A method for preparing photoisomerization film by LB film technology

Abstract

The application relates to the technical field of nanomaterials, in particular to a method for preparing a photoisomerization film by using LB film technology. The method comprises the following steps: molecular selection, a preparation method, condition parameters and an experimental method, etc. The method uses the LB film technology, takes azobenzene glutamine amphiphilic molecules as a main body, dissolves the amphiphilic molecules L-GAZS in N,N-dimethylformamide to prepare an organic dispersion liquid with a concentration of 0.5-1.5 mmol / L, selects rhodamine B, saffron T and methylene blue as subphases, and prepares a thin film with photoisomerization through the LB technology. The method has the advantages of simple equipment and preparation method, easy operation, mild and easy-to-control reaction conditions, good stability of the composite film prepared by the LB technology, material saving and recyclability, and the like. The orientation degree of the LB film and the application thereof can be controlled by changing the types of the amphiphilic organic molecules, the number of the LB film layers and other conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nanomaterials, and more particularly to a method for preparing a photoisomerization film by using LB film technology. BACKGROUND

[0002] Langmuir-Blodgett (LB) self-assembly technology, as an effective means for preparing multilayer monolayer films, has been used to produce materials organized at the molecular level. LB technology is to transfer a monolayer film from an air / water interface to a solid substrate, so as to achieve controlled assembly of molecules and effectively manufacture highly ordered films with molecular precision. LB technology is widely applicable to various substances from organic molecules to nanomaterials. Supramolecular chirality refers to a stereoscopic structure constructed by non-covalent weak interaction forces, so that a molecule originally without chirality exhibits chirality signals (CD signals) under certain conditions, or the original chirality can be amplified through certain aggregation modes. Supramolecular structures are easy to be regulated by various means, and adjusting the molecular structure, packing mode or external stimuli (such as light, solvent, pH, temperature, ultrasound, oxidation and reduction, etc.) can change the supramolecular chirality.

[0003] In recent years, due to the advantages of non-contact, non-invasive, clean and wavelength controllable of light, the regulation of supramolecular chirality by light has attracted the interest of many researchers. The azobenzene glutamine amphiphilic molecule L-GAZS utilizes the characteristics of azobenzene photoisomerization, and designs and synthesizes glutamine amphiphilic molecules by connecting azobenzene to chiral glutamic acid. The reversible conversion of cis-trans isomers can be realized by light, and the special optical properties make it play an important role in the supramolecular of chiral optical switch. By combining LB film technology with azobenzene glutamine amphiphilic molecules, a composite film with photoisomerization characteristics is prepared, which provides a new idea for the preparation of functional self-assembled films and their applications as gas sensors, chiral switches, etc. SUMMARY

[0004] The present disclosure provides a method for preparing a photoisomerization film by using LB film technology, which uses azobenzene glutamine amphiphilic molecules as the main body and selects rhodamine B, safranin T and methylene blue as the sub-phase to prepare a composite film with photoisomerization characteristics.

[0005] In a first aspect, the present disclosure provides a method for preparing a photoisomerization film by using LB film technology, comprising the following steps:

[0006] (1) Preparation of LB film: Dissolve azobenzene glutamine amphiphilic molecule L-GAZS in N,N-dimethylformamide to prepare organic dispersion liquid. Pave the same volume of rhodamine B solution, safranine T solution and methylene blue solution on Langmuir-Blodgett trough respectively. Drop 50-100 μL of the L-GAZS organic dispersion liquid into the surface of different dye subphase respectively by using microsyringe. Form monolayer on the surface of subphase after treatment. Start the slide barrier in LB film to make the L-GAZS organic matter form compact and stable LB film with three different subphase surfaces respectively.

[0007] (2) Transfer of LB film: Make the surface pressure of the composite film of L-GAZS organic matter and three dyes reach 20-30 mN / m to prepare three kinds of L-GAZS / dye composite thin films. Transfer the three kinds of dye monolayer film to the corresponding substrate respectively by vertical lifting method or horizontal attachment method.

[0008] (3) Illumination of LB film: Place the L-GAZS / dye composite thin film transferred to the substrate under the ultraviolet lamp under specific conditions to obtain the photoisomerization thin film prepared by LB film technology.

