Dithiophene ethylene-based transport films and methods of making the same

Abstract

The present application relates to the technical field of transmission film, and particularly relates to a transmission film based on dithiophene ethylene and a preparation method thereof.The transmission film comprises a base film and a light-controlled molecule, the light-controlled molecule is coated on the base film, and the light-controlled molecule has a light response group.The detection result shows that after ultraviolet light irradiation, the transmission film can quickly realize complete conversion from an open ring to a closed ring; after visible light irradiation is restored, the transmission film can be efficiently and reversibly restored to an open ring state.In addition, the transmission film has a high on-off ratio for five ions of sodium, potassium, lithium, magnesium and calcium.The dithiophene ethylene modified by a terminal amino group is used as a basic unit, the prepared transmission film based on dithiophene ethylene not only has rich nanochannels, but also has the characteristics of light response functional groups regulating nanometer pore switches, through the alternative irradiation of ultraviolet light and visible light, the closing and opening of the ion channel can be accurately regulated, and finally the controllability of the light-controlled ion transmission is realized.

Description

Technical Field

[0001] This invention relates to the field of transport membrane technology, and in particular to a transport membrane based on dithiophene ethylene and its preparation method. Background Technology

[0002] Photocontrolled ion channels are a class of proteins or synthetic structures that regulate transmembrane ion transport through light stimulation. They are broadly classified into natural and artificial photocontrolled ion channels. Natural photocontrolled ion channels are transmembrane proteins found in organisms, whose ion permeability is directly regulated by light of specific wavelengths. Artificial photocontrolled ion channels are synthetic structures that achieve precise regulation of transmembrane transport through photosensitive molecules. Their core mechanism involves using photoisomerization reactions to alter the channel conformation or surface charge, thereby mimicking the gating function of biological ion channels.

[0003] Precise regulation of the opening and closing of natural photogated ion channels is crucial for transmembrane ion transport and the regulation of cellular function. Taking rhodopsin 2 (ChR2), a photogated ion channel protein derived from *Chlamydomonas reinhardtii*, as an example, blue light stimulation induces a conformational change, opening the channel and allowing cations to transmembrane. Structural biology studies have shown that ChR2 is a seven-helix transmembrane protein with retinal as its chromophore. When ChR2 absorbs photons, the retinal Schiff base undergoes isomerization from all-trans to 13-cis. This process further triggers rearrangement of the protein's internal hydrogen bond network, increases the channel cavity volume, and simultaneously increases the number and mobility of water molecules, ultimately opening the channel. Therefore, subtle changes in the hydrogen bond network (especially alterations in the number and dynamics of water molecules) may be a key mechanism for the functional regulation of photogated ion channels.

[0004] In recent years, inspired by the ChR2 ion channel protein, research on light-gated ion channels has received widespread attention, especially in fields such as biological neuroscience, resource recycling, water purification, and sensors, where they have potential applications and have become a research focus. However, natural ion channel proteins exhibit poor physical and chemical stability in the in vitro environment, significantly limiting their direct application. Therefore, the development of artificial light-gated ion channels has become an inevitable requirement.

[0005] Currently, there are two main strategies for constructing artificial light-gated ion channels: one is to modify the surface of nanopores with photoresponsive functional groups. While this strategy can achieve the light-controlled function of ion channels, it is usually only applicable to the preparation of single ion channels, and the process is complex and difficult to scale up, severely limiting its practical application. The other strategy is to endow the microporous channels in the synthesized membrane with photoresponsive properties to achieve light-controlled ion transport. This method has higher practical value because it is easier to meet the needs of practical applications. However, the latter method still faces two technical challenges: first, the synthesized membrane material needs to have a large number of uniformly distributed nanochannels to ensure the high efficiency of ion transport and sieving performance; second, the photoresponsive molecules need to be precisely assembled into the interior of these nanochannels to achieve reliable light-switching and modulation functions.

[0006] Among the reported artificial light-gated ion channels, commonly used molecules (such as azobenzene derivatives) have slower photoresponse and smaller switching amplitudes compared to natural light-switched ion channel proteins, which limits their applications. Therefore, there is an urgent need to design novel light-controlled molecules and construct channels to improve light-control efficiency and stability. Summary of the Invention

[0007] The present invention aims to at least solve one of the technical problems existing in the related art. To this end, the first objective of the present invention is to provide a transport membrane based on dithiophene ethylene; the second objective of the present invention is to provide a method for preparing a transport membrane based on dithiophene ethylene.

