Solid optical material and preparation method thereof

Abstract

The invention relates to a solid optical material and a preparation method thereof, in particular to a photochromic solid optical material which can be used for space static three-dimensional imaging. The material comprises salicylaldehyde aniline, methyl methacrylate, 4-vinyl benzocyclobutene, (Z)-3-hexenyl-3-catechol borate and an initiator, and the optical transparency and the imaging stability of the material are improved by optimizing a curing process. The preparation method of the solid optical material comprises the processes of material mixing, thermal polymerization, step-by-step curing and post-treatment. Experimental results show that the material has high light transmittance and photochromic characteristics, and can be used for high-precision three-dimensional imaging.

Description

Technical Field

[0001] The invention relates to the field of optical functional materials, in particular to a solid optical material and a preparation method thereof. Background Art

[0002] With the development of science and technology, the demand for information visualization is growing, especially in the fields of medical imaging, aerospace, virtual reality (VR), augmented reality (AR), etc. Three-dimensional (3D) display technology has become an important research direction. Currently, common three-dimensional display technologies mainly include stereoscopic display, holographic display and volumetric three-dimensional display.

[0003] Among them, volumetric 3D display has important development prospects in future display technology due to its unlimited viewing angle and strong imaging realism. However, existing technologies still have many limitations in volumetric 3D display materials, mainly including: Existing photochromic materials are difficult to meet the needs of 3D imaging: most traditional photochromic materials are in liquid solution or powder state, such as organic dyes (Spiropyran, Diarylethene), metal complexes ( ) etc. These materials are easy to diffuse in the liquid or gas phase, and it is difficult to stably maintain the three-dimensional imaging effect; while solid-state photochromic materials are usually opaque or have low light transmittance and are not suitable for high-resolution optical imaging.

[0004] Limited selection of transparent optical materials: Currently, transparent materials used in 3D optical storage and volumetric 3D imaging are mostly inorganic glass (such as quartz glass, silicate glass) or polymer-based materials (such as PMMA, polycarbonate). However, inorganic glass materials are expensive and difficult to process, while existing polymer materials are prone to degradation or aging at high temperatures, affecting the stability of optical properties. Therefore, it is necessary to develop a new type of optical material that has both high transmittance and can stably carry photochromic components.

[0005] Photochromic materials are a type of smart material that can change color under specific lighting conditions. They are mainly used in the fields of optical anti-counterfeiting, sensing, and display. In the field of three-dimensional imaging, photochromic materials can control lighting conditions to form a stable optical contrast at a specific position in space, thereby constructing a three-dimensional image.

[0006] However, the application of traditional photochromic materials in volumetric three-dimensional display is subject to the following limitations: slow color change response speed, affecting dynamic display effects; low transparency, affecting light penetration and imaging clarity. Summary of the invention

[0007] In order to overcome at least one of the technical problems in the above background technology, the present invention provides a method for preparing a solid optical material. The solid optical material prepared by the method can play an important role in the fields of optical three-dimensional display, information encryption, holographic anti-counterfeiting, etc., and has broad application prospects.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows: A solid optical material, comprising, by weight: Salicylaldehyde aniline: 0.01-0.1 parts; Methyl methacrylate: 100 parts; 4-vinylbenzocyclobutene: 0.3-0.8 parts; (Z)-3-Hexenyl-3-boric acid catechol ester (CAS: 37490-28-1): 0.08-0.2 parts; Initiator: 0.1~3 parts.

[0009] According to some embodiments of the present invention, the initiator is selected from at least one of azobisisobutyronitrile (AIBN), azobisisoheptanenitrile (AIHN), benzoyl peroxide (BPO), lauroyl peroxide, and cumene hydroperoxide.

[0010] A method for preparing a solid optical material comprises the following steps: 1) Material mixing: Disperse 0.01-0.1 parts of salicylaldehyde aniline uniformly in 100 parts of methyl methacrylate by mass; add 0.3-0.8 parts of 4-vinylbenzocyclobutene and 0.08-0.2 parts of (Z)-3-hexenyl-3-boric acid catechol ester in sequence; add 0.1-3 parts of initiator and stir for 10-30 minutes until completely dissolved; 2) Thermal polymerization reaction: Raise the temperature to the reaction temperature and maintain it for 0.5 to 3 hours to allow the system to undergo free radical polymerization and thicken the reaction solution; 3) Curing treatment: Use programmed temperature curing, water bath heating, gradually increase the temperature, reduce internal stress, and enhance the mechanical strength and optical uniformity of the material; 4) Post-processing: Use cutting, grinding and splicing processes to improve the surface smoothness of the material and enhance optical transparency.

[0011] According to some embodiments of the present invention, the stirring speed in the material mixing step is 300-500 rpm.

[0012] According to some embodiments of the present invention, the reaction temperature in the thermal polymerization step is 50-100°C.

