Photopolymer for improving polarization holographic performance and preparation method and application thereof

Abstract

The invention relates to the technical field of Irgacure 784 / PMMA (TI / PMMA) photopolymers, and discloses a photopolymer for improving polarization holographic performance and a preparation method and application thereof. According to the method, a three-dimensional carbon nanotube array (SWNTs and ZSM-5) is introduced into the photopolymer, the polarization holographic performance of the TI / PMMA photopolymer can be remarkably enhanced, the highest polarization diffraction efficiency in the photopolymer reported so far is achieved, and when the doping concentration is 0.002 wt%, the polarization diffraction efficiency of the photopolymer reaches 22.74%. Subsequently, through recording and reconstruction of a real object, the polarization holographic recording capability of the photopolymer is verified. In addition, the mechanism of improving the polarization diffraction efficiency of the SWNTs (at) ZSM-5 doped photopolymer is studied through molecular dynamics simulation, and the technology has important significance in application of the photopolymer in polarization holography.

Description

Technical Field

[0001] The present application relates to the technical field of TI / PMMA photopolymers, and in particular, to a photopolymer for improving polarization holographic performance, its preparation method and application. Background Art

[0002] Photopolymers have established a crucial position in polymer materials and have been widely used in photolithography, holographic display, and holographic storage. Compared with traditional holographic storage materials (such as silver halide plates, dichromated gelatin, photorefractive materials, azo polymers), photopolymers have the advantages of eliminating wet chemical processing, lower cost, stable performance, high diffraction efficiency, and wide dynamic range. These advantages make photopolymers one of the most promising media for holographic storage. In the current era of exponential data growth, volume holographic optical storage technology provides an energy-saving, low-cost, and high-density solution.

[0003] TI / PMMA is a typical photopolymer material and has been widely studied in traditional holography due to its low shrinkage rate, high photosensitivity, and high storage density. However, the low polarization diffraction efficiency of TI / PMMA is a significant drawback, which limits its wide application in polarization holography. Polarization holography records additional information about the polarization of light on the basis of traditional holography, providing new degrees of freedom for photopolymers in holographic storage and optical field control. To improve the polarization diffraction efficiency of the material, common solutions include doping nanomaterials (such as carbon nanotubes) into the photopolymer. However, the spatial structure of carbon materials will affect the photoinduced anisotropy of the photopolymer. Although the diffraction efficiency of traditional holography is improved, the polarization holographic diffraction efficiency is significantly reduced.

[0004] In view of this, a photopolymer that can improve polarization holographic performance is urgently needed in the current industry. Summary of the Invention

[0005] Based on the above analysis, the object of the present invention is to solve the problem of low polarization diffraction efficiency performance of photopolymers in the prior art, and to provide a photopolymer for improving polarization holographic performance, its preparation method and application.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] The present invention first discloses a photopolymer for improving polarization holographic performance, comprising the following raw materials:

[0008] Methyl methacrylate (MMA), photosensitizer Irgacure 784 (TI), azobisisobutyronitrile (AIBN), three-dimensional carbon nanotube array (SWNTs@ZSM-5); wherein:

[0009] The mass ratio of MMA, TI, AIBN, and SWNTs@ZSM-5 is 100:4:1.2:0.0005 to 0.0035.

[0010] The present invention also discloses a preparation method of a photopolymer for improving polarization holographic performance, comprising the following steps:

[0011] S1. Use a silica gel gasket to make a mold with a thickness of 1.5 mm, and place the mold and syringe in an incubator at 60°C.

[0012] S2. Weigh 1 g of three-dimensional carbon nanotube arrays and add them to 10 g of methyl methacrylate solution, and perform constant-temperature oscillation treatment to uniformly disperse the three-dimensional carbon nanotube arrays in methyl methacrylate to obtain a three-dimensional carbon nanotube array dispersion.

[0013] S3. Weigh the methyl methacrylate solution according to the weight ratio of claim 1 and place it in a dried brown bottle, and add the three-dimensional carbon nanotube array dispersion obtained in S2 thereto. The mixed solution is subjected to constant-temperature oscillation treatment to obtain a first mixed solution.

[0014] S4. Add the photosensitizer Irgacure 78 and azobisisobutyronitrile to the brown bottle in S3, and then subject the mixed solution to constant-temperature oscillation treatment to obtain a second mixed solution.

[0015] S5. Place a magnetic rotor in the brown bottle of the second mixed solution, then put it into a water bath magnetic stirrer and stir at a constant temperature until the solution in the brown bottle becomes viscous, then stop stirring to obtain a third mixed solution.

[0016] S6. Take out the brown bottle of the third mixed solution, place it in a 60°C water bath and ultrasonically vibrate for 2 min to obtain a fourth mixed solution.