[0008] To achieve the first objective, the technical solution adopted by this invention is as follows:

[0009] A transport membrane based on dithiophene ethylene includes a base membrane and photocontrol molecules, wherein the photocontrol molecules are coated on the base membrane;

[0010] The light-controlled molecule has a photoresponsive group. When irradiated with visible light, the photoresponsive group undergoes ring opening, and the light-controlled molecule forms the following structure:

[0011] ;

[0012] Under ultraviolet light irradiation, the photoresponsive group closes its ring, and the photocontrolled molecule forms the following structure:

[0013] ;

[0014] The reaction process of the photocontrolled molecules under visible light and ultraviolet light irradiation is as follows:

[0015]

[0016] Furthermore, the base film is selected from any one of polyacrylonitrile film, polyvinylidene fluoride film, polytetrafluoroethylene film, and polyethersulfone film.

[0017] Furthermore, the wavelength range of the visible light is 550nm to 750nm.

[0018] Furthermore, the wavelength range of the ultraviolet light is 310–360 nm.

[0019] Furthermore, it is used for the transport of photo-controlled ions.

[0020] Furthermore, the ions include Na + K + Li + Mg 2+ and Ca 2+ Any one or more of them.

[0021] To achieve the second objective, the technical solution adopted by this invention is as follows:

[0022] A method for preparing a dithiophene ethylene-based transport membrane, used to prepare any of the above-mentioned dithiophene ethylene-based transport membranes, includes the following steps:

[0023] S100, Compound IV Dissolved in a solvent, it yields a solution of compound IV;

[0024] S200. Apply the solution of compound IV onto the base film, let it stand for 5-15 minutes, and then apply compound V. The solution was coated onto the base film impregnated with the solution of compound IV. After interfacial polymerization for 10-20 min, the temperature was raised to 50-70 °C and the reaction was carried out for 5-15 min to obtain a transport membrane based on dithiophene ethylene.

[0025] Wherein, the structural formula of compound IV is It is an acid radical ion;

[0026] In the structural formula of compound V, R1 is selected from Cl. - or Br - .

[0027] Further, in step S100, the preparation of compound IV includes the following steps:

[0028] S110. Using compound I and compound II as raw materials, prepare compound III;

[0029] The structural formulas of compounds I, II, and III are shown below:

[0030] , , ;

[0031] S120, compound III, reacts with a salt-forming reagent to synthesize compound IV.

[0032] Further, in step S100, the solution concentration of compound IV is 0.1g / 100ml to 0.2g / 100ml.

[0033] Further, in step S100, the solvent is selected from an alcohol-water mixed solvent.

[0034] Furthermore, the volume ratio of alcohol to water in the mixed solvent is 1:1 to 2:1.

[0035] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0036] The present invention provides a dithiophene ethylene-based transport membrane, comprising a base membrane and photosensitive molecules coated on the base membrane. The photosensitive molecules possess photoresponsive groups that open under visible light irradiation and close under ultraviolet light irradiation. X-ray photoelectron spectroscopy (XPS) results of the dithiophene ethylene-based transport membrane and the PAN substrate demonstrate that the transport membrane successfully incorporates F and S elements, achieving modification of the PAN base membrane.

[0037] Experimental results for the detection of the dithiophene ethylene-based transport membrane show that:

[0038] After being irradiated with ultraviolet light, the transport membrane can quickly achieve a complete conversion from open-loop to closed-loop; after being irradiated with visible light again, the transport membrane can efficiently and reversibly return to the open-loop state.

[0039] Transport membrane to K + Na + and Li + The light on / off ratios of all three ions can be maintained at around 200, Mg 2+ Ca 2+ The on / off ratios for both types of ions can be maintained at around 300. This result indicates that the dithiophene ethylene-based transport membrane exhibits high on / off ratios for all five ions, implying high isomerization efficiency and a significant difference in ion transport capability before and after UV irradiation.

[0040] This invention uses dithiophene ethylene modified with terminal amino groups as the basic unit. The transport membrane based on dithiophene ethylene not only has abundant nanochannels, but also endows it with the characteristic of controlling the opening and closing of nanopores by photoresponsive functional groups. By alternating irradiation with ultraviolet light and visible light, the closing and opening of ion channels can be precisely controlled, and the controllability of photocontrolled ion transport can be achieved.