[0013] According to some embodiments of the present invention, the programmed temperature curing step in the curing step is: Initial curing: constant temperature curing at 45-60°C for 18-24 hours; Secondary curing: raise the temperature to 60-80°C and maintain for 6-12 hours; Final curing: Raise the temperature to 80-100°C and maintain for 1-2 hours.

[0014] The beneficial effects of this method on solid optical materials: Improve light transmittance: The cross-linked network formed inhibits the occurrence of polymer phase separation, making the internal structure of the material more uniform and reducing the occurrence of light scattering. At the same time, the dynamic bond rearrangement of (Z)-3-hexenyl-3-boric acid catechol ester also helps to reduce internal defects and stress concentration, further reducing light scattering, thereby improving the light transmittance of the material in the visible light region, making the material have better optical transparency and achieving high-quality three-dimensional imaging.

[0015] Regulating the refractive index: The benzene ring structure in 4-vinylbenzocyclobutene and the borate group in (Z)-3-hexenyl-3-boric acid catechol ester have a high refractive index. Their introduction can adjust the overall refractive index of the material to meet the refractive index requirements of different optical applications and achieve precise regulation of the refractive index.

[0016] Reduce birefringence: The dynamic bond rearrangement of (Z)-3-hexenyl-3-boric acid catechol ester makes the orientation of the molecular chain more random and uniform, reducing the orientation difference of the molecular chain, thereby reducing the birefringence of the material, improving the consistency of the material's optical properties, and improving the three-dimensional imaging resolution.

[0017] Improve the optical response speed: Salicylaldehyde aniline is used as the photochromic molecule, and its molecular structure undergoes a proton transfer reaction under ultraviolet light. The content of salicylaldehyde aniline is controlled to ensure a fast and uniform color change response. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example 1

[0020] 1) Material mixing Take 0.05 g of salicylaldehyde aniline, add it into 100 g of methyl methacrylate, and stir evenly; 0.5 g of 4-vinylbenzocyclobutene and 0.15 g of (Z)-3-hexenyl-3-boronic acid catechol ester were added in sequence; Add 1.5 g of azobisisobutyronitrile (AIBN) as an initiator; Stir for 25 minutes at 400 rpm until the solution is completely mixed.

[0021] 2) Thermal polymerization The temperature was gradually raised to 80°C and maintained for 2.5 hours. Free radical polymerization occurred in the system and the reaction solution thickened to a uniform viscous state.

[0022] 3) Curing treatment (programmed temperature curing, water bath heating) Initial curing: constant temperature curing at 45°C for 20 hours; Secondary curing: heat to 70°C and maintain for 10 hours; Final curing: Raise the temperature to 90°C and maintain for 1.5 hours until the material is cured.

[0023] 4) Post-processing Using precision cutting equipment, the solidified material was cut into 3×3×3 cm transparent optical sheets; Use a polishing machine to grind the surface to reduce light scattering and improve light transmittance.

[0024] Example 2

[0025] 1) Material mixing Take 0.02 g of salicylaldehyde aniline, add it into 100 g of methyl methacrylate, and stir evenly; 0.3 g of 4-vinylbenzocyclobutene and 0.08 g of (Z)-3-hexenyl-3-boronic acid catechol ester were added in sequence; Add 2.5 g of benzoyl peroxide (BPO) as an initiator; Stir for 30 min at 500 rpm to ensure a homogeneous solution.

[0026] 2) Thermal polymerization The temperature was gradually raised to 70°C and maintained for 3 hours to allow the reaction system to gradually thicken and form a pre-cured state.

[0027] 3) Curing treatment (programmed temperature curing, water bath heating) Initial curing: constant temperature curing at 50°C for 18 hours; Secondary curing: heat to 60°C and maintain for 8 hours; Final curing: Raise the temperature to 80°C and maintain for 2 hours until the material is cured.

[0028] 4) Post-processing Cut into 5×5×1 cm transparent optical sheets using a laser cutter; Nano-level polishing technology is used for fine surface treatment.

[0029] Example 3

[0030] 1) Material mixing Take 0.08 g of salicylaldehyde aniline, add it into 100 g of methyl methacrylate, and stir evenly; 0.7 g of 4-vinylbenzocyclobutene and 0.2 g of (Z)-3-hexenyl-3-boronic acid catechol ester were added in sequence; 0.8 g of lauroyl peroxide was added as an initiator; Stir for 20 minutes at 350 rpm to ensure a smooth mix.

[0031] 2) Thermal polymerization The temperature was gradually raised to 90°C and maintained for 1 hour to allow the polymer to gradually form a network structure and increase viscosity.

[0032] 3) Curing treatment (programmed temperature curing, water bath heating) Initial curing: constant temperature curing at 55°C for 22 hours; Secondary curing: heat to 75°C and maintain for 6 hours; Final curing: Raise the temperature to 100°C and maintain for 1 hour until the material is cured.

[0033] 4) Post-processing Precision laser cutting was used to produce a 2×2×2 cm optical device; High-precision mechanical polishing is used to improve optical uniformity.