[0017] S7. Take out the syringe and mold in S1, draw the fourth mixed solution in S6 with the syringe, inject it into the mold, and then perform constant-temperature heat preservation treatment. After the heat preservation ends, a solid photopolymer is obtained.

[0018] S8. Place the solid photopolymer in a refrigerator at 2°C, take it out after 2 h, and demold to obtain a photopolymer for improving polarization holographic performance.

[0019] Further, the temperature of the constant-temperature oscillation treatment in step S2 is 60°C, and the treatment time is 2 h.

[0020] Further, the temperature of the constant-temperature oscillation treatment in step S3 is 60°C, and the treatment time is 20 min.

[0021] Further, the temperature of the constant-temperature oscillation treatment in step S4 is 60°C, and the treatment time is 20 min.

[0022] Further, the constant temperature stirring conditions in step S5 are: the stirring temperature is 60°C, the stirring speed is 3000 rpm, and the stirring time is 60 min.

[0023] Further, the constant temperature heat preservation treatment conditions in step S7 are: constant temperature heat preservation at 60°C for 24 h.

[0024] The present invention also discloses a photopolymer for improving polarization holographic performance prepared by any of the above preparation methods.

[0025] The present invention also discloses an application of the above photopolymer for improving polarization holographic performance in the preparation of holographic optical elements.

[0026] Further, the holographic optical element is a holographic storage material.

[0027] The beneficial effects of the present invention:

[0028] 1. The present invention provides a method for obtaining a three-dimensional carbon nanotube array-doped TI / PMMA photopolymer holographic storage material and its preparation method. SWNTs@ZSM-5 is doped in TI / PMMA to realize the excellent medium of the photopolymer material for holographic storage; and it has a high polarization diffraction efficiency and can be better used for the production of holographic optical elements compared with TI / PMMA.

[0029] 2. The preparation process of the photopolymer material doped with a three-dimensional carbon nanotube array in the present invention is simple and the price is low, which is suitable for industrial production applications. Description of the drawings

[0030] Figure 1 It is a schematic diagram of the optical path for measuring the polarization holographic diffraction efficiency;

[0031] Figure 2 It is a schematic diagram of the evolution curve of the polarization holographic diffraction efficiency of TI / PMMA photopolymers with different doping concentrations over time;

[0032] Figure 3 It is a schematic diagram of the maximum polarization holographic diffraction efficiency of TI / PMMA photopolymers at different doping concentrations;

[0033] Figure 4 It is a schematic diagram of the optical path for polarization holographic recording of an actual object;

[0034] Figure 5 It is a schematic diagram of the polarization holographic recording of an actual object and a reconstructed image;

[0035] Figure 6 It is a sample of the photopolymer material. Detailed implementation manners

[0036] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0037] Example 1

[0038] In this example, the doped SWNTs@ZSM-5 nanoparticle photopolymer holographic recording material is prepared through the following steps:

[0039] S1: Clean the brown bottles, spatulas, magnetic rotors, silica gel gaskets, etc. required for the experiment with absolute ethanol. Set the constant temperature oven to 60 °C, and put the cleaned experimental utensils into the constant temperature oven until they are dried.

[0040] S2: Take out the silica gel gasket and make a mold with a thickness of 1.5 mm. After making, place the mold in the constant temperature oven, and also put the syringe into the constant temperature oven.

[0041] S3: Weigh 0.5 g of SWNTs@ZSM-5 and add it to 10 g of MMA solution. Place the mixed solution in a 60 °C constant temperature water bath and ultrasonically vibrate for 2 h. Then, SWNTs@ZSM-5 is evenly dispersed in MMA to obtain a three-dimensional carbon nanotube array dispersion.

[0042] S4: Weigh the corresponding weight (100 g) of MMA solution and place it in a dried brown bottle. Weigh 1 g of the three-dimensional carbon nanotube array dispersion in S3 and add it to the MMA solution in the brown bottle, and oscillate for 20 min.

[0043] S5: Subsequently, weigh the photoinitiator Irgacure 784 (4 g) and the thermal initiator AIBN (1.2 g) and add them to the brown bottle as well.

[0044] S6: Place the reagent bottle in a 60 °C water bath and ultrasonically vibrate the mixed solution for 20 min. This step can dissolve the powdery photoinitiator and thermal initiator in the MMA solution and start the thermal polymerization stage.

[0045] S7: Place a magnetic rotor in the brown bottle containing the mixed solution and put it into a water bath magnetic stirrer. Keep the temperature of the stirrer constant at 60 °C.

[0046] S8: Set the rotation speed of the magnetic stirrer to 3000 rpm and start stirring. During the stirring process, the thermal initiator decomposes and MMA starts to polymerize until the solution becomes viscous, then stop stirring.

[0047] S9: Put the viscous solution into a 60 °C water bath and ultrasonically vibrate for 2 min to remove the small bubbles in the viscous solution.

