Preparation method of electrostatic spinning film material compounded by mesoporous silica nanoprobe

Abstract

The invention discloses a preparation method of a mesoporous silica nanoprobe compounded electrostatic spinning film material, and belongs to the technical field of fluorescent sensing materials. Organic fluorescent molecules are modified on the surface of mesoporous silica in a gradual synthesis mode, silica nanoparticles capable of sensing H2S are prepared, and then the silica nanoparticles are wrapped with PAN (polyacrylonitrile) and PVP (polyvinylpyrrolidone) matrixes in an electrostatic spinning mode. The sensor not only maintains the specific fluorescent recognition characteristic of fluorescent molecules to H2S, but also combines the protection effects of a mesoporous silica skeleton and PAN and PVP matrixes, and obtains a fluorescent sensing film with excellent performance.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent sensing materials technology, and more specifically relates to a method for preparing an electrospun thin film material composed of mesoporous silica nanoprobes. Background Technology

[0002] Hydrogen sulfide (H2S) is a colorless, toxic gas with a pungent odor. It is produced in nature, industrial production, chemical reactions, and protein decomposition. In the human body, it plays a dual role: under physiological conditions, it acts as an important cardiovascular protectant and neuromodulator, regulating blood pressure and influencing nerve transmission by relaxing vascular smooth muscle; however, in specific pathological environments, such as bacterial infections, colon cancer, and diabetes, the concentration of H2S produced can be abnormally high, thus it can also serve as a signaling molecule for health detection. Therefore, developing a rapid-response, highly sensitive, and selective H2S detection method is of significant research importance and practical application value. Currently, common methods for detecting hydrogen sulfide include electrochemical methods, fluorescence sensing, and chromatography. Among these, fluorescence sensing is suitable for on-site H2S detection due to its advantages of high sensitivity, visualization, and rapid response.

[0003] Among numerous sensing methods, flexible fluorescent sensing films are widely used in environmental monitoring, biosensing, and smart protection due to their portability, flexibility, and ease of handling. Electrospinning technology can prepare micro / nanofiber membranes with high specific surface area. Its ease of modification and design provides an excellent platform for the preparation of multifunctional composite sensing materials and promotes the development of various high-performance flexible fluorescent sensors. However, existing flexible fluorescent sensing films suffer from low fluorescence efficiency and slow response, which greatly limits their application in H2S detection.

[0004] Based on this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing an electrospun thin film material composed of mesoporous silica nanoprobes. This invention utilizes an azide-based Schiff base derivative molecule (Az, such as...) that exhibits a fluorescent "open" response to hydrogen sulfide. Figure 1 (As shown) Silica was surface modified. A silica fluorescent probe with hydrogen sulfide sensing function was prepared, and a fluorescent sensing film for H2S detection was further prepared by electrospinning using this probe.

[0006] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is to provide a method for preparing an electrospun thin film material composed of mesoporous silica nanoprobes, comprising the following steps: S1, Aminoation: Mesoporous silica prepared by the sol-gel method, 3-aminopropyltriethoxysilane and toluene are mixed and reacted to obtain amino silica (NH2-SiO2). S2, Modification of p-carboxybenzaldehyde: The amino silica and p-carboxybenzaldehyde are mixed and reacted to obtain BH-SiO2; S3, Modification of 4-azidoaniline: The BH-SiO2, 4-azidoaniline hydrochloride and ethanol are mixed and reacted to obtain functionalized silica (Az-SiO2). S4. Electrospinning: The functionalized silica is dispersed in a solvent, and then polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) are added and mixed. Electrospinning is then performed to obtain the electrospinned thin film material of the mesoporous silica nanoprobe composite.

[0007] Furthermore, the specific steps for preparing mesoporous silica using the sol-gel method are as follows: dissolve hexadecyltrimethylammonium bromide in water, add ammonia, stir evenly at room temperature, add tetraethyl orthosilicate and n-hexane dropwise, heat and stir, then wash with ethanol, and vacuum dry to obtain mesoporous silica.

[0008] Furthermore, the volume ratio of tetraethyl orthosilicate to hexane is 1~2:2~3; the heating and stirring temperature is 35℃, and the time is 6~12h.

[0009] Preferably, the ratio of the mesoporous silica, 3-aminopropyltriethoxysilane and toluene is 1g:5~6mL:50~60mL.

[0010] Preferably, the reaction temperature in step S1 is 75~80℃ and the time is 12~24h.