[0009] Preferably, the step (1) specifically comprises the following steps: dissolve azobenzene glutamine amphiphilic molecule L-GAZS in N,N-dimethylformamide to prepare organic dispersion liquid and ultrasonic for 30 min. Wash Langmuir-Blodgett trough with ethanol and deionized water. Dissolve dyes rhodamine B, safranine T and methylene blue in deionized water respectively to prepare solutions with a concentration of 10 -3 M. Then, pave the same volume of rhodamine B solution, safranine T solution and methylene blue solution on Langmuir-Blodgett trough respectively. Drop 50-100 μL of the L-GAZS organic dispersion liquid into the surface of different dye subphase respectively by using microsyringe. Evaporate the solution for 15-30 min under the condition that the temperature of deionized water is 15-30℃ to form monolayer on the surface of subphase. Start the slide barrier in LB film to make the L-GAZS organic matter form compact and stable LB film with three different subphase surfaces respectively.

[0010] Preferably, the step (2) comprises the following steps: the surface pressure of the complex film formed by the L-GAZS organic matter and three dyes reaches 30 mN / m, and the monolayer films of L-GAZS / rhodamine B, L-GAZS / crocein T and L-GAZS / methylene blue are respectively transferred onto a quartz sheet, a glass sheet or a conductive glass substrate by a horizontal attachment method at a surface pressure of 20 mN / m, so as to prepare three kinds of L-GAZS / dye composite films, and the monolayer films of the three dyes are respectively transferred onto a mica sheet by a vertical lifting method at a surface pressure of 30 mN / m.

[0011] Preferably, the step (3) comprises the following steps: the L-GAZS / dye composite film transferred onto the substrate is irradiated under an ultraviolet lamp at room temperature and an ultraviolet light wavelength of 365 nm, so as to obtain the photoisomerization film prepared by the LB film technology.

[0012] Preferably, in the step (1), the azobenzene glutamine amphiphilic molecule is a glutamine amphiphilic molecule designed and synthesized by connecting azobenzene to chiral glutamic acid.

[0013] Preferably, in the step (1), the azobenzene glutamine amphiphilic molecule L-GAZS is dissolved in an organic matter dispersion liquid prepared by N,N-dimethylformamide to prepare a concentration of 0.5-1.5 mmol / L.

[0014] Preferably, in the step (1), the film pressure is detected by using a Whihelmy type surface tension tester to record the π-A curve of the relationship between the molecular area and the surface pressure at the different subphase interfaces.

[0015] Preferably, in the step (2), the monolayer films are respectively transferred onto the substrate by the horizontal attachment method for 40-80 times.

[0016] Preferably, in the step (3), the distance between the composite film and the ultraviolet light source is 10-15 cm, and the irradiation time is 30-60 min.

[0017] In summary, the present application has the following beneficial effects:

[0018] 1. In the present application, the LB film technology is used, the azobenzene glutamine amphiphilic molecule is used as the main body, and three dyes of rhodamine B, crocein T and methylene blue are selected as the subphase, so as to prepare a composite film with photoisomerization characteristics;

[0019] 2. The equipment and preparation method in the present application are simple and easy to operate, the reaction conditions are mild and easy to control, the composite film prepared by the LB technology has good stability, saves materials and can be recycled;

[0020] 3. This application provides a method for preparing a photo-isomerized composite film using LB film technology, which can control the orientation degree of the LB film and its application by changing conditions such as the type of amphiphilic organic molecules and the number of LB film layers.

[0021] It should be understood that the foregoing general description and the following detailed description are merely exemplary and explanatory and are not intended to limit the scope of protection of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 1. Figure 1 is a π-A curve diagram showing the relationship between the molecular area and the surface pressure at the interface between air and the subphase of the present application;

[0023] 2. Figure 2 is a transmission electron micrograph of the L-GAZS / ST composite film synthesized in this application;

[0024] 3. Figure 3 is the contact angle of the L-GAZS / ST composite film synthesized in this application;

[0025] 4. Figure 4 It is the ultraviolet spectrum of the L-GAZS / ST composite film synthesized in this application. DETAILED DESCRIPTION

[0026] The present application is further described in detail below with reference to the examples. It is particularly noted that if no specific conditions are specified in the following examples, the reactions are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0027] Example

[0028] Example 1

[0029] (1) Preparation of LB film:

[0030] The azobenzeneglutamine amphiphilic molecule L-GAZS was dissolved in N,N-dimethylformamide to prepare an organic dispersion with a concentration of 0.5 mmol / L and ultrasonicated for 30 minutes. The Langmuir-Blodgett trough was cleaned with ethanol and deionized water, and the dyes rhodamine B, safranin T, and methylene blue were dissolved in deionized water to prepare solutions with a concentration of 10-3 M. Then, equal volumes of rhodamine B solution, safranin T solution, and methylene blue solution were filled in the Langmuir-Blodgett trough. 50 μL of the L-GAZS organic dispersion was dropwise added to the surface of different dye subphases using a microsyringe. Under the condition of deionized water temperature of 25°C, the solution was evaporated for 15 minutes to form a monolayer on the subphase surface, which activated the sliding barrier in the LB film, allowing the L-GAZS organic compound to form dense and stable LB films on the surfaces of the three different subphases.