[0041] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0042] Figure 1 This is a scanning electron microscope (SEM) image of the dithiophene ethylene-based transport membrane (DTE membrane) provided in Embodiment 2 of the present invention.

[0043] Figure 2 This is a SEM image of the polyacrylonitrile (PAN) base film provided in Example 2 of the present invention.

[0044] Figure 3 These are XPS spectra of the DTE-O membrane, DTE-C membrane, and PAN-based membrane provided in Embodiment 2 of the present invention.

[0045] Figure 4 This is a schematic diagram of the testing equipment provided in the test example of the present invention.

[0046] Figure 5 This is an example of the present invention, showing the IV curves of the DTE membrane and the PAN base membrane before and after ultraviolet irradiation in a 0.1M KCl solution.

[0047] Figure 6 This is a diagram illustrating the changes in the It curve of the DTE membrane before and after irradiation with ultraviolet and visible light in a 0.1M KCl solution, as provided in the test example of this invention.

[0048] Figure 7 This is a diagram illustrating the changes in current at 1V corresponding to 10 cycles of irradiation with ultraviolet light and visible light on a DTE membrane in a 0.1M KCl solution, as provided in the test example of this invention.

[0049] Figure 8 The above is an example of the present invention, showing the IV curves of the DTE membrane and the PAN base membrane before ultraviolet light irradiation in solutions of KCl, NaCl, LiCl, MgCl2 and CaCl2 with concentrations of 0.1M.

[0050] Figure 9 The above is an example of the present invention, showing the IV curves of the DTE membrane and the PAN base membrane after ultraviolet light irradiation in solutions of KCl, NaCl, LiCl, MgCl2 and CaCl2 with concentrations of 0.1M.

[0051] Figure 10 The DTE membrane provided in the test example of this invention is for K + Na+ Li + Mg 2+ Ca 2+ The bar chart shows the ratio of light switches to light switches. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention, but cannot be used to limit the scope of this invention.

[0053] In the following embodiments, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used are commercially available, unless otherwise specified, and are carried out in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions.

[0054] Example 1

[0055] Preparation of compound IV The synthetic route is shown below:

[0056] ;

[0057] Its preparation process is as follows:

[0058] Compound I (1 mmol, 530 mg), compound II (2.2 mmol, 650 mg), Na₂CO₃ (0.42 g, 4 mmol), and Pd(PPh₃)₄ (0.25 mmol, 289 mg) were added to a 500 mL double-necked round-bottom flask, followed by the addition of 1,4-dioxane (180 mL) and water (40 mL), and mixed thoroughly. The mixture was refluxed at 90 °C for 48 h under a dry nitrogen atmosphere, cooled to room temperature, and extracted with CH₂Cl₂ (3 × 50 mL). The organic phases were combined, washed with saturated brine (3 × 30 mL), dried over anhydrous Na₂SO₄, filtered, and the solvent was removed by vacuum distillation to obtain a crude product. This crude product was purified by silica gel column chromatography (using a mixture of petroleum ether and ethyl acetate as eluent, volume ratio 2:1) to obtain compound III.

[0059] Compound III was dissolved in dichloromethane (100 ml) and acidified with 1 M HCl ethanol solution (5 ml) to obtain compound IV.

[0060] Example 2

[0061] The preparation process of the transport membrane based on dithiophene ethylene is as follows:

[0062] Compound IV (0.1 g) was dissolved in a mixed solvent of EtOH / H2O (volume ratio 1:1) (100 ml) to obtain a compound IV solution with a concentration of 0.1 g / 100 ml. This solution was coated onto a PAN substrate film and held for 10 min. After removing excess aqueous solution, a 1,3,5-benzenetricarboxyl chloride dichloromethane solution (0.1 g / 100 ml, 100 ml) was coated onto the PAN substrate film impregnated with the compound IV solution and poured in. Interfacial polymerization was carried out for 10–20 min to form a polyamide network. After removing excess organic solvent, the temperature was raised to 60°C and held for 10 min to carry out further crosslinking, resulting in a dithiophene ethylene-based transport membrane, denoted as the DTE membrane. Its SEM image is shown below. Figure 1 As shown:

[0063] As can be seen from the surface image, the surface is composed of uniform nanoparticles with clear particle boundaries, forming a dense "particle film" structure with no obvious pores.