[0048] S10: Take out the syringe and the mold. Draw the solution with the syringe and inject it into the mold with a thickness of 1.5 mm. Then place it in an incubator at 60 °C and take it out after 24 h. At this time, the photopolymer has formed a solid state.

[0049] S11: Put the taken-out photopolymer into a refrigerator at 2 °C to stop the thermal polymerization. Take it out after 2 h and demold it.

[0050] Example 2

[0051] The preparation method of the photopolymer material in this example is the same as that in Example 1, except that: the addition amount of SWNTs@ZSM-5 in step S3 is 1 g.

[0052] Example 3

[0053] The preparation method of the photopolymer material in this example is the same as that in Example 1, except that: the addition amount of SWNTs@ZSM-5 in step S3 is 1.5 g.

[0054] Example 4

[0055] The preparation method of the photopolymer material in this example is the same as that in Example 1, except that: the addition amount of SWNTs@ZSM-5 in step S3 is 2.0 g.

[0056] Example 5

[0057] The preparation method of the photopolymer material in this example is the same as that in Example 1, except that: the addition amount of SWNTs@ZSM-5 in step S3 is 2.5 g.

[0058] Example 6

[0059] The preparation method of the photopolymer material in this example is the same as that in Example 1, except that: the addition amount of SWNTs@ZSM-5 in step S3 is 3.0 g.

[0060] Example 7

[0061] The preparation method of the photopolymer material in this example is the same as that in Example 1, except that: the addition amount of SWNTs@ZSM-5 in step S3 is 3.5 g.

[0062] Comparative Example 1

[0063] The preparation method of the photopolymer material in this example is the same as that in Example 1, except that: the addition amount of SWNTs@ZSM-5 in step S3 is 0 g, that is, SWNTs@ZSM-5 is not doped.

[0064] Test Example 1

[0065] Diffraction efficiency comparison experiment:

[0066] For the products of Examples 1-7 and Comparative Example 1, diffraction efficiency detection and calculation were carried out through the detection optical path as shown in the appendix Figure 1 A single longitudinal mode semiconductor laser with a wavelength of 532 nm was used to generate a laser light source, which reached the plane mirror M1 through an attenuator. The laser was expanded and collimated by an expanding and filtering system through the plane mirror, passed through an aperture stop, and the signal light power was modulated by a half-wave plate 1 (HWP1) to be consistent with the reference light power, and then reached a polarization beam splitter (PBS) through an electronic shutter 1. At this time, the light source was divided into a signal light and a reference light with two mutually perpendicular polarization states. The reference light was reflected onto the flat mirror M3 and transmitted onto the plane mirror M2. The laser beam diameter was set to 5 mm, and the power of each laser beam was 5 mW. During the measurement process, the polarization state of the signal light was maintained in the horizontal polarization state (p-pol), and the polarization state of the reference light was maintained in the vertical polarization state (s-pol). After passing through the plane mirror M2, the signal light passed through a half-wave plate to modulate the signal light power to be consistent with the reference light power, and then irradiated the obtained photopolymer product. The reference light reached the photopolymer through the plane mirror M3. The two beams of light met on the surface of the photopolymer and interfered, forming a phase-type volume holographic grating inside. Two photodetectors (photodetector 1) and a photodetector (photodetector 2) with an included angle of 26° were placed behind the photopolymer. The first photodetector obtained the average power of the transmitted light I0, and the second photodetector obtained the average power of the diffracted light I1. The diffraction efficiency was obtained by the following formula:

[0067]

[0068] where I0 is the intensity of the transmitted light and I1 is the intensity of the diffracted light.

[0069] The evolution of the polarization holographic diffraction efficiency of Examples 1-7 and Comparative Example 1 with time was tested. The test results are shown in Figure 2 ; It can be seen from Figure 2 that the SWNTs@ZSM-5 doped TI / PMMA photopolymer of Example 4 showed the best polarization holographic diffraction efficiency and reached the saturated diffraction efficiency earlier.

[0070] The maximum polarization diffraction efficiency of Examples 1-7 and Comparative Example 1 was tested. The test results are shown in Figure 3 ; It can be seen from Figure 3 that the maximum polarization diffraction efficiency of the SWNTs@ZSM-5 doped TI / PMMA photopolymer of Example 4 reached the best effect of 22.74%, which was nearly 2.6 times that of the TI / PMMA photopolymer of Comparative Example 1, significantly enhancing the polarization holographic performance of the material.