[0031] (2) Transfer of LB films:

[0032] The surface pressure of the complex film formed by L-GAZS organic matter and three dyes reached 30 mN / m. When the surface pressure was 20 mN / m, the monolayer films of L-GAZS / Rhodamine B, L-GAZS / Crocein T and L-GAZS / Methylene Blue were transferred onto quartz, glass or conductive glass substrates by horizontal attachment method, respectively, to prepare three kinds of L-GAZS / dye complex films. When the surface pressure was 30 mN / m, the monolayer films of the three dyes were transferred onto mica by vertical pulling method, respectively.

[0033] (3) Illumination of LB films:

[0034] The L-GAZS / dye complex films transferred onto the substrates were placed at a distance of 10 cm from the light source of the ultraviolet lamp at room temperature under the condition of ultraviolet light wavelength of 365 nm, and irradiated for 30 min, to obtain the photoisomerization films prepared by LB film technology.

[0035] As shown in Figure 1 , it is illustrated that the photoisomerization films prepared in the embodiment diffuse in different dye subphases, and the surface pressure increases significantly with the change of area, which illustrates that the self-assembly forms stable films.

[0036] As shown in Figure 2 , it is illustrated that the molecular size of the photoisomerization films prepared in the embodiment is about 2 μm.

[0037] As shown in Figure 3 , it is illustrated that the photoisomerization films prepared in the embodiment are hydrophobic films.

[0038] As shown in Figure 4 , it is illustrated that the photoisomerization films L-GAZS / ST prepared in the embodiment have red shift of absorption peak, and the dyes in the film exist in J aggregation form and self-assemble into ordered aggregates on the air-water interface.

[0039] Example 2

[0040] (1) Preparation of LB films:

[0041] The azobenzene glutamine amphiphilic molecule L-GAZS is dissolved in N,N-dimethylformamide to prepare an organic dispersion liquid with a concentration of 1.0 mmol / L and is ultrasonically treated for 30 min. The dye rhodamine B, safranine T and methylene blue are respectively dissolved in deionized water to prepare solutions with a concentration of 10-3 M. Then, the same volume of rhodamine B solution, safranine T solution and methylene blue solution are respectively spread on the Langmuir-Blodgett trough. 100 μL of the L-GAZS organic dispersion liquid is added dropwise to the surface of the different dye subphases by using a microsyringe. Under the condition that the temperature of deionized water is 25°C, the solution is evaporated for 15 min to form a monolayer on the surface of the subphase. The slide barrier in the LB film is started to make the L-GAZS organic matter form a compact and stable LB film with the three different subphase surfaces.

[0042] (2) Transfer of the LB film:

[0043] The surface pressure of the composite film formed by the L-GAZS organic matter and the three dyes reaches 30 mN / m. When the surface pressure is 20 mN / m, the monolayer films of L-GAZS / rhodamine B, L-GAZS / safranine T and L-GAZS / methylene blue are respectively transferred to a quartz sheet, a glass sheet or a conductive glass substrate by using the horizontal attachment method to prepare three kinds of L-GAZS / dye composite films. When the surface pressure is 30 mN / m, the monolayer films of the three dyes are respectively transferred to a mica sheet by using the vertical pulling method.

[0044] (3) Illumination of the LB film:

[0045] The L-GAZS / dye composite film transferred to the substrate is placed at a distance of 15 cm from the light source of the ultraviolet lamp under the condition that the room temperature and the wavelength of the ultraviolet light is 365 nm, and is irradiated for 45 min to obtain the photoisomerization film prepared by using the LB film technology.

[0046] Example 3

[0047] (1) Preparation of the LB film:

[0048] The azobenzene glutamine amphiphilic molecule L-GAZS is dissolved in N,N-dimethylformamide to prepare an organic dispersion liquid with a concentration of 1.5 mmol / L and is ultrasonically treated for 30 min. The dye rhodamine B, safranine T and methylene blue are respectively dissolved in deionized water to prepare solutions with a concentration of 10-3 M. Then the same volume of rhodamine B solution, safranine T solution and methylene blue solution are respectively spread on the Langmuir-Blodgett trough. 100 μL of the L-GAZS organic dispersion liquid is added dropwise to the surface of the different dye subphases by using a microsyringe. Under the condition that the temperature of deionized water is 25°C, the solution is evaporated for 30 min to form a monolayer on the surface of the subphase. The slide barrier in the LB film is started to make the L-GAZS organic matter form a compact and stable LB film with the three different subphase surfaces.

