000 ℃ from room temperature, the heating rate is 8 ℃/min, and the precursor reticular vein structure nanofiber is kept for 100min at the highest temperature to obtain the flexible reticular vein structure alumina nanofiber membrane. The average diameter of main vein fibers of the flexible reticular vein structure alumina nanofiber membrane is 380nm, the average diameter of side vein fibers is 18nm, and the relative standard deviation is 1% and 5% respectively. The grain size in the fiber film is 6nm, and the tensile strength is 40MPa. The alumina nanofiber has a compact structure, and the flexible reticular vein structure alumina nanofiber membrane has good flexibility, and the softness of the fiber membrane is 70mN by referring to GB/T8942-2002 test standards.

Example 3

A preparation method of a flexible titanium dioxide nanofiber membrane with a reticular vein structure comprises the following specific steps:

step 1: adding n-propyl titanate into propanol, adding sulfuric acid while stirring, adding dimethyl phosphite after stirring for 60min, and continuously stirring for 105min, wherein the molar ratio of n-propyl titanate to dimethyl phosphite is 1; the proportion of n-propyl ethyl titanate to propanol is 10g, 100mL, the molar ratio of n-propyl titanate to sulfuric acid is 4, and the uniform and stable precursor solution with the dynamic viscosity of 0.9 Pa.s is prepared by uniformly mixing, wherein the precursor solution contains free nano colloidal particles, and the structural formula is as follows:

step 2: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. Electrostatic spinning process parameters: the spinning temperature is 30 ℃, the relative humidity is 20%, the perfusion speed is 1mL/h, the spinning distance is 23cm, and the spinning voltage is 60kV.

And step 3: and (2) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 800 ℃ from room temperature, the heating rate is 6 ℃/min, and the temperature is kept at the highest temperature for 140min to obtain the flexible reticular vein structure titanium dioxide nanofiber membrane. The average diameter of main vein fibers of the flexible reticular vein structure titanium dioxide nanofiber membrane is 540nm, the average diameter of side vein fibers is 13nm, and the relative standard deviation is 2% and 5% respectively. The grain size in the fiber film is 7nm, and the tensile strength is 500MPa. The titanium dioxide nanofiber structure is compact, the flexible reticular vein structure titanium dioxide nanofiber membrane has good flexibility, and the softness of the fiber membrane is 65mN by referring to GB/T8942-2002 test standards.

Example 4

step 1: adding aluminum acetylacetonate into water, adding ammonia water while stirring, adding trimethyl phosphate after stirring for 30min, continuously stirring for 45min, wherein the proportion of the aluminum acetylacetonate to the water is 10g, 70mL, the molar ratio of the aluminum acetylacetonate to the ammonia water is 1.6, the molar ratio of the aluminum acetylacetonate to the trimethyl phosphate is 1.

And 2, step: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. Electrostatic spinning process parameters: the spinning temperature is 35 ℃, the relative humidity is 20%, the perfusion speed is 1.5mL/h, the spinning distance is 30cm, and the spinning voltage is 100kV.

And 3, step 3: and (2) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 600 ℃ from room temperature, the heating rate is 3 ℃/min, and the precursor reticular vein structure nanofiber is kept for 50min at the highest temperature to obtain the flexible reticular vein structure alumina nanofiber membrane. The average diameter of main vein fibers of the flexible reticular vein structure alumina nanofiber membrane is 500nm, the average diameter of side vein fibers is 18nm, and the relative standard deviation is 2% and 4% respectively. The grain size in the fiber film is 14nm, and the tensile strength is 305MPa. The alumina nanofiber has a compact structure, the alumina nanofiber membrane with the flexible reticular vein structure has good flexibility, and the softness of the fiber membrane is 50mN by referring to GB/T8942-2002 test standards.

Example 5

A preparation method of a flexible reticular vein structure zirconia nanofiber membrane comprises the following specific steps:

step 1: adding zirconium acetate and calcium acetate into water, adding ammonia water while stirring, adding dimethyl methyl phosphate after stirring for 60min, and continuously stirring for 105min, wherein the molar ratio of zirconium acetate to calcium acetate is 97:3, the molar ratio of the total of zirconium acetate and calcium acetate to dimethyl methylphosphate is 1; the proportion of zirconium acetate, calcium acetate and water is 10g, the molar ratio of zirconium acetate, calcium acetate and ammonia water is 1:0.5, and the zirconium acetate, the calcium acetate and the ammonia water are uniformly mixed to prepare a uniform and stable precursor solution with the dynamic viscosity of 0.8Pa · s, wherein the precursor solution contains free nano colloidal particles.