[0071] Application Example 1

[0072] Holographic storage was carried out using the photopolymer material prepared in Example 4, and reflection polarization holographic recording was performed on a three-dimensional object. The three-dimensional object is as shown in the appendix Figure 5 (a) and (b) are a copper coin with a diameter of 4 cm and a gypsum statue with dimensions of 5.5 cm in length, 1.8 cm in width, and 6 cm in height respectively. The optical path diagram is as shown in the appendix Figure 4 As shown, a single longitudinal mode semiconductor laser with a wavelength of 532 nm is used to generate a laser light source, which reaches the plane mirror M1 through an attenuator, and then reaches the half-wave plate 1 through the electronic shutter 1. At this time, the polarization beam splitter (PBS) divides the light source into two transmitted lights and reflected lights that are perpendicular to each other and have the same power. The transmitted light is reflected by the plane mirror M2, expanded by a beam expander, and used as the reference light to irradiate the obtained product photopolymer. The reflected light is expanded by a beam expander through the plane mirror M3 and irradiated onto the three-dimensional object through the plane mirror M4. The scattered light carrying the three-dimensional information of the object reaches the photopolymer and interferes with the reference light, thereby recording the object information on the photopolymer. After the exposure is completed, the electronic shutter 2 is closed, and the recorded three-dimensional object can be observed inside the photopolymer. The TI / PMMA material doped with SWNTs@ZSM-5 successfully realized the polarization holographic recording and reconstruction of the three-dimensional object, and restored the shape and details of the real object well.

[0073] The present invention first proves that the introduction of a three-dimensional carbon nanotube array (SWNTs@ZSM-5) can significantly enhance the polarization holographic performance of TI / PMMA photopolymers, achieving the highest polarization diffraction efficiency reported in photopolymers to date. When the doping concentration is 0.002 wt%, the polarization diffraction efficiency of this photopolymer reaches 22.74%, and through the recording and reconstruction of real objects, the polarization holographic recording ability of this photopolymer is verified.

[0074] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A photopolymer for improving polarization holographic performance, comprising raw materials in the following weight ratios: 100 g of methyl methacrylate, 4 g of photosensitizer Irgacure 784, 1.2 g of azobisisobutyronitrile, and 1 g of three-dimensional carbon nanotube array dispersion.

2. A method for preparing the photopolymer for improving polarization holographic performance according to claim 1, comprising the following steps: S1. Make a mold with a thickness of 1.5 mm using a silica gel gasket, and place the mold and syringe in an incubator at 60 °C. S2. Weigh 0.5 - 3.5 g of three-dimensional carbon nanotube arrays and add them to 10 g of methyl methacrylate solution, and perform constant-temperature oscillation treatment to uniformly disperse the three-dimensional carbon nanotube arrays in methyl methacrylate to obtain a three-dimensional carbon nanotube array dispersion for standby. S3. Weigh methyl methacrylate and place it in a dried brown bottle, and add the three-dimensional carbon nanotube array dispersion thereto, and perform constant-temperature oscillation treatment on the mixed solution to obtain a first mixed solution. S4. Add photosensitizer Irgacure 78 and azobisisobutyronitrile to the brown bottle in S3, and then perform constant-temperature oscillation treatment on the mixed solution to obtain a second mixed solution. S5. Place a magnetic rotor in the brown bottle of the second mixed solution, and then put it into a water bath magnetic stirrer and stir at a constant temperature until the solution in the brown bottle becomes viscous, and stop stirring to obtain a third mixed solution. S6. Take out the brown bottle of the third mixed solution, place it in a 60 °C water bath and ultrasonically oscillate for 2 min to obtain a fourth mixed solution. S7. Take out the syringe and mold in S1, draw the fourth mixed solution in S6 with the syringe, inject it into the mold, and then perform constant-temperature heat preservation treatment. After the heat preservation ends, obtain a solid photopolymer. S8. Place the solid photopolymer in a refrigerator at 2 °C, take it out after 2 h, and demold to obtain a photopolymer for improving polarization holographic performance.

3. According to the preparation method described in claim 2, wherein: The temperature of the constant-temperature oscillation treatment in step S2 is 60 °C, and the treatment time is 2 h.

4. According to the preparation method described in claim 2, wherein: The temperature of the constant-temperature oscillation treatment in step S3 is 60 °C, and the treatment time is 20 min.

5. According to the preparation method described in claim 2, wherein: The temperature of the constant-temperature oscillation treatment in step S4 is 60 °C, and the treatment time is 20 min.

6. According to the preparation method described in claim 2, wherein: The conditions of the constant-temperature stirring in step S5 are: the stirring temperature is 60 °C, the stirring speed is 3000 rpm, and the stirring time is 60 min.

7. According to the preparation method described in claim 2, wherein: The conditions of the constant-temperature heat preservation treatment in step S7 are: constant-temperature heat preservation at 60 °C for 24 h.

8. A photopolymer for improving polarization holographic performance prepared by the preparation method according to any one of claims 2 - 7.

9. An application of the photopolymer for improving polarization holographic performance according to claim 1 or 8 in the preparation of holographic optical elements.

10. According to the application described in claim 9, wherein: The holographic optical element is a holographic storage material.

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