[0049] (2) Transfer of the LB film:

[0050] The surface pressure of the composite film formed by the L-GAZS organic matter and the three dyes reaches 30 mN / m. When the surface pressure is 20 mN / m, the monolayer films of L-GAZS / rhodamine B, L-GAZS / safranine T and L-GAZS / methylene blue are respectively transferred to a quartz sheet, a glass sheet or a conductive glass substrate by using the horizontal attachment method to prepare three kinds of L-GAZS / dye composite films. When the surface pressure is 30 mN / m, the monolayer films of the three dyes are respectively transferred to a mica sheet by using the vertical pulling method.

[0051] (3) Illumination of the LB film:

[0052] The L-GAZS / dye composite film transferred to the substrate is placed at a distance of 15 cm from the light source of the ultraviolet lamp under the condition that the room temperature and the wavelength of the ultraviolet light are 365 nm, and is irradiated for 60 min to obtain the photoisomerization film prepared by using the LB film technology.

[0053] Example 4

[0054] (1) Preparation of the LB film:

[0055] The azobenzene glutamine amphiphilic molecule L-GAZS was dissolved in N,N-dimethylformamide to prepare an organic dispersion liquid with a concentration of 1.5 mmol / L and was ultrasonicated for 30 min. The dye rhodamine B, safranine T and methylene blue were dissolved in deionized water to prepare solutions with a concentration of 10-3 M, respectively. Then, the same volume of the rhodamine B solution, the safranine T solution and the methylene blue solution were respectively spread on the Langmuir-Blodgett trough. 50 μL of the L-GAZS organic dispersion liquid was added dropwise to the surface of the different dye subphases by using a microsyringe. Under the condition that the temperature of the deionized water was 25°C, the solution was evaporated for 15 min to form a monolayer on the surface of the subphase. The slide barrier in the LB film was started to make the L-GAZS organic matter form a compact and stable LB film with the three different subphase surfaces, respectively.

[0056] (2) Transfer of the LB film:

[0057] The surface pressure of the composite film formed by the L-GAZS organic matter and the three dyes reached 30 mN / m. When the surface pressure was 20 mN / m, the monolayer films of L-GAZS / rhodamine B, L-GAZS / safranine T and L-GAZS / methylene blue were respectively transferred to a quartz sheet, a glass sheet or a conductive glass substrate by using the horizontal attachment method to prepare three kinds of L-GAZS / dye composite thin films. When the surface pressure was 30 mN / m, the monolayer films of the three dyes were respectively transferred to a mica sheet by using the vertical pulling method.

[0058] (3) Illumination of the LB film:

[0059] The L-GAZS / dye composite thin film transferred to the substrate was placed at a distance of 10 cm from the light source of the ultraviolet lamp under the condition that the room temperature and the wavelength of the ultraviolet light were 365 nm, and was irradiated for 45 min to obtain the photoisomerization thin film prepared by using the LB film technology.

[0060] Example 5

[0061] (1) Preparation of the LB film:

[0062] The azobenzeneglutamine amphiphilic molecule L-GAZS was dissolved in N,N-dimethylformamide to prepare an organic dispersion with a concentration of 1.0 mmol / L and ultrasonicated for 30 minutes. The Langmuir-Blodgett trough was cleaned with ethanol and deionized water, and the dyes rhodamine B, safranin T, and methylene blue were dissolved in deionized water to prepare solutions with a concentration of 10-3 M. Then, equal volumes of rhodamine B solution, safranin T solution, and methylene blue solution were filled in the Langmuir-Blodgett trough. 50 μL of the L-GAZS organic dispersion was dropwise added to the surface of different dye subphases using a microsyringe. Under the condition of deionized water temperature of 25°C, the solution was evaporated for 30 minutes to form a monolayer on the subphase surface, which activated the sliding barrier in the LB film, allowing the L-GAZS organic compound to form dense and stable LB films on the surfaces of the three different subphases.

[0063] (2) Transfer of LB film:

[0064] The surface pressure of the composite films formed by the L-GAZS organic compound and the three dyes reached 30 mN / m. At a surface pressure of 20 mN / m, single-layer films of L-GAZS / Rhodamine B, L-GAZS / Safranin T, and L-GAZS / methylene blue were transferred multiple times onto quartz, glass, or conductive glass substrates via a horizontal adhesion method to produce the three L-GAZS / dye composite films. At a surface pressure of 30 mN / m, the three dye monolayers were transferred onto mica sheets via a vertical Czochralski method.