Step 2: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. Electrostatic spinning process parameters: the spinning temperature is 25 ℃, the relative humidity is 10%, the perfusion speed is 1.2mL/h, the spinning distance is 22cm, and the spinning voltage is 80kV.

And 3, step 3: and (3) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 900 ℃ from room temperature, the heating rate is 9 ℃/min, and the precursor reticular vein structure nanofiber is kept for 180min at the highest temperature to obtain the flexible reticular vein structure zirconium oxide calcium nanofiber membrane. The average diameter of main vein fibers of the flexible reticular vein structure zirconium oxide calcium nanofiber membrane is 450nm, the average diameter of side vein fibers is 17nm, and the relative standard deviation is 1% and 5% respectively. The grain size in the fiber film is 17nm, and the tensile strength is 500MPa. The calcium zirconium oxide nanofiber has a compact structure, and the calcium zirconium oxide nanofiber membrane with the flexible reticular vein structure has good flexibility, and the softness of the fiber membrane is 65mN by referring to GB/T8942-2002 test standards.

Example 6

A preparation method of a flexible reticular vein structure magnesium oxide nanofiber membrane comprises the following specific steps:

step 1: adding magnesium nitrate into water, adding ammonia water while stirring, adding triethyl phosphate after stirring for 60min, and continuously stirring for 120min, wherein the ratio of the magnesium nitrate to the water is 10g to 70mL, the molar ratio of the magnesium nitrate to the ammonia water is 1.

And 2, step: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. The electrostatic spinning process parameters are as follows: the spinning temperature is 23 ℃, the relative humidity is 25%, the perfusion speed is 1.1mL/h, the spinning distance is 10cm, and the spinning voltage is 35kV.

And 3, step 3: and (2) calcining the precursor nano-fiber with the reticular vein structure in an air atmosphere, wherein the calcining temperature is gradually increased to 700 ℃ from room temperature, the heating rate is 5 ℃/min, and the temperature is kept for 60min at the highest temperature, so that the flexible reticular vein structure magnesium oxide nano-fiber film is prepared. The average diameter of main vein fibers of the magnesium oxide nanofiber membrane with the flexible reticular vein structure is 476nm, the average diameter of side vein fibers of the magnesium oxide nanofiber membrane is 20nm, and the relative standard deviation is 1 percent and 4 percent respectively. The grain size in the fiber film is 17nm, and the tensile strength is 430MPa. The magnesium oxide nanofiber has a compact structure, and the magnesium oxide nanofiber membrane with the flexible reticular vein structure has good flexibility, and the softness of the fiber membrane is 55mN by referring to GB/T8942-2002 test standards.

Example 7

A preparation method of a flexible reticular vein structure magnesium oxide-aluminum oxide nanofiber membrane comprises the following specific steps:

step 1: adding magnesium chloride and aluminum chloride hexahydrate into water, adding glacial acetic acid while stirring, adding dimethyl phosphite after stirring for 60min, and continuously stirring for 130min, wherein the ratio of the magnesium chloride and the aluminum chloride hexahydrate to the water is 10g/80mL, the molar ratio of the magnesium chloride to the aluminum chloride hexahydrate is 1: and 2, uniformly mixing the magnesium chloride, the aluminum chloride hexahydrate and the glacial acetic acid in a molar ratio of 1.

And 2, step: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. Electrostatic spinning process parameters: the spinning temperature is 23 ℃, the relative humidity is 30%, the perfusion speed is 1.0mL/h, the spinning distance is 13cm, and the spinning voltage is 40kV.

And step 3: and (2) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 1000 ℃ from room temperature, the heating rate is 10 ℃/min, and the precursor reticular vein structure nanofiber is kept for 120min at the highest temperature to obtain the flexible reticular vein structure magnesium oxide-aluminum oxide nanofiber membrane. The average diameter of main vein fibers of the magnesium oxide-aluminum oxide nanofiber membrane with the flexible reticular vein structure is 240nm, the average diameter of side vein fibers is 20nm, and the relative standard deviation is 2% and 3% respectively. The grain size in the fiber film is 13nm, and the tensile strength is 500MPa. The magnesium oxide-aluminum oxide nanofiber has a compact structure, and the magnesium oxide-aluminum oxide nanofiber membrane with a flexible reticular vein structure has good flexibility, and the softness of the fiber membrane is 60mN by referring to GB/T8942-2002 test standards.

Example 8

A preparation method of a flexible network vein structure zirconium dioxide nanofiber membrane comprises the following specific steps:

step 1: adding zirconium n-propoxide into isopropanol, adding sodium bicarbonate while stirring, adding triethyl phosphate after stirring for 15min, and continuously stirring for 25min, wherein the ratio of zirconium n-propoxide to isopropanol is 10g.