[0064] Figure I shows the macroscopic structure of the DTE membrane cross-section. As can be seen from the figure, the cross-section exhibits the characteristics of "porous support + surface coating".

[0065] Section II focuses on the internal structure of the surface coating. As can be seen from this figure, the nanoparticles are tightly packed together, with tiny gaps between the particles, forming a "loose but continuous" skeleton. The surface particles are more dense.

[0066] SEM image of the surface of the PAN-based film without photosensitive molecules, as shown. Figure 2 As shown in the figure, obvious pores are distributed on the surface;

[0067] The DTE membrane prepared above was washed with n-hexane and then stored in deionized water for later use.

[0068] The above preparation process was completed at room temperature and relative humidity of 45-60%.

[0069] In this embodiment, a PAN base film is used as an example, but it is not limited to this. Other films with nanochannels can also be selected as base films, such as polyvinylidene fluoride film, polytetrafluoroethylene film, and polyethersulfone film.

[0070] The DTE film transforms into a closed-ring structure under ultraviolet light (310–360 nm) irradiation, denoted as DTE-C; and reverts to an open-ring structure under visible light (≥550 nm) irradiation, denoted as DTE-O. The reaction process is shown below:

[0071]

[0072] XPS spectra of DTE membrane and PAN substrate, as follows Figure 3 As shown in the figure, the PAN-based membrane spectrum does not contain characteristic peaks of F and S elements, while the DTE-O membrane and DTE-C membrane spectra both contain characteristic peaks of F and S elements. This result indicates that F and S elements were successfully introduced into the DTE membrane.

[0073] Detection Example 1

[0074] The DTE membrane prepared in Example 1 was used as the test sample, and the PAN base membrane without photocontrol molecules was used as the blank control.

[0075] Testing equipment such as Figure 4 As shown, the membrane to be tested (DTE membrane or PAN-based membrane) is clamped in the middle of the "H"-shaped device. Equal volumes of 0.1M salt solution (15-20 ml) are added to both sides of the membrane to be tested. Silver / silver chloride (Ag / AgCl) electrodes are used as electrodes and clamped in the solution at both ends. Then, a picoammeter is used to apply voltage and record the changes before and after light exposure.

[0076] The IV curves of the DTE membrane and the PAN-based membrane before and after irradiation with ultraviolet light (wavelength 310 nm) in a 0.1 M KCl solution are shown below. Figure 5 As shown in the figure, the conductivity of the DTE film drops abruptly after UV irradiation, indicating that the DTE film is sensitive to UV light (photosensitive conductivity switching characteristic); the conductivity of the PAN base film does not change significantly after UV irradiation, indicating that the PAN base film is not responsive to UV light.

[0077] The It curves of the DTE membrane before and after irradiation with ultraviolet light (wavelength 310 nm) and visible light (wavelength 550 nm) in a 0.1 M KCl solution are shown below. Figure 6 As shown in the figure, the current remains at a high value (around 220 μA) when there is no ultraviolet light irradiation, indicating that the DTE film has good conductivity under visible light. After ultraviolet light irradiation, the current drops sharply to the off state, which shows that the DTE film is rapidly affected by ultraviolet light. After the ultraviolet light stops and visible light irradiation is completed, the current quickly rises back to the initial high value, indicating that visible light can restore the conductivity of the DTE film and achieve a reversible switch from "off" to "on". This result shows that the response of the DTE film to ultraviolet light is a non-destructive and reversible response.

[0078] In a 0.1 M KCl solution, the changes in current at 1 V were observed after 10 cycles of irradiation with ultraviolet light (310 nm) and visible light (550 nm). Figure 7As shown in the figure, it can be seen that from 0 to 10 cycles, the pattern of "visible light on, ultraviolet light off" repeats, and the "on / off" amplitude of the current is stable without significant attenuation. This result indicates that the DTE film has good reversibility and cycle stability in response to visible and ultraviolet light.