[0011] Preferably, before being mixed with amino silica, the p-carboxybenzaldehyde is activated in a solvent with an activator; the activator includes N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride.

[0012] Further, the specific steps of step S2 are as follows: first, p-carboxybenzaldehyde, N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride are dissolved in ethanol and activated for 4~12h to obtain solution a, and then the amino silica is added to solution a and reacted for 4~12h to obtain BH-SiO2.

[0013] Furthermore, the mass ratio of p-carboxybenzaldehyde, N-hydroxysuccinimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and amino silica is 1~1.2:1~1.2:1~1.2:5~5.5.

[0014] Preferably, the mass ratio of BH-SiO2 to 4-azidoaniline hydrochloride is 5.5~6:1~1.3; the reaction temperature in step S3 is 75~80℃ and the reaction time is 12~24h.

[0015] Preferably, the mass ratio of the functionalized silica, polyacrylonitrile, and polyvinylpyrrolidone is 1~1.2:1.2~1.6:1~1.2; the solvent includes N,N-dimethylformamide (DMF); the electrospinning parameters are as follows: spinning speed is 0.2 mL / h, spinning humidity is 50%, spinning temperature is 27℃, and spinning distance is 20 cm.

[0016] The second technical solution of the present invention provides an electrospun thin film material composed of mesoporous silica nanoprobes prepared by the above preparation method.

[0017] The third technical solution of the present invention provides the application of the above-mentioned mesoporous silica nanoprobe composite electrospun film material in H2S detection.

[0018] This invention utilizes azide-based Schiff base compound (Az) to modify the surface of silica to obtain mesoporous silica nanoparticles (Az-SiO2), and then uses electrospinning to co-spin PAN, PVP and Az-SiO2 nanoparticles to obtain a mesoporous silica nanoprobe sensing film.

[0019] This invention prepares a mesoporous silica nanoprobe composite electrospun film material using PAN and PVP as matrices to encapsulate functionalized silica. This invention successfully achieves stable and uniform encapsulation of functionalized mesoporous silica nanoprobes within a polymer fiber matrix. The core of this invention lies in the following: First, uniformly sized spherical mesoporous silica is prepared using a sol-gel method combined with a surfactant template, followed by sequential modification with amination, p-carboxybenzaldehyde, and 4-azidoaniline. This series of surface modifications endows it with a fluorescent "switching" ability specifically for sensing H2S. Second, in the spinning solution preparation stage, the functionalized silica powder is first ground and ultrasonically dispersed separately in DMF solvent to effectively break down its soft agglomerates, forming a stable primary dispersion of nanoparticles. Then, polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) are added and mixed. PAN provides mechanical strength and the fiber skeleton, while PVP acts as a "binder," improving its affinity with functionalized particles. The two are blended in an optimized ratio (e.g., PAN:PVP:SiO2 mass ratio = 1.2~1.6:1~1.2:1~1.2) to ensure a balance between the formation of a continuous phase and the particle loading. The most crucial step is the electrospinning process: in a high-voltage electrostatic field, the polymer jet carrying the dispersed particles is violently stretched while the solvent rapidly evaporates. This causes a sharp increase in the viscosity of the polymer solution and rapid solidification, dynamically "capturing" and fixing the dispersed nanoparticles in situ, ultimately forming solid composite nanofibers. During this process, because the solidification rate is much faster than the migration or aggregation rate, the particles are perfectly embedded and encapsulated within the fiber, rather than adhering to the surface.

[0020] The present invention discloses the following technical effects: This invention utilizes electrospinning to encapsulate functionalized silica nanoparticles within a PAN / PVP matrix to form a fluorescent sensing film capable of sensing hydrogen sulfide. This material effectively combines optically functional units with ICT mechanisms, stable silica nanospheres, and a polymer spinning matrix, resulting in a novel mesoporous silica nanoprobe sensing film with excellent optical performance and high photostability. This flexible fluorescent sensing film shows significant application potential in fields such as flexible wearable hydrogen sulfide sensing. Attached Figure Description