Step 2: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. Electrostatic spinning process parameters: the spinning temperature is 20 ℃, the relative humidity is 15%, the perfusion speed is 1.5mL/h, the spinning distance is 20cm, and the spinning voltage is 35kV.

And step 3: and (2) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 1000 ℃ from room temperature, the heating rate is 5 ℃/min, and the precursor reticular vein structure nanofiber is kept for 120min at the highest temperature to obtain the flexible reticular vein structure zirconium dioxide nanofiber membrane. The average diameter of main vein fibers of the flexible reticular vein structure zirconium dioxide nanofiber membrane is 130nm, the average diameter of side vein fibers is 10nm, and the relative standard deviation is 1% and 5% respectively. The grain size in the fiber film is 10nm, and the tensile strength is 100MPa. The zirconium dioxide nanofiber has a compact structure, and the zirconium dioxide nanofiber membrane with the flexible reticular vein structure has good flexibility, and the softness of the fiber membrane is 50mN by referring to GB/T8942-2002 test standards.

Example 9

A preparation method of a flexible reticular vein structure titanium dioxide nanofiber membrane comprises the following specific steps:

step 1: adding isopropyl titanate into propanol, adding sodium carbonate while stirring, adding diethyl acetyl phosphite after stirring for 20min, continuously stirring for 45min, wherein the proportion of isopropyl titanate to propanol is 10g, the molar ratio of isopropyl titanate to sodium carbonate is 1.

Step 2: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. The electrostatic spinning process parameters are as follows: the spinning temperature is 18 ℃, the relative humidity is 23%, the perfusion speed is 1.0mL/h, the spinning distance is 15cm, and the spinning voltage is 35kV.

And step 3: and (2) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 800 ℃ from room temperature, the heating rate is 3 ℃/min, and the precursor reticular vein structure nanofiber is kept for 60min at the highest temperature to obtain the flexible reticular vein structure titanium dioxide nanofiber membrane. The average diameter of main vein fibers of the flexible reticular vein structure titanium dioxide nanofiber membrane is 210nm, the average diameter of side vein fibers is 19nm, and the relative standard deviation is 1% and 4% respectively. The grain size in the fiber film is 17nm, and the tensile strength is 10MPa. The titanium dioxide nanofiber structure is compact, the flexible reticular vein structure titanium dioxide nanofiber membrane has good flexibility, and the softness of the fiber membrane is 40mN by referring to GB/T8942-2002 test standards.

Example 10

A preparation method of a ferroferric oxide nanofiber membrane with a flexible reticular vein structure comprises the following specific steps:

step 1: adding ferric acetylacetonate into ethanol, adding sodium bicarbonate while stirring, adding dimethyl methylphosphate after stirring for 60min, continuously stirring for 100min, wherein the proportion of ferric acetylacetonate to ethanol is 10g.

And 2, step: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. The electrostatic spinning process parameters are as follows: the spinning temperature is 22 ℃, the relative humidity is 30%, the perfusion speed is 0.2mL/h, the spinning distance is 40cm, and the spinning voltage is 35kV.

And 3, step 3: and (3) calcining the precursor network vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 600 ℃ from room temperature, the heating rate is 5 ℃/min, and the precursor network vein structure nanofiber is kept at the highest temperature for 40min to obtain the flexible network vein structure ferroferric oxide nanofiber membrane. The average diameter of main vein fibers of the ferroferric oxide nanofiber membrane with the flexible reticular vein structure is 270nm, the average diameter of side vein fibers is 15nm, and the relative standard deviation is 2% and 3% respectively. The grain size in the fiber film is 10nm, and the tensile strength is 80MPa. The ferroferric oxide nanofiber has a compact structure, and the ferroferric oxide nanofiber membrane with a flexible reticular vein structure has good flexibility, and the softness of the fiber membrane is 30mN by referring to GB/T8942-2002 test standards.

Example 11

A preparation method of a flexible reticular vein structure tin oxide nanofiber membrane comprises the following specific steps:

step 1: adding tributyltin chloride into ethanol, adding glacial acetic acid while stirring, adding diethyl phosphite after stirring for 30min, continuously stirring for 45min, wherein the ratio of 2 tributyltin chloride to ethanol is 10g to 70mL, the molar ratio of tributyltin chloride to glacial acetic acid is 1.

Step 2: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. The electrostatic spinning process parameters are as follows: the spinning temperature is 21 ℃, the relative humidity is 27%, the perfusion speed is 18mL/h, the spinning distance is 15cm, and the spinning voltage is 80kV.