[0034] Example 4

[0035] 1) Material mixing Take 0.03 g of salicylaldehyde aniline, add it into 100 g of methyl methacrylate, and stir evenly; 0.4 g of 4-vinylbenzocyclobutene and 0.12 g of (Z)-3-hexenyl-3-boronic acid catechol ester were added in sequence; Add 1.2 g of cumene hydroperoxide as an initiator; Stir for 15 minutes at 300 rpm to ensure a homogeneous solution.

[0036] 2) Thermal polymerization The temperature was gradually raised to 60°C and maintained for 2 hours to allow the solution to become viscous.

[0037] 3) Curing treatment (programmed temperature curing, water bath heating) Initial curing: constant temperature curing at 48°C for 24 hours; Secondary curing: heat to 65°C and maintain for 12 hours; Final curing: Raise the temperature to 85°C and maintain for 1.5 hours until the material is cured.

[0038] 4) Post-processing The CNC machine tool is used for precision cutting to produce 4×4×0.5 cm transparent optical sheets; Use nano polishing liquid for polishing to improve smoothness.

[0039] Comparative Example 1 The only difference between this example and Example 1 is that 4-vinylbenzocyclobutene is not added.

[0040] Comparative Example 2 The only difference between this example and Example 1 is that no (Z)-3-hexenyl-3-boric acid catechol ester is added.

[0041] The test method involved in the present invention is as follows: 1) Light transmittance test Test method: Use UV-Vis Spectrophotometer to measure the light transmittance of the material in the 400-700nm band. The wavelength of the test light source is set to 550nm (the strongest transmission area of ​​visible light).

[0042] 2) Photochromic response test Test method: Use a 365nm ultraviolet LED light source (power 200mW) to irradiate the sample for 10s and observe the color change of the material; use a 532nm green laser (power 50mW) to irradiate the color change area and observe the formation of a three-dimensional fluorescent image; use an optical microscope (100× magnification) + a high-speed camera to record the color change process. Record the time required for the material to completely change color after ultraviolet light irradiation, as well as the response time of green light to excite red fluorescence.

[0043] Table 1 Test results Light transmittance (%) Color change time (s) Fluorescence response time (s) Example 1 96.1 1.5 0.8 Example 2 95.7 1.8 1.0 Example 3 97.0 1.2 0.7 Example 4 96.5 1.4 0.9 Comparative Example 1 95.0 2.1 1.3 Comparative Example 2 95.3 2.0 1.1 The solid optical material of the present invention is significantly superior to the comparative example in terms of light transmittance, photochromic speed and fluorescence excitation. The material can be widely used in high-tech fields such as three-dimensional optical dynamic information display, anti-counterfeiting identification, and reversible optical marking.

[0044] The above is only a preferred specific implementation manner of the present invention, and the protection scope of the present invention is not limited thereto. Any simple change or equivalent replacement of the technical solution that can be obviously obtained by any technician familiar with the technical field within the technical scope disclosed in the present invention falls within the protection scope of the present invention.

Claims

1. A solid optical material, characterized in that: In parts by mass, its composition includes: Salicylaldehyde aniline: 0.01-0.1 parts; Methyl methacrylate: 100 parts; 4-vinylbenzocyclobutene: 0.3-0.8 parts; (Z)-3-Hexenyl-3-boric acid catechol ester: 0.08-0.2 parts; Initiator: 0.1~3 parts.

2. A solid optical material according to claim 1, characterized in that: The initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptylnitrile, benzoyl peroxide, lauroyl peroxide, and cumene hydroperoxide.

3. A method for preparing a solid optical material, characterized in that: The steps include: 1) Material mixing: Disperse 0.01-0.1 parts of salicylaldehyde aniline uniformly in 100 parts of methyl methacrylate by mass; add 0.3-0.8 parts of 4-vinylbenzocyclobutene and 0.08-0.2 parts of (Z)-3-hexenyl-3-boric acid catechol ester in sequence; add 0.1-3 parts of initiator and stir for 10-30 minutes until completely dissolved; 2) Thermal polymerization reaction: Raise the temperature to the reaction temperature and maintain it for 0.5 to 3 hours to allow the system to undergo free radical polymerization and thicken the reaction solution; 3) Curing treatment: Use programmed temperature curing, water bath heating, gradually increase the temperature, reduce internal stress, and enhance the mechanical strength and optical uniformity of the material; 4) Post-processing: Use cutting, grinding and splicing processes to improve the surface smoothness of the material and enhance optical transparency.

4. The method for preparing a solid optical material according to claim 3, characterized in that: The stirring speed in the material mixing step is 300-500 rpm.

5. The method for preparing a solid optical material according to claim 3, characterized in that: The reaction temperature in the thermal polymerization step is 50-100°C.

6. The method for preparing a solid optical material according to claim 3, characterized in that: The programmed temperature curing step in the curing treatment step is: Initial curing: constant temperature curing at 45-60°C for 18-24 hours; Secondary curing: raise the temperature to 60-80°C and maintain for 6-12 hours; Final curing: Raise the temperature to 80-100°C and maintain for 1-2 hours.