[0021] Figure 1 The chemical formula structure of the azide-based Schiff base compound (Az) in the Az-SiO2 material in Example 2 is shown. Figure 2 The images show the SEM (left) and TEM (right) images of the Az-SiO2 material in Example 2. Figure 3 This is a particle size distribution diagram of the Az-SiO2 material in Example 2; Figure 4The Fourier transform infrared spectra of the NH2-SiO2, BH-SiO2, and Az-SiO2 materials in Example 2 are shown below. Figure 5 Small-angle X-ray scattering (SAXS) images of SiO2, NH2-SiO2, and Az-SiO2 materials in Example 2; Figure 6 The Fourier transform infrared spectra of Az-SiO2 before and after the reaction in Example 2 are shown below. Figure 7 The images show the XPS spectra of Az-SiO2 before and after the reaction in Example 2. The left image shows the reaction before hydrogen sulfide, and the right image shows the reaction after hydrogen sulfide. Figure 8 The images show the fluorescence emission spectra of Az-SiO2 in solutions with different hydrogen sulfide concentrations in Example 2. The inset shows the change in fluorescence intensity before and after the reaction under 2.2 mM hydrogen sulfide concentration. Figure 9 The fluorescence emission spectra of Az-SiO2 under different interfering molecules in Example 2 are shown. Figure 10 The images show the SEM (left) and TEM (right) images of the mesoporous silica nanoprobe sensing film in Example 3. Figure 11 The Fourier transform infrared spectra of the PAN+PVP and PAN+PVP+Az-SiO2 thin film materials in Example 3 are shown below. Figure 12 The fluorescence spectra of the mesoporous silica nanoprobe sensing film in solutions with different hydrogen sulfide concentrations are shown in Example 3. Figure 13 This is a photograph taken under a UV lamp after the mesoporous silica nanoprobe sensing film of Example 3 was reacted with hydrogen sulfide of different concentrations. Figure 14 The linear curves of the mesoporous silica nanoprobe sensing film in Example 3 under different concentrations of hydrogen sulfide (0~0.8mM); Figure 15 The fluorescence emission spectrum of the mesoporous silica nanoprobe sensing film in Example 3 under hydrogen sulfide and other interfering substances; Figure 16 This is a reaction flow diagram of the present invention. Detailed Implementation

[0022] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0023] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0024] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0025] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0026] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0027] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0028] Unless otherwise specified, "room temperature" in this invention refers to 25±2℃.

[0029] The raw materials used in the following embodiments and comparative examples of the present invention are all commercially available, and the source of commercially available products does not affect the technical effect of the present invention.

[0030] Unless otherwise specified, the concentration of ethanol in the following examples and comparative examples is anhydrous ethanol.

[0031] Example 1 Dissolve 1 g of hexadecyltrimethylammonium bromide in 160 mL of deionized water, add 7 mL of ammonia water, stir at room temperature for 0.5 h until homogeneous, then add 5 mL of tetraethyl orthosilicate and 10 mL of n-hexane dropwise, stir at 35 °C for 12 h, wash twice with ethanol, and vacuum dry for 12 h to obtain white powder SiO2.

[0032] Example 2 0.1 g SiO2 was added to 5 mL of toluene and 0.5 mL of 3-aminopropyltriethoxysilane, stirred until homogeneous, and stirred at 80 °C for 12 h. After centrifugation, washing, and vacuum drying, NH2-SiO2 was obtained. 150 mg of p-carboxybenzaldehyde, N-hydroxysuccinimide, and (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added to 20 mL of anhydrous ethanol and stirred for 4 h to obtain solution a. 751 mg of NH2-SiO2 was added to solution a and reacted at room temperature for 4 h. After centrifugation, the solution was washed several times with water and ethanol and dried to obtain BH-SiO2. 751 mg of the above BH-SiO2 and 136 mg of 4-azidoaniline hydrochloride were dispersed in 20 mL of anhydrous ethanol and reacted at 80 °C for 12 h. After rotary evaporation, the solution was washed with ethanol and vacuum dried to obtain Az-SiO2.

[0033] The microstructure of the obtained Az-SiO2 was observed and characterized, and its performance was tested. The results are as follows: Figures 2-9 As shown.