And step 3: and (2) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 700 ℃ from room temperature, the heating rate is 5 ℃/min, and the temperature is kept for 80min at the highest temperature to obtain the flexible reticular vein structure tin oxide nanofiber membrane. The average diameter of main vein fibers of the flexible reticular vein structure tin oxide nanofiber membrane is 220nm, the average diameter of side vein fibers is 20nm, and the relative standard deviation is 1% and 4% respectively. The grain size in the fiber film is 16nm, and the tensile strength is 50MPa. The tin oxide nanofiber has a compact structure, and the flexible net-like vein structure tin oxide nanofiber membrane has good flexibility, and the softness of the fiber membrane is 80mN by referring to GB/T8942-2002 test standards.

Example 12

A preparation method of a flexible netted vein structure gallium oxide nanofiber membrane comprises the following specific steps:

step 1: adding gallium isopropoxide into ethanol, adding sodium carbonate while stirring, adding dibutyl phosphite after stirring for 40min, continuously stirring for 40min, wherein the proportion of the gallium isopropoxide to the ethanol is 10g.

Step 2: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. The electrostatic spinning process parameters are as follows: the spinning temperature is 26 ℃, the relative humidity is 36%, the perfusion speed is 1.5mL/h, the spinning distance is 15cm, and the spinning voltage is 35kV.

And step 3: and (3) calcining the precursor nano-fiber with the reticular vein structure in an air atmosphere, wherein the calcining temperature is gradually increased to 800 ℃ from room temperature, the heating rate is 3 ℃/min, and the precursor nano-fiber with the reticular vein structure is kept for 40min at the highest temperature to obtain the flexible gallium oxide nano-fiber film with the reticular vein structure. The average diameter of main vein fibers of the flexible reticular vein structure gallium oxide nanofiber membrane is 370nm, the average diameter of side vein fibers is 19nm, and the relative standard deviation is 1% and 4% respectively. The grain size in the fiber film is 16nm, and the tensile strength is 115MPa. The gallium oxide nanofiber has a compact structure, the flexible reticular vein structure gallium oxide nanofiber membrane has good flexibility, and the softness of the fiber membrane is 40mN by referring to GB/T8942-2002 test standards.

Example 13

step 1: dissolving aluminum acetylacetonate and zirconium acetylacetonate in isopropanol, adding sulfuric acid while stirring, adding dimethyl methyl phosphate after stirring for 30min, and continuously stirring for 100min, wherein the molar ratio of aluminum acetylacetonate to zirconium acetylacetonate is 100.

Step 2: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. The electrostatic spinning process parameters are as follows: the spinning temperature is 23 ℃, the relative humidity is 20%, the perfusion speed is 1.5mL/h, the spinning distance is 15cm, and the spinning voltage is 60kV.

And 3, step 3: and (2) calcining the precursor nano-fiber with the net-like vein structure in an air atmosphere, wherein the calcining temperature is gradually increased to 800 ℃ from room temperature, the heating rate is 8 ℃/min, and the temperature is kept for 120min at the highest temperature, so that the flexible aluminum oxide nano-fiber film with the net-like vein structure is prepared. The average diameter of main vein fibers of the flexible reticular vein structure aluminum oxide nanofiber membrane is 280nm, the average diameter of side vein fibers is 20nm, and the relative standard deviation is 1% and 4% respectively. The grain size in the fiber film is 5nm, and the tensile strength is 150MPa. The alumina nanofiber has a compact structure, the flexible reticular vein structure alumina nanofiber membrane has good flexibility, and the softness of the fiber membrane is 10mN by referring to GB/T8942-2002 test standards.

Example 14

A preparation method of a flexible reticular vein structure niobium oxide nanofiber membrane comprises the following specific steps:

step 1: adding niobium oxalate and tin tetrachloride into water, adding glacial acetic acid while stirring, adding ethyl diethyl phosphate after stirring for 60min, and continuously stirring for 30min, wherein the molar ratio of niobium oxalate to tin tetrachloride is 100, the ratio of niobium oxalate to tin tetrachloride to water is 10g.

Step 2: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. The electrostatic spinning process parameters are as follows: the spinning temperature is 24 ℃, the relative humidity is 34%, the perfusion speed is 0.9mL/h, the spinning distance is 15cm, and the spinning voltage is 35kV;

and step 3: and (3) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 1000 ℃ from room temperature, the heating rate is 6 ℃/min, and the precursor reticular vein structure nanofiber is kept for 120min at the highest temperature to obtain the flexible reticular vein structure niobium oxide nanofiber membrane. The average diameter of main vein fibers of the flexible reticular vein structure niobium oxide nanofiber membrane is 420nm, the average diameter of side vein fibers is 15nm, and the relative standard deviation is 1% and 4% respectively. The grain size in the fiber film is 6nm, and the tensile strength is 325MPa. The niobium oxide nanofiber has a compact structure, and the flexible reticular vein structure niobium oxide nanofiber membrane has good flexibility, and the softness of the fiber membrane is 30mN by referring to GB/T8942-2002 test standards.