[0065] (3) Illumination of LB film:

[0066] The L-GAZS / dye composite film transferred to the substrate was placed 15 cm away from the UV light source at room temperature and a UV wavelength of 365 nm and irradiated for 30 minutes to obtain a photo-isomerized film prepared using the LB film technology.

[0067] The above description is merely an exemplary embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A method for preparing a photoisomerization film using a LB film technique, characterized by, It comprises the following steps: (1) Preparation of LB film: Dissolve azobenzene glutamine amphiphilic molecule L-GAZS in N,N-dimethylformamide to prepare an organic dispersion solution, and then drop 50-100 μL of the L-GAZS organic dispersion solution into the subphase surface of rhodamine B solution, safranine T solution and methylene blue solution respectively, so as to form a monolayer on the subphase surface after treatment, and then start the slide barrier in the LB film to make the L-GAZS organic matter form a dense and stable LB film with the three different subphase surfaces respectively; (2) Transfer of LB film: The surface pressure of the composite film formed by the L-GAZS organic matter and the three dyes is 20-30 mN / m, and three kinds of L-GAZS / dye composite films are prepared, and then the three kinds of dye monolayer films are transferred to the corresponding substrates by vertical pulling method or horizontal attachment method; (3) Illumination of LB film: The L-GAZS / dye composite film transferred to the substrate is placed under the ultraviolet lamp at room temperature and under the condition of ultraviolet light wavelength of 365 nm, and the photoisomerization film prepared by LB film technology is obtained.

2. The method for preparing photoisomerization film using LB film technology according to claim 1, wherein, The step (1) comprises the following steps: dissolving azobenzene glutamine amphiphilic molecule L-GAZS in N,N-dimethylformamide, preparing an organic dispersion liquid and ultrasonicating for 30 min, washing the Langmuir-Blodgett tank with ethanol and deionized water, dissolving dyes rhodamine B, safranine T and methylene blue in deionized water respectively, and preparing the dyes into solutions with a concentration of 10 -3 M solution, and then spreading the same volume of rhodamine B solution, safranine T solution and methylene blue solution on the Langmuir-Blodgett tank respectively, and adding 50-100 μL of L-GAZS organic dispersion liquid drop by drop to the surface of different dye subphases by using a microsyringe, forming a monolayer on the surface of the subphase under the condition that the temperature of deionized water is 15-30 ℃, evaporating the solution for 15-30 min, and starting the slide barrier in the LB film to make the L-GAZS organic matter form a dense and stable LB film on the surface of the three different subphases respectively.

3. The method for preparing a photo-isomerized thin film using LB film technology according to claim 1, characterized in that: The step (2) specifically comprises the following steps: the surface pressure of the composite film formed by the L-GAZS organic matter and the three dyes is 20-30 mN / m, and the surface pressure of the L-GAZS / rodamine B, L-GAZS / safranine T and L-GAZS / methylene blue monolayer films is 20 mN / m, and the monolayer films are transferred to the quartz sheet, glass sheet or conductive glass substrate by horizontal attachment method, and three kinds of L-GAZS / dye composite films are prepared, and the surface pressure of the three dye monolayer films is 30 mN / m, and the three dye monolayer films are transferred to the mica sheet by vertical pulling method.

4. The method for preparing photoisomerization film using LB film technology according to claim 2, wherein, In the step (1), the azobenzene glutamine amphiphilic molecule is a glutamine amphiphilic molecule designed and synthesized by connecting azobenzene to chiral glutamic acid.

5. The method for preparing a photo-isomerized thin film using LB film technology according to claim 2, characterized in that: In the step (1), the azobenzene glutamine amphiphilic molecule L-GAZS is dissolved in N,N-dimethylformamide to prepare an organic dispersion solution with a concentration of 0.5-1.5 mmol / L.

6. The method for preparing photoisomerization film using LB film technology according to claim 2, wherein, In the step (2), the detection method of the surface pressure of the composite film is to use Whihelmy type surface tension tester to detect and record the π-A curve of the molecular area and surface pressure at the interface between air and different subphases.

7. The method for preparing a photo-isomerized thin film using LB film technology according to claim 3, characterized in that: In the step (2), the monolayer films are transferred to the substrate by horizontal attachment method for 40-80 times.

8. The method for preparing photoisomerization film using LB film technology according to claim 1, wherein, In the step (3), the distance between the composite film and the ultraviolet light source is 10-15 cm, and the irradiation time is 30-60 min.

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