[0034] Figure 2 The images show the SEM (left) and TEM (right) images of the Az-SiO2 material in Example 2. Figure 3 This is a particle size distribution diagram of the Az-SiO2 material in Example 2. Figure 4 The Fourier transform infrared spectra of the NH2-SiO2, BH-SiO2, and Az-SiO2 materials in Example 2 are shown. Figure 5 Small-angle X-ray scattering (SAXS) images of SiO2, NH2-SiO2, and Az-SiO2 materials in Example 2 of this invention. Figure 6 The image shows the Fourier transform infrared spectra of Az-SiO2 before and after the reaction in Example 2. Figure 7 The images show the XPS spectra of Az-SiO2 before and after the reaction in Example 2. The left image shows the reaction before hydrogen sulfide, and the right image shows the reaction after hydrogen sulfide. Figure 8 The images show the fluorescence emission spectra of Az-SiO2 in solutions with different hydrogen sulfide concentrations in Example 2. The inset shows the change in fluorescence intensity before and after the reaction in hydrogen sulfide solutions with concentrations of 0–2.2 mM. Figure 9 The image shows the fluorescence emission spectra of Az-SiO2 under different interfering molecules in Example 2.

[0035] 1. Results of observation and characterization of microstructure: from Figure 2 As can be seen, the average particle size of Az-SiO2 is 475 nm, and the particle size of spherical nanoparticles varies from 225 to 675 nm, mainly concentrated in the range of 425 to 475 nm. Figure 2Az-SiO2 can be observed to be regularly spherical with a uniform two-dimensional hexagonal porous structure inside. Further analysis of Az-SiO2 using small-angle X-ray scattering (SAXS) reveals... Figure 5 As shown, a strong scattering peak is observed at 0.97, further demonstrating that the material has an ordered pore structure.

[0036] The synthesis of Az-SiO2 obtained in this embodiment was characterized as follows: Figure 4 As shown, the Fourier transform infrared spectrum at 1600 cm⁻¹ -1 The peak at 2100 cm⁻¹ exhibits the characteristic peaks of the benzene ring in carboxybenzaldehyde, which are clearly visible at this point. -1 The characteristic -N3 peak of 4-azidoaniline hydrochloride was observed at the position. These results demonstrate that Az is immobilized on NH2-SiO2 via a reaction.

[0037] 2. Results of hydrogen sulfide sensing test: Disperse 0.02 g of Az-SiO2 in 1 mL of ethanol to prepare the mother liquor. Prepare a solution with a concentration of 1 × 10⁻⁶. -3 A sodium sulfide solution of concentration M was prepared. 20 μL of the mother liquor was added to 2 mL of sodium sulfide solution. Before the reaction, the mesoporous silica molecules linked to Az-SiO2 possessed unique azide groups, and Az-SiO2 exhibited almost no fluorescence. Upon reaction with H2S, the azide groups were reduced to amino groups, exhibiting bright green fluorescence. The reaction mechanism was ICT (intramolecular charge transfer).

[0038] Figure 6 The Fourier transform infrared spectrum clearly shows that at 2100 cm⁻¹ -1 The disappearance of the characteristic -N3 peak of 4-azidoaniline hydrochloride at the position proves that the reduction of azide to amino group causes ICT, which in turn leads to the change in molecular fluorescence.

[0039] XPS was used to analyze the Az-SiO2 reaction before and after, such as Figure 7 As shown, XPS analysis of nitrogen valence state information revealed that the N1s spectrum before the reaction could be divided into three types: -CN-, -C=N-, and -N3 in Az-SiO2, with binding energies of 399.6 eV and 398.5 eV, respectively. Since azides consist of a central nitrogen atom and two peripheral nitrogen atoms, their binding energies were 399.6 eV and 401.3 eV, respectively. After the reaction, the N1s spectrum could be divided into three types: -CN-, -C=N-, and -NH2. Due to the excessively high binding energy of -NH2, the other two atoms were bundled together to form a single binding energy of 398.5 eV.

[0040] The reaction was characterized by fluorescence spectroscopy before and after the reaction, such as... Figure 8As shown, the fluorescence intensity was low before the reaction, but after the addition of hydrogen sulfide, the fluorescence exhibited an "open" type of bright green fluorescence, and the fluorescence intensity increased. Figure 8 As shown in the inset, under ultraviolet light, there is almost no fluorescence before the reaction, and the fluorescence after the reaction is a bright green.

[0041] Further investigation was conducted by testing the fluorescence properties of this molecule at different hydrogen sulfide concentrations (0, 0.6 × 10⁻⁶). -5 0.8×10 -5 0.9×10 -5 1×10 -5 1.1×10 -5 1.2×10 -5 1.4×10 -5 1.6×10 -5 1.8×10 -5 2.2×10 -5 Fluorescence changes of M) (e.g. Figure 8 As shown in the figure, it can be observed that the fluorescence intensity increases significantly with further increase in hydrogen sulfide concentration.