Example 15

A preparation method of a flexible reticular vein structure copper oxide nanofiber membrane comprises the following specific steps:

step 1: adding copper nitrate and ferric chloride into ethanol, adding sodium bicarbonate while stirring, adding triisopropyl phosphite after stirring for 40min, and continuously stirring for 20min, wherein the molar ratio of the copper nitrate to the ferric chloride is 100.

Step 2: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. Electrostatic spinning process parameters: the spinning temperature is 20 ℃, the relative humidity is 35%, the perfusion speed is 10mL/h, the spinning distance is 25cm, and the spinning voltage is 45kV.

And 3, step 3: and (2) calcining the precursor copper oxide nanofiber with the reticular vein structure in an air atmosphere, wherein the calcining temperature is gradually increased to 900 ℃ from room temperature, the heating rate is 9 ℃/min, and the precursor copper oxide nanofiber is kept for 50min at the highest temperature to obtain the flexible copper oxide nanofiber membrane with the reticular vein structure. The average diameter of main vein fibers of the copper oxide nanofiber membrane with the flexible reticular vein structure is 340nm, the average diameter of side vein fibers is 16nm, and the relative standard deviation is 1% and 5% respectively. The grain size in the fiber film is 2nm, and the tensile strength is 425MPa. The copper oxide nanofiber has a compact structure, the copper oxide nanofiber film with the flexible reticular vein structure has good flexibility, and the softness of the fiber film is 75mN by referring to GB/T8942-2002 test standards.

Example 16

A preparation method of a flexible reticular vein structure ferric oxide nanofiber membrane comprises the following specific steps:

step 1: adding ferric ammonium citrate into water, adding sodium carbonate while stirring, adding triethyl phosphite after stirring for 55min, and continuously stirring for 20min, wherein the proportion of ferric ammonium citrate to water is 10g.

And 2, step: and (3) preparing the precursor solution into the precursor reticular vein structure nanofiber through an electrostatic spinning process. The electrostatic spinning process parameters are as follows: the spinning temperature is 20 ℃, the relative humidity is 25%, the perfusion speed is 13mL/h, the spinning distance is 18cm, and the spinning voltage is 38kV.

And step 3: and (2) calcining the precursor nano-fiber with the reticular vein structure in an air atmosphere, wherein the calcining temperature is gradually increased to 700 ℃ from room temperature, the heating rate is 3 ℃/min, and the temperature is kept for 90min at the highest temperature, so that the flexible iron oxide nano-fiber film with the reticular vein structure is prepared. The average diameter of main vein fibers of the flexible reticular vein structure iron oxide nanofiber membrane is 370nm, the average diameter of side vein fibers is 20nm, and the relative standard deviation is 3% and 4% respectively. The grain size in the fiber film is 19nm, and the tensile strength is 200MPa. The iron oxide nanofiber has a compact structure, the iron oxide nanofiber membrane with the flexible reticular vein structure has good flexibility, and the softness of the fiber membrane is 80mN by referring to GB/T8942-2002 test standards.

Example 17

step 1: adding tetrabutyl titanate into n-butyl alcohol, adding sodium bicarbonate while stirring, adding diethyl acetyl phosphite after stirring for 15min, and continuously stirring for 20min, wherein the ratio of tetrabutyl titanate to n-butyl alcohol is 10g.

Step 2: and (3) carrying out electrostatic spinning on the precursor solution to prepare the precursor reticular vein structure nanofiber. The electrostatic spinning process parameters are as follows: the spinning temperature is 18 ℃, the relative humidity is 23%, the perfusion speed is 3.0mL/h, the spinning distance is 20cm, and the spinning voltage is 35kV.

And step 3: and (2) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 600 ℃ from room temperature, the heating rate is 4 ℃/min, and the temperature is kept at the highest temperature for 70min to obtain the flexible reticular vein structure titanium dioxide nanofiber membrane. The average diameter of main vein fibers of the flexible reticular vein structure titanium dioxide nanofiber membrane is 230nm, the average diameter of side vein fibers is 6nm, and the relative standard deviation is 1% and 4% respectively. The grain size in the fiber film is 1nm, and the tensile strength is 100MPa. The titanium dioxide nanofiber structure is compact, the flexible reticular vein structure titanium dioxide nanofiber membrane has good flexibility, and the softness of the fiber membrane is 60mN by referring to GB/T8942-2002 test standards.