[0079] The IV curves of the DTE membrane and the PAN-based membrane before UV irradiation are shown in solutions of KCl, NaCl, LiCl, MgCl2, and CaCl2 at concentrations of 0.1 M, respectively. Figure 8 As shown;

[0080] The IV curves of the DTE membrane and the PAN-based membrane after irradiation with ultraviolet light (wavelength 310 nm) in solutions of KCl, NaCl, LiCl, MgCl2, and CaCl2 with concentrations of 0.1 M, respectively, are shown below. Figure 9 As shown;

[0081] right Figure 8 and Figure 9 Comparative analysis reveals that the DTE film exhibits a sensitive and reversible response to ultraviolet light irradiation (current is "off" under ultraviolet light irradiation and "on" under visible light irradiation, demonstrating strong cycle stability); the PAN base film shows no obvious correlation characteristics of "light-controlled current switching," indicating that the PAN base film has no photoresponse performance.

[0082] DTE membrane for K + Na + Li + Mg 2+ Ca 2+ The optical switch ratio, such as Figure 10 As shown in the figure, the on / off ratios of the DTE membrane for the five ions are different; among them, K + Na + and Li + The light on / off ratio of the three ions is around 200, Mg 2+ Ca 2+ The on / off ratio for the two ions was around 300. This result indicates that the dithiophene ethylene-based transport membrane has a high on / off ratio for the five ions mentioned above, implying that the transport membrane has high isomerization efficiency and that the ion transport capacity before and after UV irradiation differs significantly.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a transport membrane based on dithiophene ethylene, characterized in that, Includes the following steps: S100, Compound IV Dissolved in a solvent, it yields a solution of compound IV; S200. Apply the solution of compound IV onto the base film, let it stand for 5-15 minutes, and then apply compound V. The solution was coated onto the base film impregnated with the solution of compound IV. After interfacial polymerization for 10-20 min, the temperature was raised to 50-70 °C and the reaction was carried out for 5-15 min to obtain a transport membrane based on dithiophene ethylene. Wherein, the structural formula of compound IV is It is an acid radical ion, and R1 in the structural formula of compound V is selected from Cl. - or Br - ; The base membrane is selected from any one of polyacrylonitrile membrane, polyvinylidene fluoride membrane, polytetrafluoroethylene membrane, and polyethersulfone membrane.

2. The method for preparing the transport membrane based on dithiophene ethylene as described in claim 1, characterized in that, In step S100, the preparation of compound IV includes the following steps: S110. Using compound I and compound II as raw materials, prepare compound III; The structural formulas of compounds I, II, and III are shown below: 、 、 ； S120, compound III, reacts with a salt-forming reagent to synthesize compound IV.

3. The method for preparing the transport membrane based on dithiophene ethylene as described in claim 1, characterized in that, In step S100, the concentration of the compound IV solution is 0.1 g / 100 ml to 0.2 g / 100 ml.

4. The method for preparing the transport membrane based on dithiophene ethylene as described in claim 1, characterized in that, In step S100, the solvent is selected from an alcohol-water mixed solvent, wherein the volume ratio of alcohol to water in the mixed solvent is 1:1 to 2:

1.

5. A transport membrane based on dithiophene ethylene, characterized in that, The membrane is prepared using the method for preparing a dithiophene ethylene-based transport membrane as described in any one of claims 1 to 4, comprising a base membrane and photocontrol molecules, wherein the photocontrol molecules are coated on the base membrane; The base film is selected from any one of polyacrylonitrile film, polyvinylidene fluoride film, polytetrafluoroethylene film, and polyethersulfone film. The light-controlled molecule has a photoresponsive group. When irradiated with visible light, the photoresponsive group undergoes ring opening, and the light-controlled molecule forms the following structure: ； Under ultraviolet light irradiation, the photoresponsive group closes its ring, and the photocontrolled molecule forms the following structure: 。 6. The transport membrane based on dithiophene ethylene as described in claim 5, characterized in that, The wavelength range of the visible light is 550nm to 750nm.

7. The transport membrane based on dithiophene ethylene as described in claim 5, characterized in that, The wavelength range of the ultraviolet light is 310–360 nm.

8. The transport membrane based on dithiophene ethylene as described in claim 5, characterized in that, Used for photo-controlled ion transport.

9. The transport membrane based on dithiophene ethylene as described in claim 8, characterized in that, The ions include Na. + K + Li + Mg 2+ and Ca 2+ Any one or more of them.

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