[0042] 3. Selective detection: In practical applications of hydrogen sulfide sensing, interference from other molecules is often present. Therefore, selectivity is also an important criterion for evaluating sensing performance, including Na2S, Na2S2O4, Na2S2O5, Na2SO3, Na2SO4, NaCl, and NaOH.

[0043] Disperse 0.02 g of Az-SiO2 in 1 mL of ethanol to prepare the mother liquor. All concentrations were 1 × 10⁻⁶. -4 M. Different interfering molecule solutions. Take 20 μL of the stock solution and add 2 mL of the different interfering molecule solution to each. Detect using a fluorescence spectrometer with an excitation wavelength of 365 nm.

[0044] The results are as follows Figure 9 As shown, when Az-SiO2 is placed in the above solution, the fluorescence intensity of Az-SiO2 for H2S increases significantly, while the fluorescence intensity for other interfering molecules does not change significantly. This indicates that Az-SiO2 has excellent selectivity for H2S sensing.

[0045] Example 3 0.3635 g of uniformly ground Az-SiO2 in a mortar was placed in 3 mL of N,N-dimethylformamide and ultrasonically dispersed for 10 min. Then, 0.4362 g of PAN and 0.3635 g of PVP were weighed and added to the above solution, and stirred at room temperature to obtain a spinning solution. Mesoporous silica nanoprobe sensing films were obtained by electrospinning using an electrospinning machine. The spinning speed was 0.2 mL / h, the spinning humidity was 50%, the spinning temperature was 27℃, and the spinning distance was 20 cm. The spinning needle was size 18.

[0046] 1. The microstructure of the obtained mesoporous silica nanoprobe sensing film was observed, and the results are as follows: Figure 10 As shown.

[0047] Figure 10 The images show the SEM (left) and TEM (right) images of the mesoporous silica nanoprobe sensing film in Example 3.

[0048] like Figure 10 The SEM images show that the Az-SiO2-doped fibers contain mesoporous silica nanoprobes, which are embedded within the fibers without obvious aggregation. Furthermore, the TEM images reveal that the Az-SiO2 is encapsulated within PAN and PVP matrices.

[0049] 2. Characterization of the fluorescent sensing thin film capable of sensing hydrogen sulfide: Figure 11 The Fourier transform infrared spectra of the PAN+PVP and PAN+PVP+Az-SiO2 thin film materials in Example 3 are shown. Figure 11 In this context, PAN+PVP+Az-SiO2 refers to the mesoporous silica nanoprobe sensing film prepared in Example 3; PAN+PVP refers to the film prepared by omitting Az-SiO2 based on the preparation method described in Example 3.

[0050] like Figure 11 As shown, the Fourier transform infrared spectrum at 1082 cm⁻¹ -1 The presence of characteristic peaks of silicon dioxide at the point of induction proves that Az-SiO2 has been successfully doped into PAN and PVP matrices.

[0051] 3. Study on the H2S sensing performance of fluorescent sensing films capable of sensing hydrogen sulfide: The response of mesoporous silica nanoprobe sensing films to H2S: The films were cut into 1cm × 2cm pieces and prepared with concentrations ranging from 0 to 2.0 × 10⁻⁶. -3 M was prepared by adding 2 mL of H2S solution of different concentrations to each solution. After reacting for 10-20 min, the reaction was detected by fluorescence spectroscopy with an excitation wavelength of 375 nm. Figure 12 The fluorescence spectra of the mesoporous silica nanoprobe sensing film in solutions with different hydrogen sulfide concentrations are shown in Example 3. Figure 13 These are photographs taken under a UV lamp after the mesoporous silica nanoprobe sensing film of Example 3 has been reacted with hydrogen sulfide of different concentrations. Figure 13 In the table, the concentrations in the first row from left to right are 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 mM; the concentrations in the second row from left to right are 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0 mM. Figure 12 As shown, in the presence of H2S, the fluorescence intensity at 473 nm of the mesoporous silica nanoprobe sensing film gradually increases with the increase of H2S concentration.

[0052] Figure 14 The linear curves of the mesoporous silica nanoprobe sensing film in Example 3 under different concentrations of hydrogen sulfide (0~0.8mM) are shown. Figure 14 As shown, the fluorescence intensity gradually increases with increasing hydrogen sulfide concentration, and within the range of 0–0.8 mM, there is a good linear relationship between H2S concentration and fluorescence intensity (R0). 2 =0.98), and the detection limit (LOD) was 13.5 μM obtained by using the 3S0 / k equation (k is the slope and S0 is the standard deviation), indicating that the mesoporous silica nanoprobe fluorescent sensing film has high sensitivity for H2S sensing.