Example 18

step 1: adding zirconium acetate into water, adding sodium hydroxide while stirring, adding triethyl phosphite after stirring for 22min, and continuously stirring for 30min, wherein the ratio of zirconium acetate to water is 10g to 70mL, the molar ratio of zirconium acetate to sodium hydroxide is 1.

Step 2: and (3) carrying out electrostatic spinning on the precursor solution to prepare the precursor reticular vein structure nanofiber. The electrostatic spinning process parameters are as follows: the spinning temperature is 22 ℃, the relative humidity is 20%, the perfusion speed is 3.5mL/h, the spinning distance is 5cm, and the spinning voltage is 35kV.

And step 3: and (3) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 650 ℃ from room temperature, the heating rate is 3 ℃/min, and the precursor reticular vein structure nanofiber is kept for 80min at the highest temperature to obtain the flexible reticular vein structure zirconium oxide nanofiber membrane. The mean diameter of main vein fibers of the flexible reticular vein structure zirconia nanofiber membrane is 500nm, the mean diameter of side vein fibers is 19nm, and the relative standard deviation is 1% and 3% respectively. The grain size in the fiber film is 14nm, and the tensile strength is 1000MPa. The zirconia nanofiber has a compact structure, and the flexible reticular vein structure zirconia nanofiber membrane has good flexibility, and the softness of the fiber membrane is 90mN by referring to GB/T8942-2002 test standards.

Example 19

step 1: adding tin tetrachloride into isobutanol, adding sodium carbonate while stirring, adding dimethyl phosphite after stirring for 30min, continuously stirring for 60min, wherein the ratio of tin tetrachloride to isobutanol is 10g.

And 2, step: and (3) carrying out electrostatic spinning on the precursor solution to prepare the precursor reticular vein structure nanofiber. The electrostatic spinning process parameters are as follows: the spinning temperature is 27 ℃, the relative humidity is 20%, the perfusion speed is 2.5mL/h, the spinning distance is 20cm, and the spinning voltage is 45kV.

And step 3: and (2) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased from room temperature to 750 ℃, the heating rate is 3 ℃/min, and the precursor reticular vein structure nanofiber is kept for 60min at the highest temperature to obtain the flexible reticular vein structure tin oxide nanofiber membrane. The average diameter of main vein fibers of the tin oxide nanofiber membrane with the flexible reticular vein structure is 340nm, the average diameter of side vein fibers is 18nm, and the relative standard deviation is 1% and 3% respectively. The grain size in the fiber film is 15nm, and the tensile strength is 150MPa. The tin oxide nanofiber has a compact structure, and the flexible net-like vein structure tin oxide nanofiber membrane has good flexibility, and the softness of the fiber membrane is 70mN by referring to GB/T8942-2002 test standards.

Example 20

step 1: adding aluminum chloride hexahydrate into ethanol, adding hydrochloric acid while stirring, adding dimethyl phosphite after stirring for 60min, and continuously stirring for 50min, wherein the ratio of the aluminum chloride hexahydrate to the ethanol is 10g.

Step 2: and (3) carrying out electrostatic spinning on the precursor solution to prepare the precursor reticular vein structure nanofiber. The electrostatic spinning process parameters are as follows: the spinning temperature is 25 ℃, the relative humidity is 30%, the perfusion speed is 5.0mL/h, the spinning distance is 30cm, and the spinning voltage is 60kV.

And step 3: and (3) calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased from room temperature to 700 ℃, the heating rate is 4 ℃/min, and the precursor reticular vein structure nanofiber is kept for 45min at the highest temperature to obtain the flexible reticular vein structure alumina nanofiber membrane. The average diameter of main vein fibers of the flexible reticular vein structure alumina nanofiber membrane is 400nm, the average diameter of side vein fibers is 20nm, and the relative standard deviation is 1% and 4% respectively. The grain size in the fiber film is 20nm, and the tensile strength is 230MPa. The alumina nanofiber has a compact structure, and the flexible reticular vein structure alumina nanofiber membrane has good flexibility, and the softness of the fiber membrane is 60mN by referring to GB/T8942-2002 test standards.

Example 21

step 1: adding gallium nitrate into water, adding sodium hydroxide while stirring, adding dibutyl phosphite after stirring for 45min, continuously stirring for 10min, wherein the proportion of gallium nitrate to water is 10g.

Step 2: and (3) performing electrostatic spinning on the precursor solution to prepare the precursor reticular vein structure nanofiber. The electrostatic spinning process parameters are as follows: the spinning temperature is 25 ℃, the relative humidity is 20%, the perfusion speed is 3.0mL/h, the spinning distance is 33cm, and the spinning voltage is 80kV.

And step 3: and (3) calcining the precursor nano-fiber with the reticular vein structure in an air atmosphere, wherein the calcining temperature is gradually increased from room temperature to 870 ℃, the heating rate is 10 ℃/min, and the precursor nano-fiber with the reticular vein structure is kept for 65min at the highest temperature to obtain the flexible gallium oxide nano-fiber film with the reticular vein structure. The average diameter of main vein fibers of the flexible reticular vein structure gallium oxide nanofiber membrane is 240nm, the average diameter of side vein fibers is 18nm, and the relative standard deviation is 1% and 4% respectively. The grain size in the fiber film is 16nm, and the tensile strength is 340MPa. The gallium oxide nanofiber has a compact structure, the flexible reticular vein structure gallium oxide nanofiber membrane has good flexibility, and the softness of the fiber membrane is 120mN by referring to GB/T8942-2002 test standards.

Example 22

A preparation method of a flexible reticular vein structure titanium oxide nanofiber membrane comprises the following specific steps:

step 1: adding titanium tetrachloride into ethanol, adding sodium bicarbonate while stirring, adding triethyl phosphite after stirring for 60min, and continuously stirring for 30min, wherein the ratio of titanium tetrachloride to ethanol is 10g to 200mL, the molar ratio of titanium tetrachloride to sodium bicarbonate is 1.

And 2, step: and (3) carrying out electrostatic spinning on the precursor solution to prepare the precursor reticular vein structure nanofiber. The electrostatic spinning process parameters are as follows: the spinning temperature is 23 ℃, the relative humidity is 30%, the perfusion speed is 4.0mL/h, the spinning distance is 20cm, and the spinning voltage is 50kV.

And step 3: and (3) calcining the precursor titanium oxide nanofiber with the reticular vein structure in an air atmosphere, wherein the calcining temperature is gradually increased from room temperature to 750 ℃, the heating rate is 8 ℃/min, and the precursor titanium oxide nanofiber with the reticular vein structure is kept for 60min at the highest temperature to obtain the flexible titanium oxide nanofiber membrane with the reticular vein structure. The average diameter of main vein fibers of the flexible reticular vein structure titanium oxide nanofiber membrane is 350nm, the average diameter of side vein fibers is 16nm, and the relative standard deviation is 1% and 5% respectively. The grain size in the fiber film is 10nm, and the tensile strength is 300MPa. The titanium oxide nanofiber has a compact structure, and the flexible reticular vein structure titanium oxide nanofiber membrane has good flexibility, and the softness of the fiber membrane is 30mN by referring to GB/T8942-2002 test standards.

Example 23

step 1: adding ferric chloride into water, adding sodium bicarbonate while stirring, adding triethyl phosphite after stirring for 15min, and continuously stirring for 35min, wherein the proportion of ferric chloride to water is 10g, 60mL, the molar ratio of ferric chloride to hydrochloric acid is 1.

And 2, step: and (3) performing electrostatic spinning on the precursor solution to prepare the precursor reticular vein structure nanofiber. The electrostatic spinning process parameters are as follows: the spinning temperature is 23 ℃, the relative humidity is 30%, the perfusion speed is 8.0mL/h, the spinning distance is 20cm, and the spinning voltage is 45kV.

And step 3: and (3) calcining the precursor network vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased from room temperature to 750 ℃, the heating rate is 8 ℃/min, and the precursor network vein structure nanofiber is kept for 250min at the highest temperature to obtain the flexible network vein structure ferroferric oxide nanofiber membrane. The average diameter of main vein fibers of the ferroferric oxide nanofiber membrane with the flexible reticular vein structure is 260nm, the average diameter of side vein fibers is 17nm, and the relative standard deviation is 2% and 4% respectively. The grain size in the fiber film is 15nm, and the tensile strength is 10MPa. The ferroferric oxide nanofiber has a compact structure, and the ferroferric oxide nanofiber membrane with a flexible reticular vein structure has good flexibility, and the softness of the fiber membrane is 50mN by referring to GB/T8942-2002 test standards.

Example 24

step 1: adding zirconyl nitrate into water/ethanol, adding sodium hydroxide while stirring, adding triethyl phosphite after stirring for 15min, and continuously stirring for 45min, wherein the ratio of zirconyl nitrate to water/ethanol is 10g 70mL, the volume ratio of water/ethanol is 4.

Step 2: and (3) carrying out electrostatic spinning on the precursor solution to prepare the precursor reticular vein structure nanofiber. The electrostatic spinning process parameters are as follows: the spinning temperature is 20 ℃, the relative humidity is 40%, the perfusion speed is 1.0mL/h, the spinning distance is 16cm, and the spinning voltage is 35kV.