[0053] 4. Selective detection: The fluorescence response of the mesoporous silica nanoprobe sensing film to various common volatile harmful substances was tested, including Na2S, Na2SO3, Na2SO4, Na2S2O4, Na2S2O5, as well as GSH, NaCl, NaOH, NaNO2, NaNO3, and NaHCO3.

[0054] The films were cut to 1cm × 2cm, and all were prepared with a concentration of 2.0 × 10⁻⁶. -3 Different interference molecule solutions of M were added in 2 mL each, and after reacting for 10-20 min, the samples were detected using a fluorescence spectrometer with an excitation wavelength of 375 nm.

[0055] The results are as follows Figure 15 As shown, when the mesoporous silica nanoprobe sensing film is placed in the above solution, the fluorescence intensity of the mesoporous silica nanoprobe sensing film for H2S increases significantly, while the fluorescence intensity for other interfering molecules does not change significantly. This indicates that the mesoporous silica nanoprobe sensing film has excellent selectivity for H2S sensing.

[0056] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0057] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an electrospun thin film material composed of mesoporous silica nanoprobes, characterized in that, Includes the following steps: Using mesoporous silica as raw material, functionalized silica is obtained by sequentially amination, modification with p-carboxybenzaldehyde, and modification with 4-azidoaniline. The functionalized silica is then mixed with polyacrylonitrile and polyvinylpyrrolidone to prepare an electrospinning solution, and electrospinning is performed to obtain an electrospinned thin film material composed of the mesoporous silica nanoprobe.

2. The preparation method according to claim 1, characterized in that, Includes the following steps: S1, Aminoation: Mesoporous silica, 3-aminopropyltriethoxysilane and toluene are mixed and reacted to obtain amino silica; S2, Modification of p-carboxybenzaldehyde: The amino silica and p-carboxybenzaldehyde are mixed and reacted to obtain BH-SiO2; S3, Modification of 4-azidoaniline: The BH-SiO2, 4-azidoaniline hydrochloride and ethanol are mixed and reacted to obtain functionalized silicon dioxide; S4. Electrospinning: The functionalized silica is dispersed in a solvent, and then polyacrylonitrile and polyvinylpyrrolidone are added and mixed. Electrospinning is then performed to obtain the electrospinned thin film material of the mesoporous silica nanoprobe composite.

3. The preparation method according to claim 2, characterized in that, The ratio of mesoporous silica, 3-aminopropyltriethoxysilane and toluene is 1g:5~6mL:50~60mL; the reaction temperature in step S1 is 75~80℃ and the time is 12~24h.

4. The preparation method according to claim 2, characterized in that, Before being mixed with amino silica, the p-carboxybenzaldehyde is first activated in a solvent with an activator; the activator includes N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride.

5. The preparation method according to claim 4, characterized in that, The specific steps of step S2 are as follows: First, p-carboxybenzaldehyde, N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride are dissolved in ethanol and activated for 4~12h to obtain solution a. Then, the amino silica is added to solution a and reacted for 4~12h to obtain BH-SiO2.

6. The preparation method according to claim 5, characterized in that, The mass ratio of p-carboxybenzaldehyde, N-hydroxysuccinimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and amino silica is 1~1.2:1~1.2:1~1.2:5~5.

5.

7. The preparation method according to claim 2, characterized in that, The mass ratio of BH-SiO2 to 4-azidoaniline hydrochloride is 5.5~6:1~1.3; the reaction temperature in step S3 is 75~80℃ and the reaction time is 12~24h.

8. The preparation method according to claim 2, characterized in that, The mass ratio of the functionalized silica, polyacrylonitrile, and polyvinylpyrrolidone is 1~1.2:1.2~1.6:1~1.2; the solvent includes N,N-dimethylformamide; the electrospinning parameters are as follows: spinning speed is 0.2 mL / h, spinning humidity is 50%, spinning temperature is 27℃, and spinning distance is 20 cm.

9. The electrospun thin film material of mesoporous silica nanoprobe composite prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the electrospun thin film material composed of mesoporous silica nanoprobes as described in claim 9 in H2S detection.

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