And step 3: and calcining the precursor reticular vein structure nanofiber in an air atmosphere, wherein the calcining temperature is gradually increased to 450 ℃ from room temperature, the heating rate is 5 ℃/min, and the temperature is kept for 230min at the highest temperature to prepare the flexible reticular vein structure zirconium oxide nanofiber membrane. The average diameter of main vein fibers of the flexible reticular vein structure zirconium oxide nanofiber membrane is 240nm, the average diameter of side vein fibers is 20nm, and the relative standard deviation is 1% and 4% respectively. The grain size in the fiber film is 10nm, and the tensile strength of the fiber film is 100MPa. The zirconia nanofiber has a compact structure, and the flexible reticular vein structure zirconia nanofiber membrane has good flexibility, and the softness of the fiber membrane is 50mN by referring to GB/T8942-2002 test standards.

Claims

1. The preparation method of the flexible reticular vein structure metal oxide nanofiber membrane is characterized by comprising the following steps:

step 1, adding at least one metal salt into a corresponding solvent, adding a catalyst while stirring, adding a phosphate blocking agent after stirring for 10-60min, continuously stirring for 10-300min, and uniformly mixing to prepare a uniform and stable precursor solution, wherein the dynamic viscosity of the uniform and stable precursor solution is 0.05-5Pa.s; wherein, the ratio of the metal salt to the solvent is 10g, the molar ratio of the metal salt to the catalyst is 1; the method comprises the following specific steps:

step 2, performing electrostatic spinning on the precursor solution prepared in the step 1 to prepare precursor reticular vein structure nano fibers; the electrostatic spinning process comprises the following steps: and (2) conveying the precursor solution prepared in the step (1) to a spinneret orifice, and solidifying the precursor solution to form the precursor nano-fibers with the reticular vein structure under the action of a high-voltage electric field, wherein the precursor nano-fibers with the reticular vein structure are obtained by the electrostatic spinning process with the parameters as follows: the spinning temperature is 18-35 ℃, the relative humidity is 10-40%, the perfusion speed is 0.2-18mL/h, the spinning distance is 5-40cm, and the spinning voltage is 35-100kV;

and step 3: calcining the precursor reticular vein structure nanofiber prepared in the step 2 in an air atmosphere to prepare a flexible reticular vein structure metal oxide nanofiber membrane; the calcining process comprises the following steps: the calcining temperature is gradually increased from room temperature to 450-1000 ℃, the heating rate is 3-10 ℃ per min, and the calcining temperature is kept at the highest temperature for 40-250min.

2. The method for preparing the metal oxide nanofiber membrane with the flexible reticular vein structure according to claim 1, wherein the metal salt is one or more of metal alkoxide, metal acetylacetone salt, metal organic acid salt, nitrate and chloride;

the metal acetylacetone salt is aluminum acetylacetonate, cobalt acetylacetonate, nickel acetylacetonate, manganese acetylacetonate, iron acetylacetonate, vanadyl acetylacetonate, barium acetylacetonate, zirconium acetylacetonate, diisopropyl di (acetylacetonate) titanate, zirconium acetylacetonate, or zinc acetylacetonate;

3. The method for preparing the flexible reticular vein structure metal oxide nanofiber membrane as claimed in claim 1, wherein the catalyst is an acid catalyst or a base catalyst;

the alkali catalyst is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, calcium hydroxide, barium hydroxide, sodium bicarbonate and ammonia water.

4. The method for preparing the flexible reticular metallic oxide nanofiber membrane as claimed in claim 3, wherein if the metallic salt is a metallic salt which needs to be hydrolyzed or alcoholyzed under the condition of pH 1-7, the catalyst is selected from one or more of acid catalysts;

if the metal salt is a metal salt which needs to be hydrolyzed or alcoholyzed at a pH of 7-13, the catalyst is selected from one or more of alkali catalysts.

5. The method for preparing the flexible reticular vein structure metal oxide nanofiber membrane as claimed in claim 1, wherein the solvent is one or more of water, methanol, ethanol, propanol, butanol, ethylene glycol and isopropanol.

6. The method as claimed in claim 1, wherein the phosphate capping reagent is selected from one or more of methyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, methyl phosphate, diethyl methyl phosphate, di-n-butyl methyl phosphate, dimethyl vinyl phosphate, diethyl ethyl phosphate, diisooctyl phosphate, diethylhexyl phosphate, tris (2-n-butoxyethyl) phosphate, triethyl diphosphate, trioctyl phosphate, bis (2-ethylhexyl) phosphate, triisopropyl phosphate, diethyl phosphite, diethyl acetyl phosphite, triisopropyl phosphite, dibutyl phosphite, dimethyl phosphite, diethyl methyl phosphite, trimethyl phosphite or triethyl phosphite.